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6 MINISTRY OFHEALTHA

:

NPPiJI NT

R ,r'

S,T"'P4DARDSI. it!

995

DRINKING-WATER

STANDARDS

FOR

NEW ZEALAND

1995

092743

MINISTRY OF

HEALTHMANATU HAUORA

Information CentreMinisty of HealthWellington

PREFACE

lam pleased to extend the Ministry of Health's programme to improve the quality of drinking-water with the release of the Drinking-Water Standards for New Zealand 1995. TheseStandards will become effective from 1 January 1995 and will replace the 1984 Drinking-Water Standards for New Zealand.

The revised drinking water Standards are a significant achievement in New Zealand'sendeavours to maintain and improve water quality.

The Standards complement the modified grading criteria for public drinking water suppliesand form an integral part of the water grading process which determines how well a watersupply meets the minimum requirements. In the past, water supplies were graded largely onthe basis of the method of treatment used. The new system emphasises the reliability of thesafety of the drinking water supply, based on what emerges from the householders' tap. Thiswill give all consumers, commercial and domestic greater confidence in the quality of theirwater.

The Ministry of Health is also improving its records of water supplies around the country bydeveloping a national register of water supplies. This register will ensure more accurateinformation is available to planners and the public.

I congratulate the Working Party on the considerable effort that has gone into preparing theStandards. Special mention should also be made of those individuals and organisations whichcommented on the draft Standards. The result is a major improvement for the futuremanagement of public drinking water supplies.

Christopher LovelaceDirector-General of Health

\

CONTENTS

EXPERT COMMITTEE ON DRINKING-WATERQUALITY

IX

OVERVIEW OF THE DRINKING-WATER STANDARDS 11.1 Introduction 11.2 Scope of the Standards 21.3 Development of the Standards 21.4 Role of the Standards 31.5 Content of the Standards 31.6 Maximum Acceptable Values (MAVs) 41.7 Components of a drinking-water supply 5

1.7.1 Source water 61.7.2 The treatment plant 61.7.3 The distribution system 6

2 DETERMINATION OF COMPLIANCE

82.1 Introduction 82.2 Compliance and transgression 82.3 Selection ofdeterminands 9

2.3.1 Introduction 92.3.2 Priority classes for drinking-water determinands 9

2.3.2.1 Priority 1 92.3.2.2 Priority 2 102.3.2.3 Priority 3 112.3.2.4 Priority 4 12

3 MICROBIOLOGICAL COMPLIANCE

133.1 Introduction 133.2 Rationale for microbiological MAVs 13

3.2.1 Faecal coliforms 133.2.2 jGiardia and Cryptosporidium 14

3.3 Microbiological compliance criteria 143.3.1 General microbiological criteria 14

111

3.3.2 Faecal coliforms 153.3.2.1 Faecal coliform compliance criteria for drinking-

water leaving a treatment plant

153.3.2.2 Faecal coliform compliance criteria for drinking-

water in a distribution zone 153.3.3 Giardia 15

3.3.3.1 Giardia compliance criteria for drinking-waterleaving a treatment plant 15

3.3.4 Cryptosporidium 163.3.4.1 Cryptosporidium compliance criteria for

drinking-water leaving a treatment plant 16

3.4 Microbiological monitoring requirements 173.4.1 Microbiological sampling sites 173.4.2 Microbiological sampling frequencies 18

3.4.2.1 Faecal coliforms 183.4.2.1.1 Faecal coliforms in drinking-water

leaving a treatment plant 183.4.2.1.2 Faecal coliforms in a distribution zone193.4.2.1.3 Free available chlorine and faecal

coliforms in a distribution zone203.4.2.2 Giardia 21

3.4.2.2.1 Giardia in drinking-water leaving atreatment plant 21

3.4.2.3 Cryptosporidium 223.4.2.3.1 Cryptosporidium in drinking-water

leaving a treatment plant 223.4.3 Microbiological sampling requirements 23

3.4.3.1 Faecal coliforms 233.4.3.2 Free available chlorine 233.4.3.3 Turbidity 23

3.4.4 Microbiological analytical requirements 243.4.4.1 Bacteriological referee methods 243.4.4.2 Free available chlorine referee method

24

3.4.4.3 Turbidity referee method

25

3.5 Action to be taken when transgression of a microbiologicalMAV occurs 253.5.1 Faecal coliform transgressions 25

3.5.1.1 Faecal coliforms in drinking-water leaving atreatment plant 25

3.5.1.2 Faecal coliforms in drinking-water in adistribution zone 27

iv

3.5.1.2.1 Faecal coliforms present 273.5.1.2.2 Free available chlorine too low 28

3.5.2 Giardia and Cryptosporidium transgressions 283.5.2.1 Turbidity in drinking-water leaving a treatment plant 283.5.2.2 Disinfection contact time 30

4 CHEMICAL COMPLIANCE

314.1 Introduction 314.2 Rationale for chemical MAVs 314.3 Compliance criteria for chemicals 314.4 Chemical monitoring requirements 32

4.4.1 Chemical sampling sites 334.4.2 Chemical sampling frequencies 364.4.3 Chemical sampling requirements 374.4.4 Chemical analytical requirements 37

4.5 Transgression of a chemical MAV 38

5 RADIOLOGICAL COMPLIANCE

395.1 Introduction 395.2 Rationale for radiological MAVs 395.3 Radiological compliance criteria 405.4 Radiological monitoring requirements 405.5 Transgression of a radiological MAV 40

6 RECORDS

41

7 DEFINITIONS

42

8 UNITS

49

9 INDEX OF SYNONYMS

52

10 TABLES OF SYNONYMS

60

11 SAMPLING AND ANALYTICAL REQUIREMENTS FORCHEMICAL DETERMINANDS OF HEALTHSIGNIFICANCE 66

v

LIST OF TABLES AND FIGURES

Figure 1Schematic diagram of a drinking-water supply system. 5

Table 3.1Minimum recommended sampling frequency for faecal coliforms indrinking-water leaving a treatment plant. 18

Table 3.2Minimum recommended sampling frequency for faecal coliforms indrinking-water in a distribution zone. 20

Table 3.3Approximate minimum sampling frequency for faecal coliforms and freeavailable chlorine in a distribution zone. 21

Table 3.4Minimum sampling frequency for turbidity in drinking-water leaving atreatment plant, for Giardia Compliance Criterion lb. 22

Figure 3.1 Response to faecal coliform contamination of drinking-water leaving atreatment plant. 26

Figure 3.2 Response to faecal coliform contamination of a water supply distributionzone. 27

Figure 3.3 Response to turbidity transgression for drinking-water leaving a treatmentplant. 29

Figure 3.4 Response to disinfectant CA transgression for drinking-water leaving atreatment plant. 30

Figure 4.1 Establishing compliance of Priority 2 determinands with the Standards. 35

Table 4.1Monitoring requirements for Priority 2a and 2b determinands.1 37

Table 10.1 Synonyms for organic determinands of health significance. 60

Table 10.2 Synonyms for pesticides. 63

Table 11.1 Sampling requirements, referee method and some alternative analyticalmethods for inorganic determinands of health significance. 67

Table 11.2 Sampling requirements, referee method and some alternative analyticalmethods for organic determinands of health significance. 68

vii

Table 11.3Sampling requirements, referee method and some alternative analyticalmethods for pesticides. 71

Table 12.1 C.t values for 99.9% inactivation of Giardia lamblia by free chlorine at0.5°C or lower and turbidity below 1 NTU. 76

Table 12.2 C.t values for 99.9% inactivation of Giardia lamblia by free chlorineat 5.0°C and turbidity below 1 NTU. 76

Table 123 C.t values for 99.9% inactivation of Giardia lamblia by free chlorine at10.0°C and turbidity below 1 NTU. 77

Table 12.4 CA values for 99.9% inactivation of Giardia lamblia by free chlorine at15.0°C and turbidity below 1 NTU. 77

Table 12.5 CA values for 99.9% inactivation of Giardia lamblia by free chlorine at20.0°C and turbidity below 1 NTU. 78

Table 12.6 C.t values for 99.9% inactivation of Giardia lamblia by free chlorine at25.0°C and higher, turbidity below 1 NTU. 78

Table 12.7 CA values for 99.9% inactivation of Giardia lamblia cysts by chlorinedioxide and ozone with turbidity below 1 NTU. 79

Table 12.8 Disinfectant concentration and contact time for 90% inactivation ofCryptosporidium by chlorine dioxide and ozone with turbidity below1NTU. 79

Table 13.1 MAVs for micro-organisms of health significance. 80

Table 13.2 MAVs for inorganic determinands of health significance. 81

Table 13.3 MAVs for organic determinands of health significance. 82

Table 13.4 MAVs for pesticides. 84

Table 13.5 MAVs for radiological determinands. 86

Table 13.6 Guideline Values for aesthetic determinands. 87

viii

NATIONAL DRINKING-WATERSTANDARDS REVIEW EXPERTWORKING GROUP

David AdamsonWater Supply EngineeringRotorua District CouncilPrivate Bag 3029Rotorua

Tim BrownMicrobiologyDepartment of Microbiology & GeneticsMassey UniversityPrivate Bag 11222Palmerston North

Richard ChandlerWater Supply ManagementWatercare Services LtdPrivate Bag 92521Wellesley StreetAuckland

Joanne Davies, EditorWater ChemistryInstitute of Environmental Science and

Research LtdP0 Box 29-181Christchurch

Paul LynchHealth ProtectionRegional Health Development UnitHealth WaikatoP0 Box 485Hamilton

Sally HassellMicrobiologyInstitute of Environmental Science and


Rob BlakemoreWater Supply Treatment EngineeringBulk Water Supply DepartmentWellington Regional CouncilP0 Box 11-646Wellington

Kevin CampbellHealth ProtectionSouthern HealthP0 Box 828Invercargill

Stu ClarkWater Engineering TreatmentSmall Community SuppliersWorks Consultancy Services LimitedWater Treatment CentreP0 Box 47-004Trentham

Johnathan Fletcher(Former Member)Public Health EngineeringWater Supply DepartmentChristchurch City CouncilChristchurch

David Ogilvie, EditorWater Quality ScienceConsultantP0 Box 60-217Waitakere City

Paul PrendergastPublic Health EngineeringPublic Health Regulatory ServicesMinistry of HealthP0 Box 5013Wellington

lx

Max RobertsonWater ChemistryQuality ManagementGrayson LaboratoriesW Grayson & Associates LtdP0 Box 12-545PenroseAuckland

Alistair SheatChemistryInstitute of Environmental Science and


Michael Taylor, Chairman, EditorChemistryPublic Health Regulatory ServicesMinistry of HealthP0 Box 5013Wellington

Desmond TillMicrobiologyCommunicable Disease CentreInstitute of Environmental Science and

Research LtdP0 Box 50-348PoriruaWellington

The radioactivity section was provided by:Murray MatthewsPhysicsNational Radiation LaboratoryP0 Box 25-099Christchurch

Chris Shaw, Former ChairmanChemistryPublic Health Regulatory ServicesMinistry of HealthP0 Box 5013Wellington

Vivienne SmithGroundwater QualityCanterbury Regional CouncilP0 Box 345Christchurch

Wayne TempleToxicologyNew Zealand National Poisons/Hazardous Chemicals Information CentreP0 Box 913Dunedin

Jim WatersToxicologyPublic Health Regulatory ServicesMinistry of HealthP0 Box 5013Wellington

x

1 OVERVIEW OF THE DRINKING-WATER STANDARDS

1.1 INTRODUCTIONSafe drinking-water which is available to everyone is a fundamental requirement for publichealth.

The Drinking-Water Standards for New Zealand 1995 will be adopted by the Ministry ofHealth from 1 January 1995. They detail how to assess the quality and safety of drinking-water. The Standards define drinking-water as water which is intended primarily for humanconsumption. It may be consumed either directly from the tap or indirectly in food andbeverages. The Standards provide criteria applicable to all drinking-water (except bottledwater which must comply with the Food Act 1981) and will be used as the basis for gradingthe quality of community drinking-water supplies.

Water will always contain dissolved and particulate substances. Few of the dissolvedsubstances pose any threat to public health, indeed many are beneficial in small amountsand may contribute to the palatability of the water. Public health risks may arise however, ifcontaminants such as toxic substances or harmful micro-organisms are present in excessiveamounts in the water.

Drinking-Water Standards for New Zealand 1995 list the maximum concentrations ofchemical, radiological and microbiological contaminants acceptable for public health indrinking-water. For community drinking-water supplies, the Standards also specify thesampling protocols which must be met to demonstrate that the water complies with theStandards. Community drinking-water supplies are water supplies which serve 25 people ormore for at least 60 days per year.

Because of the wide variety of circumstances relating to individual household drinking-watersupplies no general recommendations are given for such supplies. If there is any concernabout the quality of a household's drinking-water, advice on appropriate samplingprogrammes can be obtained either from the environmental health officers of the localterritorial authority or the health protection officers at the crown health enterprise.

Recent advances in knowledge have led to an increase in the range of substances now knownto present a toxicological risk since the previous Standards were published in 1984. In somecases, there is a change between the 1984 Guideline Value and the 1995 Maximum AcceptableValue (MAV). In addition, the Standards have been drafted to define compliance or non-compliance more clearly.

Toxic chemical contaminants in drinking-water rarely lead to acute health problems exceptthrough massive accidental contamination of a supply. Before it presents a health risk thewater usually becomes undrinkable due to unacceptable taste, odour or appearance.

The problems associated with chemical contaminants of drinking-water arise primarily fromtheir ability to cause adverse health effects after prolonged periods of exposure. Of particularconcern are contaminants which have cumulative toxic properties, such as some heavy metalsand substances which are carcinogenic.

Because chemical contaminants of drinking-water do not usually give rise to acute effectsthey are placed in a lower priority category than microbial contaminants, the effects of which

are potentially acute and widespread. The control of risks arising from microbiologicalcontamination is, therefore given priority over the control of risks from chemicalcontaminants.

The Drinking- Water Standards for New Zealand 1995 are intended to:

•Set out the requirements for compliance with the Standards;

•Facilitate consistency of application throughout New Zealand;

•Protect public health while minimising unnecessary monitoring;

•Be appropriate for both large and small drinking-water supplies.

1.2 SCOPE OF THE STANDARDSThe Standards are applicable to water intended for drinking, irrespective of its source,treatment, distribution system, or where it is used. The exception is bottled water, which issubject to different standards set under the Food Regulations. The Standards address waterproperties of public health significance. Aesthetic considerations are discussed in thecompanion document, Guidelines for Drinking-Water Quality Managemen tin New Zealand1995, together with additional information about determinands listed in the Standards, themanagement of drinking-water quality and the derivation of the concepts used in theStandards.

Guideline values for aesthetic determinands are also given in Table 13.6. These guidelinevalues are included as a guide to aesthetically acceptable water. It is not necessary to meet thevalues for aesthetic determinands to achieve compliance with the Standards.

1.3 DEVELOPMENT OF THE STANDARDSThe Standards were developed by the Ministry of Health with the assistance of an ExpertCommittee. Extensive use was made of the World Health Organization's Guidelines forDrinking-Water Quality 1993. Reference was also made to the Drinking-Water Standardsfor New Zealand 1984 and the DraftAustralian Drinking Water Guidelines 1993. The finalDrinking-Water Standards for New Zealand 1995 were developed from a draft versionfollowing public consultation.

The Standards are based on the following principles:

1. The Standards define contaminant concentrations at which, based on current knowledge,the water is considered to constitute no significant risk to health. It is usually not possibleto define a concentration of contaminant (other than zero) at which there is zero risk asthere is always some degree of uncertainty over the magnitude of the risk.

2. The Standards give top priority to health risks arising from microbiological contaminants.Control of microbial contamination must be of paramount importance and must notbe compromised in an attempt to correct chemical problems, such as disinfection by-product formation.

3. The Standards set priorities to ensure that, while public health is protected, scarceresources are not diverted to monitoring substances of relatively minor importance.

2

4. The Standards are set to protect public health and cover health significant determinandsonly. However, because the public generally assesses the quality of its water supply onaesthetic perceptions, guideline values for aesthetic determinands are also included. Referto the accompanying Guidelines for more details.

The Ministry of Health initially intended to establish sampling protocols which would give95 percent confidence that the supply complied with the Standards for at least 95 percent ofthe time. However, it found this target could not be achieved without setting unrealisticallyhigh monitoring frequencies. A minimum of 58 samples, none of which transgresses theMAy, is required before the Ministry can be 95 percent confident that the supply complieswith the Standards for 95 percent of the time. Not more than one transgression in 93 samplesis acceptable if the Ministry is to remain 95 percent confident that the water complies withthe Standards for 95 percent of the time.

If samples are collected weekly, provided no sample transgresses the Standards in 13.5 monthsof sampling (58 weeks), there will be 95 percent confidence that the supply complies withthe Standards for 95 percent of the time.

However, for those determinands monitored monthly:

The supply will not comply with the Standards if one or more samples exceed theMAV in twelve samples. The Ministry of Health can be 54 percent confident that thetrue exceedence rate is greater than five percent.

• The Ministry of Health can be 95 percent confident that the supply complies and thatthe true exceedence rate is no more than 22 percent if no sample exceeds the MAV intwelve samples. That is, the Standards are being complied with 78 percent of the time.

As data accumulate over the years it will be possible to improve on the confidence with whichthe compliance can be demonstrated.

1.4 ROLE OF THE STANDARDSThe Drinking- Watei-StandardsforNewZealandl995contribute to the safety and quality ofdrinking-water by:

•Defining safety standards for drinking-water.

•Detailing how compliance with these Standards can be demonstrated.

•Facilitating the development of a consistent approach to the evaluation of the qualityof the country's drinking-water supplies.

•Providing a basis for the management of drinking-water quality.

1.5 CONTENT OF THE STANDARDSThe Drinking-Water Standards for New Zealand 1995 set Standards for drinking-waterconstituents or properties (determinands) and contain the information necessary todemonstrate whether a water supply complies with these Standards. Three types ofcompliance are included in these Standards: microbiological, chemical and radiological.

The Standards define the Maximum Acceptable Value (MAV) for each determinand. This isusually the concentration at which the risk resulting from consumption of the contaminant

over a lifetime is considered to be insignificant in the light of present knowledge. TheMaximum Acceptable Values (MAVs) are discussed in Section 1.6.

The determinands have been classified into four priority classes. Priority 1 applies to alldrinking-water. Priority 2 determinands are determinands which are present at over 50 percent of the MAy. Priority 1 and 2 determinands must be shown to comply with therequirements of the Standards. Whether a determinand falls into Priority 2, 3 and 4 dependsupon the characteristics of the water supply. These priorities are supply specific. The priorityclasses are discussed in Section 2.3.2.

The monitoring and analytical requirements needed to demonstrate compliance for thosedeterminands in Priorities 1 and 2 are given in Chapters 3,4 and 5 for microbiological, chemicaland radiological determinands respectively. MAVs for each of the individual health significantdeterminands are given in Chapter 13.

The companion volume Guidelines forDrinking- Water Quality Managem ent for NewZealand1995 provides background and supporting information for the Standards and will be revisedregularly. It contains:

• Data sheets with background information about each determinand including sources,environmental forms and fates, typical concentrations either in New Zealand oroverseas drinking-water supplies, processes for removing the determinand fromdrinking-water, analytical methods, health considerations, derivation of the MAV andthe guideline values for determinands of aesthetic interest.

•Chapters for microbiological, chemical and radiological determinands providingbackground information about each group of determinands.

•Background information about chlorine and alternative disinfection systems and theirimpact on drinking-water quality.

Guidelines and good management principles for community drinking-water supplies.

1.6 MAXIMUM ACCEPTABLE VALUES (MAV)The Maximum Acceptable Value (MAV) of a determinand in a drinking-water represents theconcentration of a determinand which, on the basis of present knowledge, is not consideredto cause any significant risk to the health of the consumer over a lifetime of consumption ofthe water.

Nearly all of the MAVs for the determinands covered in these Standards are based on theWorld Health Organization (WHO) publication Guidelines forDrinking- Water Quality1993.The method of derivation depends upon the particular way in which the determinand presentsa health risk. For some chemical determinands, adaptation of the method of derivation tosuit New Zealand conditions has resulted in a minor difference between the guideline valuerecommended by WHO and the MAVs in these Standards.

In addition, some chemical determinands not covered by the WHO publication GuidelinesforDrinking- Water Quality 1993 have been added to these Standards because of their publichealth significance in New Zealand circumstances. MAVs of these determinands have beencalculated using methods appropriate to the situation. In all cases the approach wasconservative and considerable safety factors have been used.

4

A general discussion on the methodology of the derivation of the MAVs is given in theGuidelines for Drinking-Water Quality Management for New Zealand 1995 together withspecific information about the derivation of the MAV for each individual determinand.

It should be noted that:

1. The MAVs set in the Standards define water suitable for human consumption andhygiene. Water of higher quality may be required for special purposes, such as renaldialysis or certain industrial processes. The Standards do not address these issues.

2. Short-term excursions above the MAV do not necessarily mean the water is unsuitablefor consumption. Most MAVs have been derived on the basis of a lifetime exposure.The amount and the duration any MAV can be exceeded without affecting public health

- depends on the characteristics of the determinand.

3. The MAV values are set to be acceptable for lifelong consumption. The quality ofdrinking-water should not, however, be degraded to the MAV level. Ongoing effort shouldbe made to maintain drinking-water quality at the highest possible level.

4. For radioactive substances, screening values for gross a and gross b activity are given,based on a reference level of dose.

1.7 COMPONENTS OF A DRINKING-WATERSUPPLY

A community water supply comprises one or more of each of the following (see Figure 1):

the source or raw water

the treatment plant

the distribution system.

Figure 1 Schematic diagram of a drinking-water supply system.

River \/GroundLake-\water

Source )Source} (—Source

Treatment TreatmentPlant Plant

A B

[r'DunoDistribution.)

DistributionZone Zone Zone

X Y Z

1.7.1 SOURCE WATER

JA community water supply may abstract raw water from rainwater, surface water orgroundwater sources.

Surface water is frequently contaminated by micro-organisms. Shallow groundwater and somesprings are microbiologically equivalent to surface water, along with rivers, streams, lakesand reservoirs. Secure groundwater, as defined in footnotes 1 and 2 to Table 3.1, is usuallyfree from microbiological contamination.

A water supply may have more than one source of raw water. Secondary sources may bepermanent or-temporary.

1.7.2 THE TREATMENT PLANTA treatment plant is a facility which treats raw water to make it safe and palatable for drinking.To harmonise the Standards with the conventions used in the public health grading ofcommunity drinking-water supplies, the treatment plant is considered to be that part of thesystem where raw water becomes the drinking-water. This can range from a full scale watertreatment plant comprising chemical coagulation, sedimentation, sand filtration, pHadjustment, disinfection and fluoridation, to simply being the point in a pipeline where thewater main changes from a raw water main to a drinking-water supply main. In a simplewater supply, the water may be merely abstracted from a river, passed through a coarse screenand travel to town, that is, the water supply acts like a diverted stream. If raw water ischlorinated, however, the water will not be considered to become drinking-water until it hasbeen exposed to chlorine for the design contact time. A treatment plant may receive rawwater from more than one source.

1.7.3 THE DISTRIBUTION SYSTEMOnce the water leaves the water treatment plant, it enters one or more distribution zone(s)which serve the community. The Standards and the 1993 public health grading of drinking-water supplies define a distribution zone as:

"...part of the drinking-water supply network within which all consumers receive drinking-water of identical quality, from the same or similar sources, with the same treatment andusually at the same pressure. It is part of the supply network which is clearly separated fromother parts of the network, generally by location, but in some cases by the layout of the pipenetwork. For example, in a large city, the central city area may form one zone, with outlyingsuburbs forming separate zones, or in a small town, the system may be divided into two distinctareas. The main purpose of assigning zones is to separately grade parts of the system withdistinctly different characteristics."

A distribution zone may receive water from more than one treatment plant. The distributionsystem may comprise more than one distribution zone. (See Figure 1)

Distribution zones may be distinguished because they are either fed by a pumping station sothat they are isolated from nearby zones by pressure or because they are fed from a servicereservoir which can markedly increase the retention time. Some distribution zones may varyseasonally due to supplementary sources being used at peak draw-off times while for otherzones the boundaries may vary due to changes in pressure or draw-off. Others may vary dueto the materials used in common sections of the distribution system.

The distribution zones selected for the Grading and the Standards are based on water quality

6

considerations and will not necessarily coincide with the distribution zones which the watersuppliers identify for operational and management purposes. The Ministry of Health expectsthat there would be more distribution zones based on hydraulics than there will be on waterquality.

Some community drinking-water supplies may comprise one distribution zone only. Somevery small community water supplies may not have a network of water mains. For example,drinking-water supplies at factories, rural schools and camping grounds may only have acommunal tap. Some small drinking-water supplies may receive their water from anothersupply by tanker which pumps the water into a storage tank.

Some water suppliers may receive their drinking-water from a water supply wholesaler viabulk mains.

VA

2 DETERMINATION OF COMPLIANCE

2.1 INTRODUCTIONThe first step in determining whether drinking-water complies with the Standards is to selectthe determinands which, because of their high public health risk, need to be monitored.Determinands have been divided into four Priority classes. To demonstrate compliance onlythose relatively few determinands which fall into the higher potential risk Priorities 1 and 2must be monitored. Monitoring of determinands in the lower potential risk Priorities 3 and4 is not essential to demonstrate compliance with the Standards which aim to minimisemonitoring costs without compromising public health.

Priority 1 determinands include only determinands of microbiological significance and applyto all drinking-water in New Zealand. Priority 2 determinands depend on the drinking-water supply and will be specified for each supply in the Register of Community Drinking-Water Supplies in New Zealand More details on the Priority classes and how to use themare provided in Section 2.3.2.

To comply with the Standards a determinand must be investigated according to themonitoring and analytical requirements given in Chapters 3, 4 and 5 for microbiological,chemical and radiological determinands respectively. Supply-specific monitoring programmesmust be designed for the determinands in Priorities 1 and 2.

Compliance is determined by comparing the results of these monitoring programmes againstthe Standards' compliance criteria over 12 months. Records must be kept for at least tenyears to enable trends to be detected and to establish the statistical significance of the results.

Apart from Priority 1 determinands, all other determinands could fall into Priorities 2, 3 or 4depending on the supply. The MAVs for all of the determinands are provided in a set oftables which covers all Priority classes (Chapter 13). The tables in Chapter 11 should be usedto select the appropriate information.

2.2 COMPLIANCE AND TRANSGRESSIONThe Drinking-Water Standards for New Zealand 1995 provide individual specifications foreach of microbiological, chemical and radiological compliance (see Chapters 3, 4 and 5respectively). A drinking-water supply complies with the Standards when the correctdeterminands are monitored according to the prescribed requirements and the results complywith the criteria. Compliance requirements for each of these categories are provided in therelevant chapters.

The terms compliance and non-compliance apply to the supply. They are not appropriate forindividual samples. Compliance is assessed on a running annual basis. In this way compliancecan be assessed at any time during the year using the previous twelve months' monitoringresults.

The term transgression applies to a single sample. If any determinand in a sample is belowits MAy, the sample meets the requirements of the Standards. A sample is said to transgressthe Standards when it does not meet the requirements of the Standards. Transgression ofthe Standards by a sample may not necessarily mean that the drinking-water supply itself is

in non-compliance. For example, compliance for faecal coliforms in a drinking-water supplydistribution zone requires that 98 percent of samples meet the standard on an annual basis.In this case, compliance of the supply with the Standards occurs even though two percent ofthe individual samples transgress. In the event of a sample transgressing the Standard,immediate action should be taken

2.3 SELECTION OF DETERMINANDS

2.3.1 INTRODUCTIONTo minimise the number of determinands which have to be monitored routinely in any specificdrinking-water supply, the determinands for which compliance has to be demonstrated havebeen grouped into four priority classes (see Section 2.3.2).

To demonstrate compliance with these Standards, it is necessary to comply with therequirements for Priority 1 and 2 determinands only. Priority 1 determinands apply to alldrinking-water. Priority 2 determinands will be determined initially from the results of theMinistry's national drinking-water surveillance programme and be published in the Registerof CommunityDrinking- Water Supplies in New Zealand. Additional monitoring of Priority3 and 4 determinands is at the discretion of the supplier, unless otherwise required by theMedical Officer of Health for public health reasons.

2.3.2 PRIORITY CLASSES FOR DRINKING-WATERDETERMINAN1DS

2.3.2.1 PRIORITY 1

The determinands in Priority 1 are determinands of health significance for all drinking-watersupplies in New Zealand. The priority 1 determinands are:

Faecal coliforms

Giardia

Cryptosporidium

Priority 1 includes determinands of microbiological significance whose absence fromdrinking-water must be demonstrated in order to demonstrate compliance with the Standards.Faecal coliforms are used to indicate possible faecal contamination and thus the presence ofpathogenic bacteria and viruses.

Free available chlorine measurements may be partially substituted for faecal coliformmonitoring. Information about monitoring and analytical requirements for faecal coliformsand free available chlorine is given in Chapter 3.

Modern diagnostic techniques show that Giardia and Cryptosporidium are more widespreadin natural waters than previously realised. Cryptosporidiosis is increasing rapidly in somedeveloped countries, and Cryptosporidium and Giardia are not always reliably removed byconventional water treatment.

Faecal coliforms cannot be used reliably as an indicator of the likely presence ofCryptosporidium and Giardia. There may be no correlation between the presence of faecal

9

coliforms and of pathogenic protozoa in drinking-water. Giardia and Cryptosporidiumoutbreaks frequently correlate with increases in the turbidity of water which has been treatedby flocculation and sand filtration.

In view of the serious public health effects of contamination of a drinking-water supply bythese protozoa, it is important that the likelihood of their presence in drinking-water isassessed. The most reliable methods currently available for direct determination of theseorganisms are expensive and require highly skilled staff. Also the organisms tend to appearsporadically, so that direct measurement techniques do not always give a representativeassessment of the true extent of their presence in a drinking-water supply.

If the water is subject to quiescent periods, the organisms may settle out so they are notpresent in the supernatant water. Disturbance of the sediments can resuspend the organisms,causing a sudden upsurge in their numbers.

Because of these difficulties, direct determination of the presence of Giardia andCryptosporidium is not used as a criterion of compliance with the Standards.

Alternative ways of assessing the likelihood of the absence of these protozoa are thereforeused. These are based on checking that the drinking-water has received a level of treatmentwhich has a high probability of having removed the organisms. In these Standards, the criteriaused are based on the use of turbidity to assess the effectiveness of conventional coagulation/filtration treatment; particle size to assess the effectiveness of treatment with cartridge filters;disinfection CA values to assess the adequacy of the contact time with disinfectants; or thatthe water has tome from secure wells which will be free from these organisms.

The specific compliance criteria for each of these situations are given in Chapter 3.

2.3.2.2 PRIORITY 2

a Chemical and radiological determinands which could be introduced into the drinking-wa ter supply by the treatment chemicals atlevels potentially sign ificant topublichealth(usually greater than 50percentMA 1'9.

b Chemical and radiological determinands of health significance which there is goodreason to suspectmaybe in the drinking-water supply atlevels potentially significant topublic health (usually greater than 50 percent MA 1'9.

c Micro-organisms of health significance which there is good reason to suspect may bepresent in the drinking-water supply.

The determinands in Priority 2 will be specific to the supply or the distribution zone, that isthe determinands which come into this category will depend on the characteristics of theparticular supply.

The determinands to be assigned to Priority 2 for a particular supply will be determined bythe Ministry of Health from information on the catchment, treatment processes, distributionsystem and surveillance data.

Priority 2a determinands will depend on the chemicals (and their impurities) used to treatthe raw water or added to the water supply and, to some extent, the degree of managementcontrol over their use. The likelihood a borderline candidate will be assigned to Priority 2arather than Priority 3 will be much greater if the treatment process is operated in such a waythat the concentration of the determinand varies greatly from time to time than if it ismaintained at a relatively constant concentration.

10

Some chemicals of health significance, for example copper sulphate for algal control, may beused only intermittently in the course of drinking-water treatment. In these situations thewater supplier must advise the Medical Officer of Health and consider an appropriatemonitoring programme. The Medical Officer of Health must also be advised of any long-term changes to the chemical treatment process so that the Register can be revised.

The frequency of monitoring of some Priority 2a determinands which can enter the drinking-water supply as impurities of water treatment chemicals may be diminished if water suppliersdemonstrate to the Medical Officer of Health's satisfaction (for example from flow rates andthe use of treatment chemicals with verified specifications) that the determinand cannot beintroduced into the drinking-water supply at concentrations greater than 50 percent MAy.

A determinand's placement in Priority 2 for a particular drinking-water supply will be listedin the Register of Community Drinking-Water Supplies in NewZealand, after consultationwith the water supplier, when monitoring information indicates that one of the above criteriaapplies. The monitoring requirement commences with the date of formal notification of thesupplier by the Ministry of Health, not with the publication date of the Register.

Lack of information on the concentrations of determinands in New Zealand's drinking-water supplies may initially delay the identification of all Priority 2 determinands so the listof determinands assigned to Priority 2 will be up-dated as more information becomesavailable.

A Priority 2 determinand may be relegated to Priority 3 or 4 with the consent of the Ministrywhen twelve successive monthly samples show concentrations below 50 percent MAy.

Information about the compliance criteria and the monitoring and analytical requirementsfor microbiological, chemical and radiological determinands are provided in Chapters 3, 4,and 5.

2.3.2.3 PRIORITY 3

a Chemical and radiological determinands of health significance arising from treatmentprocesses in amounts known not to exceed 5opercentALA V.

b Ch emical an d ra diological determinands of health significance which are not known tooccur in the drinking-water supply at greater than 50 percent MA V.

c Micro-organisms of health significance which there is no reason to suspect are presentin the drinking-water supply.

d Determinands of aesthetic significance known to occur in the drinking-water supply.Priority 3 includes those health significant determinands for which there is insufficientinformation about their occurrence in a specific drinking-water supply but which may occurat health-significant concentrations. Lack of information for the initial classification of health-significant determinands could mean some determinands will be classified as Priority 3initially when they should be Priority 2.

Health-significant determinands initially placed in Priority 3, will be moved to Priority 2 ifthey are found to meet one of the relevant criteria for that class. They will remain in Priority3 or be reduced to Priority 4 if there is sufficient evidence to indicate they are unlikely to bepresent in the supply.

Aesthetic determinands are classified as Priority 3 because they do not pose a direct threat topublic health. People however, judge drinking-water mainly by the aesthetic characteristics

11

of appearance, taste and smell, and an aesthetically unacceptable drinking-water supply maycause them to change to an alternative and potentially unsafe supply or treatment process.For this reason it is preferable that water supply authorities monitor these determinands,although this is not required to comply with the Standards.

2.3.2.4 PRIORITY 4

a Chemical andradiological determinands of health significance which are known not tobe likely to occur in the drinking-water supply.

b Micro-organisms of health significance which are known not to be likely to be presentin the drinking-water supply.

c Determinands of aesthetic significancenot known to occur in the drinking-watersupply.Priority 4 determinands for a specific supply will include those health significant or aestheticdeterminands for which there is sufficient information to consider it unlikely they would bepresent in a particular supply.

Some determinands, including some pesticides, will be Priority 4 for all New Zealand drinking-water because they are not used in this country at present. They are included in the tables toensure that MAVs are available should the situation change.

12

3 MICROBIOLOGICAL COMPLIANCE

3.1 INTRODUCTIONUnlike chemicals, micro-organisms such as bacteria, viruses and protozoa can multiply inthe body and cause acute illness. They may then spread from the infected person to thecommunity by person to person contact or faecal contamination of the water supply.Epidemics of disease may occur if this process continues unchecked. Microbiological publichealth issues of drinking-water supplies are, therefore, accorded higher priority than chemicalcontamination except when chemical contamination is acute.

For microbiological compliance with the Standards, the criteria set in this chapter for each ofthe determinands faecal coliforms, Giardia and Cryptospori di urn must be met.

3.2 RATIONALE FOR MICROBIOLOGICAL MAVSIt is impracticable to monitor water supplies for all potential human pathogens. Surrogateshave to be used to indicate possible contamination of the water supply with human andanimal waste, the most frequent source of health-significant contamination of water supplies.

3.2.1 FAECAL COLIFORMSThe indicator organisms chosen to indicate possible faecal contamination of drinking-waterare the thermotolerant coliforms, commonly known as faecal coliforms. The presence of faecalcoliforms in a water supply could mean that pathogenic bacteria, viruses and parasites arepresent. Faecal coliforms must be absent from drinking-water so are classed as Priority 1determinands.

Total coliforms, which include both faecal and environmental coliform bacteria, are sometimesused to monitor water quality. If total coliforms are used for drinking-water monitoringinstead of faecal coliforms, to demonstrate compliance with the Standards a positive totalcoliform result must be treated as though it were a faecal coliform result.

Water collected from surface water sources or shallow groundwater sources may contain micro-organisms which must be inactivated or removed before the water is suitable for drinking.This does not apply to water from those secure bores which are not directly affected by surfaceinfluences. These usually provide water free from faecal contamination.

Water used for drinking must be free from pathogenic organisms. The treatment processmust eliminate these. The presence of faecal coliforms is used as an indication that thetreatment process is faulty or inadequate or that the distribution system has beencontaminated.

Faecal coliforms should not be in water in the distribution zones. However, unlike the drinking-water leaving the treatment plant, whose microbiological quality is under the control of thetreatment plant management, the quality of drinking-water in the distribution zones may besubjected to contamination from a variety of influences. Some of these may arise from poormanagement practices, such as faulty reservoir construction and maintenance, poor sanitarypractices by water supply workers.

Other contamination sources arise from the water users themselves, such as either poorsanitation while making connections to the service or inadequate backflow prevention. Faecal

13

coliforms may, therefore, occasionally be found in the reticulation. Their occurrence theremust always be followed up.

If more than 0.2 mg/L free available chlorine is maintained in the drinking-water supplyreticulation, coliform bacteria are rarely, if ever, found. For this reason it may be permissibleto substitute monitoring of free available chlorine for some (but not all) of the faecal coliformmonitoring.

3.2.2. GIARDIA AND CRYPTOSPORIDIUMThe protozoa Giardia and Cryptosporidium occur in many New Zealand water sources. Theyare endemic in feral animals. Surface waters, including shallow groundwater, must beconsidered to be potentially contaminated. The risk associated with secure groundwater ismuch lower. Giardia and Cryptosporidium are pathogens which should be eliminated fromdrinking-water supplies. They are placed in Priority Class 1 because of their public healthsignificance.

The methods available for enumerating protozoan pathogens are expensive, time-consumingand inconclusive. They are not yet suitable for routine use. Until more rigorous proceduresare available, criteria based on the probability that the treatment process used will haveinactivated or removed any protozoa present will be used as criteria for compliance. Thesecriteria for particle size control, disinfection contact times, and turbidimetric assessment ofthe efficiency of coagulation and filtration are used in these Standards instead of directprotozoa enumeration.

The incidence of protozoa is reduced substantially when the water treatment coagulationfiltration process results in drinking-water with a turbidity below 0.1 NTU.

However, a compromise value of 0.5 NTU is used in the present Standards because the valueof 0.1 NTU may not be presently attainable by many New Zealand drinking-water supplies.The value of 0.1 NTU still remains the target. Avoidance of sudden increases in turbiditygreater than 0.2 NTU is also required by the compliance criteria as such increases often signala fall in filter efficiency which enables protozoa to breach the filtration barrier.

3.3 MICROBIOLOGICAL COMPLIANCE CRITERIASeparate criteria for compliance with the Standards are set for each of faecal coliforms, Giardiaand Cryptosporidium. These are provided in Sections 3.3.2-4.

In addition to these separate compliance criteria the general criteria listed below apply to allmicro-organisms in Section 3.3.1:

3.3.1 GENERAL MICROBIOLOGICAL CRITERIADrinking-water complies with the Standards if:

Microbiological Criterion 1

The sampling and analytical procedures comply with therequirements of these Standards.

and

14

Microbiological Criterion 2

The procedure outlined under Section 3.5: "Action to be takenwhen transgression of the microbiological MAV occurs" isfollowed and the action taken documented.

3.3.2 FAECAL COLIFORMSFaecal coliform compliance is assessed on the results of sampling over a 12 month periodand requires that a drinking-water supply meets the two faecal coliform compliance criteriagiven below. The same criteria apply to total coliforms or to E.coli if these are used asalternative indicator organisms.

3.3.2.1 FAECAL COLIFORM COMPLIANCE CRITERIA FORDRINKING-WATER LEAVING A TREATMENT PLANT

Faecal Coliform Criterion 1.

Drinking-water complies with the Standards if:

Either 1(a) No faecal coliforms are detectable in any 100 mL sample of drinking-water leaving the treatment plant sampled at the frequency specified inTable 3.1.

Or 1(b) Free available chlorine is monitored continuously in drinking-waterleaving the treatment plant and is maintained at at least 0.2 mg/L freeavailable chlorine at a pH less than 8.0 and turbidity less than 0.5 NTUwith a minimum contact time of 30 minutes and a down-time of lessthan 1 hour per week

3.3.2.2 FAECAL COLI FORM COMPLIANCE CRITERIA FORDRINKING-WATER IN A DISTRIBUTION ZONE

Faecal Coliform Compliance Criterion 2.


Either 2(a) At least 98 percent of samples taken in the distribution zone at thefrequency specified in Table 3.2 contain no faecal coliforms in 100 mL.

Or 2(b) When free available chlorine measurements are used as a partialsubstitute for faecal coliform monitoring in the distribution zone,samples taken at the frequency specified in Table 3.3 all contain morethan 0.2 mg/L of free available chlorine and have a pH less than 8.0 and

-turbidity less than 0.5 NTU;

andat least 98 percent of the faecal coliform samples taken in the distributionzone contain no faecal coliforms in 100 mL.

3.3.3 GIARDIA

3.3.3.1 GIARDIA COMPLIANCE CRITERIA FOR DRINKING-WATERLEAVING A TREATMENT PLANT

Giardia compliance criteria apply only to drinking-water leaving a treatment plant.

No Giardia compliance criteria are given for drinking-water in a distribution zone.

15


Giardia Compliance Criterion 1.

Either (a) (Criterion applicable to filtration without coagulation)

All drinking-water leaving the treatment plant has passed through a filterwhich removes all particles larger than 8im. The water supplier must beable to demonstrate that the plant is operating within specification.

Or(b) (Criterion applicable to chemical coagulation treatment)

95 percent of the turbidity measurements of drinking-water leaving thetreatment plant measured at the frequency specified in Table 3.4 arebelow 0.5 NTU and no sudden increases of more than 0.2 NTU occur inany 10 minute period.

Or(c) (Criterion applicable to disinfection)

Contact with disinfectants (chlorine, chlorine dioxide or ozone) ismaintained in accordance with C.t values given in Tables 12.1 - 12.7 atall times. Records must be kept to enable verification.

Or(d) (Criterion applicable to secure groundwater)

Water is continuously drawn from secure groundwater. The water mustbe demonstrated to meet the specification of secure groundwater givenin footnotes 1 and 2 to Table 3.1.

3.3.4 CRYPTOSPORIDIUM3.3.4.1 CRYPTOSPORIDIUM COMPLIANCE CRITERIA FOR DRINKING-

WATER LEAVING A TREATMENT PLANT

Cryptosporidium compliance criteria apply only to drinking-water leaving a treatment plant.

No Cryptospori di urn compliance criteria are given for drinking-water in a distribution zone.


Cryptosporidium Compliance Criterion 1.

Either (a)(Criterion applicable to filtration without coagulation)

All drinking-water leaving the treatment plant passes through a filterwhich removes all particles larger than 5pm. The water supplier must beable to demonstrate that the plant is operating within specification.

Or(b) (Criterion applicable to chemical coagulation treatment)

95 percent of the turbidity measurements of drinking-water leaving thetreatment plant measured at the frequency specified in Table 3.4 are below0.5 NTU and no sudden increases of more than 0.2 NTU occur in any 10minute period.

Or(c) (Criterion applicable to disinfection)

Contact with disinfectants (chlorine dioxide or ozone) is maintained inaccordance with disinfectant concentration and contact times given in

16

Table 12.8 at all times. Records must be kept to enable verification.

Or(d) (Criterion applicable to secure groundwater)

Water is continuously drawn from secure groundwater. The water mustbe demonstrated to meet the specification of secure groundwaterprovided in footnotes 1 and 2 to Table 3.1.

3.4 MICROBIOLOGICAL MONITORINGREQUIREMENTS

Priority 1 microbiological determinands must be monitored regularly and frequently at thetreatment plant and in the distribution zones to comply with the Standards.

The sampling frequencies specified for drinking-water leaving the treatment plant are basedon population, water source and disinfection.

Continuous measurement of free available chlorine may be substituted for faecal coliformtesting of drinking-water leaving the treatment plant provided that the final drinking-waterquality satisfies good disinfection practices of being maintained at a pH of less than 8.0, acontact time of at least 30 minutes and a final turbidity of less than 0.5 NTU.

The sampling frequency for faecal coliforms in the distribution zone is based on population.Samples must be collected at least weekly if a satisfactory degree of confidence in the meaningof the results is to be achieved. However, this requirement has been relaxed in the distributionzone (Table 3.2) for small communities because samples are taken weekly at the treatmentplant so that the overall frequency of sampling is sufficient to provide adequate statisticalpower.

Monitoring of free chlorine in the distribution zone may be substituted for up to 75 percentof the faecal coliform testing requirements provided that at least four free available chlorinetests are performed for each faecal coliform test which is omitted. Chlorine tests are requireddaily.

Giardia and Cryptosporidium are not usually monitored directly. The Standards offeralternative criteria for these, based on the type of treatment which the water receives.

Details about the monitoring programme should be deposited with the local Medical Officerof Health.

3.4.1 MICROBIOLOGICAL SAMPLING SITES

For Faecal Coliform Compliance Criterion 1, samples must be taken from drinking-waterleaving the treatment plant or, for untreated water, at the point of entry into thedistribution system. Samples should be collected after any storage prior to leaving thetreatment plant.

2 For Faecal Coliform Compliance Criterion 2, samples must be taken from sites giving arepresentative geographical coverage of the distribution zone to check for post-treatmentcontamination. To ensure that a distribution zone is evaluated adequately, sampling sitesshould be planned carefully, based on the characteristics of the distribution zone andwhat is known about age and state of repair of the various components, number ofhouseholds served by sections of the distribution system etc. The sampling plan, which

17

should be provided to the Medical Officer of Health, should include:

• fixed points such as pumping stations and reservoirs

• random locations throughout the distribution zone

• extremities of the distribution zone

• taps representing the mains water being supplied to houses

• extra sampling in the event of mains construction and maintenance.

3 For Giardia Criterion 1 (b)-(c) and Cryptosporidium Criterion 1 (b)-(c) samples must betaken from drinking-water leaving the treatment plant following any associated finalstorage at the treatment plant.

3.4.2 MICROBIOLOGICAL SAMPLING FREQUENCIES3.4.2.1 FAECAL COLI FORMS

3.4.2.1.1 FAECAL COLIFORMS IN DRINKING-WATER LEAVING A TREATMENTPLANT

Faecal coliform compliance criteria 1(a) and (b)

Table 3.1 details the minimum recommended sampling frequency for faecal coliforms indrinking-water leaving a treatment plant, depending on the nature of the original source andthe population served.

Table 3.1 Minimum recommended sampling frequency for faecal coilforms in drinking-water leaving a treatment plant.

Supply Type Faecal coliform minimum monitoring frequencyAll surface and non-secure groundwaterNone required if Continuous free available chlorinesupplies serving concentration is being monitored; is not less than 0.2more than 100,000 people.mg!L after a contact time of not less than 30 min at a

pH less than 8.0 and turbidity less than 0.5 NTU

Otherwise daily.

Chlorinated surface and non-secureNone required if continuous free available chlorinegroundwater supplies serving concentration is being monitored; is not less than 0.2500-100,000 people mg/L at a pH less than 8.0 and turbidity is less than 0.5

NTU after a contact time of no less than 30 mm.

Otherwise weekly.

All non-chlorinated surface and non-securegroundwater supplies serving Twice weekly500-100,000 peopleAll surface supplies and non-secure

Weeklygroundwater servingfewer than 500 people'Secure groundwater 1.2.3

Monthly(regardless of population) This may be reduced to every second month after 12

successive samples have shown zero faecal coliforms.

18

Notes to Table 3.11 Secure groundwater is defined as water contained beneath the land surface which isabstracted via a secure well-head or similarly proven structure. It must be not under the directinfluence of surface water or demonstrate any significant and rapid shifts in characteristicssuch as turbidity, temperature, conductivity or pH which closely correlate to anyclimatological, surface water conditions or land use practices. There must also be no insectsor other macro-organisms such as algae, organic debris or large diameter pathogens.Compliance with these requirements must have been reliably demonstrated.If any doubt remains that the groundwater is secure, a check should be made that the waterhas been in the aquifer for more than 1 year. (Seethe Guidelines forDrinking- Water QualityManagement for New Zealand 1995 for details).'The frequency of faecal coliform monitoring of drinking-water derived from securegroundwater must be increased from monthly to at least weekly when the source water qualitymay have changed, for example at peak abstraction during dry spells, following flooding ofthe recharge area, or when chemical or physical water quality changes have occurred.3For supplies serving fewer than 500 people, samples prescribed to be taken from drinking-water leaving the treatment plant may be taken from the distribution zone instead, if this ismore convenient, provided that sampling is done at the frequency specified and that no faecalcoliforms are found.'Monitoring additional to that required for compliance monitoring should be carried outafter installation of new mains or following repairs. -

3.4.2.1.2 FAECAL COLIFORMS IN A DISTRIBUTION ZONE

Faecal Coliform Compliance Criterion 2(a)(Faecal coliforms only)

The minimum recommended sampling frequencies for faecal coliforms in drinking-water inthe distribution zones are given in Table 3.2. Testing must be carried out on different daysthroughout the week.

The frequency of monitoring should be increased if there is a flood, emergency operation,interruption to the supply system or, when other circumstances may give rise to an increasedrisk of faecal contamination.

For populations between 500 and 5,000 the minimum sampling rate is one per week. If thedrinking-water is sampled less frequently than this, even if all samples contain no faecalcoliforms, there is inadequate statistical confidence that the supply is free from faecalcontamination.

While for small communities the minimum sampling frequency is set at one per month, alldrinking-water supplies should ideally be monitored at least weekly to provide improvedstatistical confidence in the results. The availability of simple proprietary Presence/Absencetest systems makes this possible.

19

Table 3.2 Minimum recommended sampling frequency for faecal coliforms in drinking-water in a distribution zone.

Population serviced'Minimum number of samples to be collected

less than 5001 per month

500-5,000 1 per week

5,000 - 100,0001 per week + 1 per month for each additional 5,000 above 5,000

100,000+ 6 per week +1 per month for each additional 10,000 above 100,0001 This must take seasonal fluctuations into account.2 Testing is to be carried out on different days throughout the week and must give a

representative geographical coverage of the distribution zone.

3.4.2.1.3 FREE AVAILABLE CHLORINE AND FAECAL COLIFORMS IN ADISTRIBUTION ZONE

Faecal Coliform Compliance Criterion 2(b) (Partial substitution by free available chlorine)

Free available chlorine monitoring may be substituted for up to 75 percent of the faecalcoliform tests required provided that at least four free available chlorine tests are performedfor each faecal coliform test omitted and chlorine monitoring is carried out daily.

The number of free available chlorine and faecal coliform tests needed is calculated from theformulae:

Number of free available = 0.75 x (number of faecal coliform tests required if nochlorine tests substitution with free available chlorine testing is done) x 4

Number of faecal= 0.25 x (number of faecal coliform tests required if nocoliform tests substitution with free available chlorine testing is done)

20

Table 3.3 Approximate minimum sampling frequency for faecal colifonns and free availablechlorine in a distribution zone.

ApproximatePopulationnumber offaecal coliformNumnber of samples per month if free

served in the distributionsamples required per monthavailable chlorine testing is partiallyzone if no substitution with freesubstituted for faecal coliform testing:

available chlorine testing isdone (from Table 3.2)Faecal coliformFree available

samples 1.2chlorine samples23

0-30,000 9 3 27

40,000 11 3 33

50,000 13 4 39

60,000 15 4 45

70,000 17 5 51

80,000 19 5 57

90,000 21 6 63

100,000 23 6 69

Results of the calculations rounded up to nearest whole number.2 Testing is to be carried out regularly throughout the week and must give a representative geographical

coverage of the distribution zone.See notes which follow.

Table 3.3 provides the results of calculations for a range of distribution zone populationsrounded-up to the nearest whole number.

Any interpolations to the table should be rounded up on a similar basis.3 Free available chlorine testing may be substituted for up to 75 percent of the faecal coliformtesting in distribution zones serving populations less than 30,000 provided that the minimummonitoring frequencies in Table 3.3 are adhered to.

The minimum monitoring frequency for free available chlorine is daily. For this reason theminimum monitoring frequency is constant when the number of persons served by thedistribution falls below 30,000.

Faecal coliform monitoring must be carried out regularly throughout the month on differentdays. The free available chlorine tests are to be conducted daily.

3.4.2.2GIARDIA

3.4.2.2.1GIARDIA IN DRINKING-WATER LEAVING A TREATMENT PLANT

Giardia Compliance Criteria

a(Criterion applicable to filtration without coagulation)

The filter must be in continuous operation.

b(Criterion applicable to chemical coagulation treatment)

21

Turbidity is used as a measure of the efficacy of the coagulation / filtration process.

Turbidity values tend to fluctuate and require continuous monitoring. Turbidity fluctuationscorresponding to filter events related to break-through of protozoa tend to occur at thebeginning and end of filter runs. Each filter should be monitored.

For compliance monitoring, the turbidity of drinking-water leaving the treatment plantmust be measured at the frequencies specified in Table 3.4 as a minimum.

Table 3.4 Minimum sampling frequency for turbidity in drinking-water leaving a treatmentplant, for Giardia Compliance Criterion lb

Population Served Frequency

More than 100,000 people Continuous

20,000 - 100,000 Twice a day

500 - 20,000 Daily

Less than 500 Weekly

c(Criterion applicable to disinfection)

Disinfection concentrations and flows must be monitored continuously to enable contacttimes (C.t) to be calculated. Refer to Tables 12.1-12.7.

d (Criterion applicable to water drawn from secure groundwater) -

The water must meet the faecal coliform criterion for secure groundwater given in Table3.1 and comply with the specification of secure groundwater (footnotes 1 and 2 to Table3.1) which must be checked every 3 months and whenever a major event occurs whichcould potentially affect the drinking-water quality.

e Direct measurement of Giardia.

Direct measurement of Giardia is not a compliance test. Direct measurement should beused to confirm suspected presence of Giardia but failure to find Giardia does notdemonstrate that drinking-water is free from Giardia. The frequency of testing is at thewater supplier's discretion, unless otherwise directed by the Medical Officer of Health.

3.4.2.3 CRYPTOSPORIDIUM

3.4.2.3.1 CRYPTOSPORIDIUM IN DRI N KING-WATER LEAVING A TREATMENT PLANT

Cryptosporidium Compliance Criteria

a(Criterion applicable to filtration without coagulation)

The filter must be in continuous operation.

b (Criterion applicable to chemical coagulation treatment)

Turbidity is used as a measure of the efficacy of the coagulation /filtration process.

22

Turbidity values fluctuate so require continuous monitoring. Turbidity fluctuations relate tothe break-through of protozoa and tend to occur at the beginning and end of filter runs.Each filter should be monitored.

The turbidity of the drinking-water leaving a treatment plant must be measured at thefrequencies specified in Table 3.4 as a minimum.

C(Criterion applicable to disinfection)

Disinfection concentrations and flows must be monitored continuously to enablecontact times to be calculated. Refer to Table 12.8.

d(Criterion applicable to secure groundwater)

The water must meet the faecal coliform criterion for secure groundwater given inTable 3.1 and comply with the specification of secure groundwater (footnotes 1 and 2to Table 3.1) which must be checked every 3 months and whenever a major event occurswhich could potentially affect the drinking-water quality.

eDirect measurement of CryptosporidiumDirect measurement of Cryptospori di urn is not a compliance test. Direct measurement shouldbe used to confirm suspected presence of Cryptosporidium but failure to findCryptospori di urn does not demonstrate drinking-water is free from Cryptospori di urn. Thefrequency of testing is at the supplier's discretion, unless otherwise directed by the MedicalOfficer of Health.

3.4.3 MICROBIOLOGICAL SAMPLING REQUIREMENTSA detailed discussion about sampling requirements for both faecal coliforms and free availablechlorine is given in Guidelines for Drinking-Water Quality Management in New Zealand1995. The discussion given here is specifically related to compliance requirements.

3.4.3.1 FAECAL COLIFORMS

Samples should be collected aseptically, in sterile bottles, using thiosulphate to dechlorinatethe sample if necessary. Ideally testing should take place within six hours of sample collectionand it must never be delayed more than 24 hours after collection. Samples should betransferred to the laboratory in a cool, dark container. If delivery time exceeds one hour,samples should be maintained at no more than 4°C but must not be frozen.

If an external laboratory is carrying out the analyses, the sampling procedures should beagreed with the laboratory beforehand.

3.4.3.2 FREE AVAILABLE CHLORINE

Measurement of free available chlorine must be made in the field.

3.4.3.3 TURBIDITY

Turbidity of the drinking-water leaving a treatment plant should be measured continuouslywhere possible.

In the case of samples being tested manually, these should be transported to the laboratoryas soon as possible, at the latest within 36 hours.

23

3.4.4 MICROBIOLOGICAL ANALYTICAL REQUIREMENTSLaboratories acceptable to the Ministry of Health and the Public Health Comission must beused for all analyses.

These laboratories will be expected to hold laboratory accreditation to the current version ofISO/JEC Guide 25 (General requirements for the competence of calibration and testinglaboratories), or equivalent, and to use quality control systems which provide evidence ofcompetency in testing.

In circumstances where accreditation is not feasible, alternative evidence of competence maybe accepted by the Ministry of Health and the Public Health Commission. This will requirecompliance with the relevant clauses of the current version of ISO/JEC Guide 25 to bedemonstrated.

More detailed information about analytical requirements for faecal coliforms, free availablechlorine, turbidity and particle size is given in Guidelines for Drinking-Water QualityManagement in NewZealand 1995.

3.4.4.1 BACTERIOLOGICAL REFEREE METHODS

The referee methods specified in these Standards will be regarded as the definitive methods.

Alternative methods are quite acceptable but must have been validated against the refereemethods. In the event of any dispute about differences in analytical results, results obtainedusing the referee method will be deemed to be correct.

Standard Methods for the Examination of Water and Wastewater, 18th edition, AmericanPublic Health Association, 1992.

9221 Multiple-tube fermentation technique for members of the coliform group.

9221 B Standard total coliform fermentation technique.

9221 E Faecal coliform procedure.

9222 Membrane filter technique for members of the coliform group.

9222 B Standard total coliform membrane filter procedure.

9222 D Faecal coliform membrane filter procedure.

For convenience Presence/Absence tests or other rapid methods for determining totalcoliforms, faecal coliforms or E.coliwhich are acceptable to the Ministry of Health and thePublic Health Commission for the purpose may be used for routine monitoring.

3.4.4.2 FREE AVAILABLE CHLORINE REFEREE METHOD

The referee method for measurement of free available chlorine is APHA 4500 Cl F DPD,ferrous ammonium sulphate titrimetric method. Other generally accepted field methods,eg, DPD tablets or powder in foil, and amperometric techniques may also be used as long asthey are calibrated against the referee method at least once every six months. The need tomeasure chlorine in the field makes it impracticable to expect an accredited laboratory toperform the analysis. However, the analyst making the measurement should be familiar withthe method and possible causes of inaccuracy.

Continuously monitoring chlorine analysers must be calibrated against the referee method

24

or a method which has been calibrated against the referee method at least as frequently as themanufacturer's recommendations.

3.4.4.3 TURBIDITY REFEREE METHOD

Continuous monitors must be calibrated at least as frequently as recommended by themanufacturer. Continuous turbidity monitors which do not use the nephelometric techniqueneed to be cross-calibrated with the manual Standards in NTU units.

To operate a turbidimeter with confidence at around the 0.5 NTU level will require aninstrument with a limit of detection better than 0.1 NTU and may require the use ofsophisticated calibration techniques.

2130 Turbidity by nephelometry.

Standard Methods for the Examination of Water and Wastewater, 18th edition, AmericanPublic Health Association, 1992.

3.5 ACTION TO BE TAKEN WHENTRANSGRESSION OF A MICROBIOLOGICALMAV OCCURS

When transgression of the microbiological Standards occurs there must be an immediateresponse. The action to be taken in the different circumstances is summarised below. Thisshould be documented in all cases.

3.5.1 FAECAL COLIFORM TRANSGRESSIONS

3.5.1.1 FAECAI. COLIFORMS IN DRINKING-WATER LEAVING ATREATMENT PLANT

Because contaminated drinking-water leaving the treatment plant can affect the wholecommunity, immediate action is required if a positive faecal coliform test is obtained (SeeFigure 3.1).

25

Figure 3.1 Response to faecal coliform contamination of drinking-water leaving a treatmentplant.

Routine monitoring offaecal coliforms

.' Faecalcoliformspresent )_J

N.?-' NO

YESACTION

Corrective actionSanitary surveyIncrease disinfection Inform M 0 H

Increase samplingDo faecal coliform count

ACTIONFaecal After faecal coliforms absent 3 days

coliforms still Reduce sampling to normalpresent Cease corrective action in

consultation with M 0 H

YES

ACTIONIntensify corrective actionConsider 'boil water" noticeConsult M 0 H

" Faecalcoliforms still

present __-

The response outlined in Figure 3.1 applies to total coliforms or to E. coil, when theseorganisms are used in place of faecal coliforms in the monitoring programme.

Corrective action to be taken includes inspecting the plant and equipment; checking and, ifnecessary, increasing the disinfection; sanitary survey; increasing sampling; and advising theMedical Officer of Health. Any remedial action indicated should be applied promptly. If thepositive resultwas obtained using a Presence/Absence or equivalent test, a second samplemust be collected within 12 hours and subjected to conventional testing procedures.

If repeat samples continue to be positive, the Medical Officer of Health should be consultedand remedial action, such as the issue of a "boil water" notice, should be carried out ifconsidered necessary. Corrective action should be intensified.

Corrective and remedial action should be continued until samples have tested coliform freefor three successive days.

26

3.5.1.2 FAECAL COLIFORMS IN . DRINKING-WATER IN ADISTRIBUTION ZONE

3.5.1.2.1 FAECAL COLI FORMS PRESENT

Figure 3.2 summarises the degree of response depending on the number of faecal coliformsfound.

• Figure 3.2 Response to faecal coliform contamination of a drinking-water supply• distribution zone.

Routine monitoring of

faecal coliforms I

' Faecal•••••.....coliforms present

? NO

YESDo faecal coliform count

Mor>

FCthan 1 saNO

positive o10

IMMEDIATE ACTIONConfirmatory samplingSanitary survey

YES

<FaecalIMMEDIATE ACTION 1Corrective actionSanitary surveyYESlifcoliforms stillI tillncrease disinfection resen,,Targetted sampling Inform M 0 H

NO

Faecalcoliforms still

present

YESIMMEDIATE ACTION

Increase corrective actionConsult M 0 H about remedialaction, e.g.Issue "Boil Water" noticeContinue increased sampling

ACTIONNOAfter faecal coliforms absent 3 days

Reduce sampling to normalCease corrective action inconsultation with M 0 H

NO

Faecalcoliforms still

presentYES

27

The response outlined in Figure 3.2 applies to total coliforms or E. coil, when these organismsare used in place of faecal coliforms in the monitoring programme.

When a positive result has been obtained using a Presence/Absence or equivalent test, a secondsample must be collected within 12 hours for analysis by a conventional test method.

Figure 3.2 summarises the successive stages of response, reflecting the fact that a distributionzone sample containing ten or more faecal coliforms per lOOmL or more than one sampletesting positive must be considered to be seriously contaminated.

The response includes resampling to confirm whether faecal coliforms are still present andascertaining the source of the contamination. For a heavy contamination (more than 10faecal coliforms per 100 mL) or asecond positive result, the Medical Officer of Health mustbe advised. Daily sampling should be continued until three successive clear days haveoccurred.

3.5.1.2.2 FREE AVAILABLE CHLORINE TOO LOW

If the free available chlorine is less than 0.2 mg/L more often than is prescribed in compliancecriterion 2b, full monitoring of faecal coliforms according to Table 3.2 should be carried outin addition to the free available chlorine monitoring schedule. The free available chlorinemonitoring regime may be re-instated when the level of free available chlorine hascontinuously met the requirements of the Standards for one week.

3.5.2 GIARDIA AND CRYPTOSPORIDIUM TRANSGRESSIONS3.5.2.1 TURBIDITY IN DRINKING-WATER LEAVING ATREATMENT

PLANT

The reason for sudden increases or transgressions should be investigated immediately.

28

-- Figure 33 Response to turbidity transgression for drinking-water leaving a treatment plant.

Routine turbiditymonitoring 11 1Turbidity

greater than 0.5NTUor NO

Turbidity increasegreater than 0.2 NTU

in 10 minutes?

YES

ACTIONCheck and adjust:

- coagulation conditions-clarifier and filter operation

Resamole 5 times oer hour

Anysamples more than

0.5 NTU or turbidity increasemore than 02T>

in

YES

ACTION:Review and modify rateof change of flowthrough plant

Anysamples more than

0.5 NTU or turbidity increasemore than 0.2 NTU in

minu

YES

ACTION:Thoroughly investigate alltreatment steps.Undertake protozoa samplingNotify M 0 H

NO

NO

0

29

Investigation should consider the effect of possible occurrences in the catchment, and theneed for any remedial action involving coagulant dose adjustment, floc carryover, filtrationmethod of operation, individual filter condition; remedying short-circuiting in clear waterstorage, adjusting disinfection, etc. The frequency of testing the drinking-water leaving thetreatment plant should be increased until the turbidity has returned to below 0.5 NTU.

Figure 3.3 shows the steps to be followed in response to turbidity transgression for drinking-water leaving a treatment plant.

3.5.2.2DISINFECTION CONTACT TIME

If the specified disinfection CA value has not been achieved either the disinfectant dose rateor the retention time or both should be increased. Where this does not achieve the C.t valuerequired by the Standards, the Medical Officer of Health should be advised.

Figure 3.4 Response to disinfectant C.t transgression for drinking-water leaving a treatmentplant.

Routine Disinfectantand flow monitoring

C.t. NObelow the valueiiven in Table 12

YES

ACTIONCheck and adjust:

- disinfectant dose- contact time

Resam ple 5 times per hour

Anysamples still failC.t specification-?

YESACTION:

Readjust disinfectant dose,Check contact tank operation.Resite disinfection injectionNotify MOH.

YES< Any

samples still fail-C.t specification

30

4 CHEMICAL COMPLIANCE

4.1 INTRODUCTIONChemical substances can have two health effects: short-term or acute and long-term or chronic.The-concentrations of chemicals in drinking-waters are generally sufficiently low that theydo not produce acute effects. The main health concern about chemical contaminants indrinking-water relates to their long-term effects. The MAV for a determinand represents theconcentration of a determinand which, on the basis of current knowledge, does not result inany significant risk to the health of a person over a lifetime of consumption.

Chemical constituents of drinking-waters may come from:

the source water

the treatment process

the distribution system.

Contamination of source waters may occur from natural, industrial, domestic, agriculturaland recreational sources. Examples of health-significant determinands which have importantnatural sources in some New Zealand waters include arsenic, fluoride and boron. A potentialsource of contamination of source waters from agricultural practices is the use of pesticides.

Drinking-water can also be contaminated by health-significant substances through the watertreatment process. Disinfection by-products are produced over a range of concentrations inchlorinated supplies, particularly those sourced from coloured surface waters. In addition,some health-significant determinands such as acrylamide, epichiOrohydrin and various otherimpurities may be introduced with the water treatment chemicals themselves. A number ofhealth-significant determinands may be leached from materials used in the distributionsystem.

The following sections detail the monitoring requirements necessary to demonstratecompliance for those determinands which have been designated to be in Priority 2 for aparticular supply.

4.2 RATIONALE FOR CHEMICAL MAVSNearly all of the Maximum Acceptable Values (MAVs) for the determinands covered in theseStandards are based on the World Health Organization publication Guidelines forDrinking-Water Quality 1993. The rationale behind the derivation of the MAVs and informationconcerning health considerations is given in the Guidelines for Drinking-Water QualityManagement for NewZeaiand 1995.

Two methods were used to derive MAVs for chemical determinands of health significance.MAVs for carcinogenic substances whose genotoxic mechanism theoretically does not have athreshold have been derived using hypothetical mathematical models based on animal data.These are generally conservative and err on the side of caution. For most carcinogenicsubstances, the MAV in these Standards is the concentration of the substance in drinking-water which has been estimated to cause one additional incidence of cancer in a populationof 100,000 people ingesting water containing the substance at this concentration for seventyyears. For other chemicals, the MAV has been calculated using a Tolerable Daily Intake (TDI)

31

approach which is based on the general belief that there is a dose below which no adverseeffects will occur. The experimentally determined No Observable Adverse Effect Levels(NOAELs) or Lowest Observable Adverse Effect Levels (LOAELs) are used to calculate theMAV. MAVs calculated in this manner represent a concentration associated with no significantrisk from a lifetime of consumption.

The MAVs for chemical determinands were calculated separately for individual substances,without specific consideration of the potential for interaction of each substance with othercompounds present. However, the large margin of safety incorporated in the majority of theMAVs is considered to be sufficient to allow for most such potential interactions.

4.3 COMPLIANCE CRITERIA FOR CHEMICALSThere are two types of Priority 2 chemical determinands:

• Priority 2a: Chemical determinands which could be introduced into the drinking-water supply by the treatment chemicals at levels potentially significant to public health(usually greater than 50 percent MAy). Priority 2a does not include disinfection by-products or determinands introduced into the drinking-water from piping or otherconstruction materials.

Priority 2b: Chemical determinands of health significance, other than thoseintroduced by the treatment chemicals, which there is good reason to suspect to be inthe drinking-water supply at levels potentially significant to public health (usually greaterthan 50 percent MAy). Priority 2b includes any disinfection by-products anddeterminands introduced into the drinking-water from piping or other constructionmaterials.

Only those determinands specified by the Ministry of Health as Priority 2 determinands forthe drinking-water supply under consideration need to be monitored to establish compliancewith the Standards. The need to monitor Priority 2 determinands may relate to individualdistribution zones, or to the treatment plant if it affects more than one zone. Assignment ofdeterminands into Priority 2 will be based on a knowledge of sources of health-significantdeterminands in the catchment, treatment processes and distribution system, and frommonitoring. Priority 2 determinands for a given supply will be notified directly to the managerof that supply and listed in the Register of Community Drinking-Water Supplies in NewZealand published by the Ministry of Health. The requirement to monitor Priority 2determinands commences with the date of formal notification of the supplier by the Ministryof Health, not that of the Register's publication date.

Figure 4.1 illustrates how to establish compliance of Priority 2 chemical determinands withthe Standards.

Chemical compliance is assessed on the results of sampling carried out over a 12 monthperiod. The following compliance criteria must be met:

1. Samples are taken at the required sites and frequency for the determinand in question.

2. The sampling and analytical techniques comply with the requirements of theseStandards.

3. For determinands which are sampled either weekly or monthly, no samples musttransgress the MAV during 12 months of monitoring.

32

4. Where more than one determinand, which causes similar toxicological effects, is present,for compliance with the Standards the sum of the ratios of the concentration of eachdeterminand to its respective MAV shall not exceed one.

5. The procedure outlined in Section 4.5 "Transgression of the MAY' for chemicals isfollowed and results and actions documented.

MAVs for chemical determinands of health significance are given in Tables 13.2-13.4. Forcarcinogenic determinands, the tables also specify the risk of ingesting the substance at theMAV for seventy years. Guideline values for aesthetic determinands are given in Table 13.6.

If there are no transgressions of the MAV during 12 months of sampling monthly the Ministrycan be 95 percent confident that the drinking-water complies with the Standards for 78 percentof the time.

A minimum of 58 samples, none of which transgresses the MAy, is required before theMinistry can be 95 percent confident that the supply complies with the Standards for 95percent of the time. No more than one transgression in 93 samples is acceptable if the Ministryis to remain 95 percent confident that the drinking-water complies with the Standards for 95percent of the time.

A Priority 2 determinand may be relegated to Priority 3 or 4, with the consent of the Ministryof Health, when 12 successive monthly samples show concentrations below 50 percent ofthe MAy.

Monitoring of Priority 3 determinands is at the water supplier's discretion. Aestheticdeterminands appear in Priority 3. These determinands do not have any direct healthsignificance and are discussed in the Guidelines for Drinking-Water Quality Managementfor New Zealand 1995. The guideline values for aesthetic determinands are included in theStandards (Table 13.6) because they are still an important indicator of the suitability of thequality of drinking-water.

4.4 CHEMICAL MONITORING REQUIREMENTSMonitoring requirements are summarised in Table 4.1 and are discussed below. A fullerdiscussion is in the Guidelines for Drinking-Water Quality Management for New Zealand1995.

4.4.1 CHEMICAL SAMPLING SITES

Priority 2a determinands

Priority 2a determinands are introduced with water treatment chemicals. Sampling shouldbe carried out in the drinking-water leaving the treatment plant, except for chlorine, whichshould be monitored in the distribution zone.

Priority 2b deterrninands

Priority 2b determinands, which include disinfection by-products and products derived fromconstruction materials, have a variety of sources. The sampling site location will depend onthe determinand in question. Because disinfection by-products continue to react in thedistribution system, they have been included with the Priority 2b determinands.

Priority 2b determinands can be classified into two main types:

33

Type 1: substances whose concentration is unlikely to vary during distribution;

Type 2: substances whose concentration may vary during distribution.

Priority 2b Type 1 determinands, whose concentration will not be affected by the distributionsystem, should ideally be monitored in the drinking-water leaving the treatment plant.Samples may be taken from the distribution zone if this is more convenient.

Priority 2b Type 2 determinands, which have a source in the distribution system, or whichreact in or with it, must be sampled from the distribution zone only.

Tables 11.1 to 11.3 indicate which sampling site(s) are appropriate for Priority 2b chemicaldeterminands. A tick in the "DZ" column indicates the sample must be taken from thedistribution zone only. Ticks in both the "TW" and "DZ" columns indicate that thedeterminands can be sampled from either the drinking-water at the treatment plant or in thedistribution zone.

Distribution zone sampling sites should be selected to be either representative of the waterquality in the distribution zone, or appropriate for the determinand in question, unlessotherwise specified by the public health agencies. For example, samples for disinfection by-products should be collected near the ends of the distribution system. Some sampling shouldbe carried out at fixed sites so that water quality trends can be followed over time.

Further sampling at random sites may be useful to investigate:

the effects of different reticulation materials

the effects of spatial and temporal effects on drinking-water quality

the representativeness of the fixed sites selected.

34

Figure 4.1 Establishing compliance of Priority 2 determinands with the Standards.

Identification of a determinand as Priority 2(When the concentration of a Priority 3 determinand

exceeds 50% MAy)

Establish and document the monitoring programme-sampling sites Table 4.1-frequency of monitoringTable 4.1-sampling and analytical requirements

(Sections 4.4.3 & 4.4.4 Table 13)Provide the Medical Officer of Health with details ii

35

4.4.2 CHEMICAL SAMPLING FREQUENCIESSampling frequencies are summarised in Table 4.1. Sampling frequency requirements forPriority 2a and 2b determinands are given in more detail below.

Priority 2a determinandsSome health-significant determinands may either be used in water treatment or be introducedinto the drinking-water supply as the result of their presence as impurities in chemicals usedin water treatment. Management practices have the potential to cause much more extremevariations in the concentrations of these substances than would occur naturally in the sourcewaters.

Health-significant chemicals used for water treatment include fluoride and chlorine.

For compliance with the Standards, fluoridated drinking-water supplies should be monitoredfor fluoride at least weekly. For control of fluoride dosage for oral health purposes, therecommendations of the appropriate authority should be followed.

Some water suppliers may choose to monitor the free chlorine content of the drinking-waterentering the distribution system; those who do not must monitor the chlorine concentrationat least weekly if chlorine becomes a Priority 2a determinand.

Well-managed drinking-water supplies will undergo process monitoring of thesedeterminands more frequently than is specified above. These process monitoring results canbe used to demonstrate compliance.

The minimum monitoring frequency required for impurities of health significance introducedwith water treatment chemicals is monthly if they become a Priority 2a determinand. Watersuppliers will be able to calculate whether impurities from the treatment chemicals are likelyto approach 50 percent of the MAV from their maximum dose rates and data from verifiablecertification covering each batch from each source of the chemical used.

A change in operating conditions can affect the concentrations of determinands of healthsignificance introduced by the treatment process. Additional sampling and analysis may benecessary when:

• The concentration of a determinand increases in the raw water to the extent that 50percent of the MAV may be exceeded. The effects of recycling washwater should beconsidered.

•The chemicals used do not have a validated certificate of quality.

• A chemical of health significance is dosed into the water upstream of the treatmentprocess in order to control water quality problems. The Medical Officer of Health mustalso be advised.

•After filter backwashes which could affect the concentration of the determinand in thedrinking-water (for example, manganese).

Priority 2b determinandsPriority 2b, Type 1 determinands, should be monitored monthly at the minimum.Priority 2b, Type 2 determinands, whose concentration may change in the distribution system,should be monitored at selected fixed site(s) at least once a month and sufficient extra randomsamples should be collected throughout the year to detect any spatial variability and effectsfrom the distribution system.

36

Table 4.1 Monitoring requirements for Priority 2a and 2b determinands.

IPriority Sampling SiteNumber of SamplingMinimumMonitoringLocations Sites frequency

Priority 2a Drinking-water 1 Fluoride andleaving the treatment chlorine weeklyplant (except for All others,chlorine, which ismonitored in the Monthlydistribution-zone)

Priority 2b, Type 1

Priority 2b, Type 2

Drinking-waterleaving the treatmentplant*

Distribution zone

1

Sufficient siteschosen to reflect theproblems associatedwith thedeterminand inrelation to thematerials used, andreaction time fordisinfection by-products

Monthly

Monthl' at each site;plus sufficientrandom samples

* May also be monitored in the distribution zone if this is more convenientx-

4.4.3 CHEMICAL SAMPLING REQUIREMENTSThere are two aspects to ensuring that the composition of the water reaching the laboratoryis unchanged from the water composition at the time of sampling: correct -sampling andcorrect preservation.

The sampling container, sample preservation and storage specifications should be those givenin the methods specified in Chapter 13. Detail on sampling methods and procedures is givenin Guidelines for Drinking- Water Quality Management for New Zealand 1995.

Before starting a monitoring programme these methods and procedures should be confirmedwith the laboratory which is to carry out the analyses.

4.4.4 CHEMICAL ANALYTICAL REQUIREMENTSFor consistency of application of the Standards, the laboratory which analyses the watersamples should be on the list of water analysis laboratories acceptable to the public healthagencies and will be participating in a programme of interlaboratory calibration.

These laboratories will use either the referee methods specified in Chapter 13 or other methodswhich have been calibrated against the referee method. Insituations where there is contentionthe results obtained using the referee method will be deemed to be correct.

The laboratory's statistically determined detection limits (method detection limit) for eachdeterminand should be ideally one fifth, or less, of the MAV for that determinand. This maynot be possible for all determinands.

37

4.5 TRANSGRESSION OF A CHEMICAL MAyTransgression of the MAV occurs when the concentration of a determinand in a sampleexceeds the MAy. Transgression of the MAV by a single sample will not necessarily result inthe drinking-water supply failing to comply with the Standards. The definition of compliancein some cases permits a small number of transgressions to occur, without breachingcompliance. To minimise any risks to public health however, immediate action must be taken.

After a transgression has occurred the Medical Officer of Health should be advisedimmediately, the supply/site resampled, the cause of the transgression investigated andappropriate action taken.

Weekly sampling should continue until the MAV is not exceeded in three successive analyses.All incidents of transgression must be recorded, including monitoring results, action takenand outcomes.

The suitability of a drinking-water supply may need to be questioned if it suffers frompersistent transgressions.

38

5. RADIOLOGICAL COMPLIANCE

5.1 INTRODUCTIONRadioactivity in drinking-water is derived from the leaching of radionuclides from rocks andsoils and the deposition of radionuclides from the atmosphere. Naturally-occurringradionuclides from these two sources account almost entirely for the radioactivity present inNew Zealand drinking-water. Traces of artificial radioactive fallout from above-ground nuclearweapons tests (conducted up to 1980) are detectable in the environment but their combinedcontribution to drinking-water radioactivity is insignificant. The Drinking- Water Standardsfor New Zealand 1995 however, apply to radioactivity from all sources, artificial and natural.

Natural radioactivity in water is due mainly to dissolved uranium-238 and its decay productsuranium-234, radium-226 and radon-222 (and radon decay products); radium-228 from thethorium-232 decay series; and potassium-40 (a radioactive isotope of potassium with a naturalabundance of 0.0118 percent).The radioactivity of water therefore varies with the compositionof rocks and soils in the collection area. Other radionuclides in the uranium and thoriumdecay series, including isotopes of thorium and lead, have such low solubilities that they donot make a significant contribution to drinking-water radioactivity. Potassium-40 is nottakeninto account radiologically because potassium levels in the body are in a state of equilibriumand dietary potassium levels therefore do not significantly affect internal radiation exposure.

5.2 RATIONALE FOR RADIOLOGICAL MAVS.All living organisms are exposed to radiation from natural sources including cosmic radiationfrom outer space; external radiation from natural radionuclides (uranium and thorium andtheir decay products, and potassium-40) present in soils, rocks and building materials; andinternal radiation due to potassium-40 and inhaled radionuclides, particularly radon decayproducts. Natural radiation exposure varies regionally as the compositions of soils and rockschange, and increases with altitude as cosmic radiation intensity increases, and nothing canbe done to prevent exposure.

In terms of health significance, radioactive materials in drinking-water can be divided intotwo categories: alpha-particle emitters and beta-particle emitters. The ingestion of eitherresults in internal radiation exposure but alpha-particle emitting radionuclides are the morehazardous because of the greaterenergies of alpha particles. For this reason the Standardsconsider the two types of materials separately.

The Drinking- Water Standards for New Zealand 1995 adopt MAVs for total concentrationsof alpha-emitting and beta-emitting radionuclides, excluding radon-222 and potassium-40,which would limit the annual radiation dose resulting from the consumption of two litres ofwater per day to less than five percent of the average annual radiation dose due to all naturalsources.

The MAVs are deliberately conservative, such that if the natural radionuclides uranium-238,uranium-234, radium-226 and radium-228 were all present in drinking-water at the MAVlevel, the annual radiation dose would still be less than five percent of the total annual naturaldose.

39

This approach is consistent with drinking-water standards for radioactivity proposed by theWorld Health Organization and in Australia.

5.3 RADIOLOGICAL COMPLIANCE CRITERIAThe MAVs for alpha-emitting and beta-emitting radionuclides are:

total alpha activity: 0.10 becquerel per litre, excluding radon

total beta activity: 0.50 becquerel per litre, excluding potassium-40.

Radon is a gas which may be present in artesian waters following underground dissolution.In household use, radon discharges rapidly from water and the main exposure route isinhalation. Normal dietary considerations therefore do not apply. Taking into accountinhalation modelling and radon water-atmosphere equilibration studies, the recommendedMAV for radon is:

Radon-222 concentration: 100 becquerels per litre.

5.4 RADIOLOGICAL MONITORINGREQUIREMENTS

A nation-wide survey of radioactivity in drinking-water, conducted by the National RadiationLaboratory in 1980, indicated that radioactivity levels in all drinking-water supplies servingpopulation groups of 5,000 or more were below 50 percent of the MAVs for alpha- and beta-radioactivity and radon. Drinking-water radioactivity is thus classed as Priority 3 so regularroutine testing of public drinking-water supplies is not required.

Water from new underground sources should however, be tested before connection to publicdrinking-water supplies.

If radiological sampling of water is contemplated the Ministry of Health's National RadiationLaboratory should be consulted.

5.5 TRANSGRESSION OF A RADIOLOGICAL MAyIf the radioactivity of a drinking-water supply exceeds 50 percent of the MAY, the supply isto be analysed for contributing radioactive materials and an assessment made of theirradiological significance by the Ministry of Health's National Radiation Laboratory (NRL).

NRL provides both analytical and radiological advisory services appropriate for water-testing.

If the alpha-radioactivity exceeds 0.1 becquerel per litre (excluding radon), the water shouldbe analysed for uranium-238, uranium-234 and radium-226 and a radiological assessmentundertaken. If the beta-radioactivity exceeds 0.5 becquerel per litre (excluding potassium-40), the water should be analysed for radium-228 and any other beta-emitting radionuclideswhich may be present, and a radiological assessment undertaken.

If the radiological MAV is transgressed the NRL will advise the Medical Officer of Health andthe water supplier of the remedial action to be taken.

40

6 RECORDS

Records should be kept of the results of monitoring drinking-water determinands.

The records will be necessary to demonstrate that the Drinking-Water Standards for NewZealand 1995 are being complied with. It is an essential requirement for the public healthgrading of drinking-water supplies.

The records should include the following information:

1. The name of the supply, treatment plant(s) and distribution zone(s) to which theinformation relates. The unique reference number listed in the Register of CommunityDrinking-Water Supplies in New Zealand should be included. If the water supply hasnot been assigned reference numbers, these should be obtained from the Ministry ofHealth.

2. The treatment processes in operation at the beginning of the year being reported, andany modifications that changed the process during the year.

3. The determinands being monitored for the year, and the reasons for the omission ofthose Priority 1 and Priority 2 determinands not being monitored, with corroboratingdata where appropriate.

4. The sampling frequency for each determinand, the dates and times on which themeasurements were made, the sampling site location and the analytical results.

5. Any corrective action taken, either as a result of the level of a determinand exceedingthe MAy, or because it was considered necessary by the water supplier.

6. The laboratory used for the analyses.

7. Any re-evaluation of the operational programme undertaken, and the reasons for thisbeing done. Notes concerning treatment modification are included above, but changesin the operation or the materials used in the reticulation should also be noted whereappropriate.

8. Operational records, including process changes and operational monitoring.

9. Staff supervisors and operators, together with details of their relevant qualificationsand experience.

Proper internal documentation of the monitoring programme, as detailed in the Guidelinesfor Drinking- Water QualityManagementforNewZealandl99s will enable suppliers to collatethis information easily. Records must be kept for a minimum of ten years and must be madeavailable to designated health officers as required.

This information will assist in determining whether a drinking-water supply complies withthe Standards and in providing an indication of the extent to which the target of providingsafe drinking-water throughout New Zealand is being achieved. It will also alert the healthauthorities to any persistent problems which may exist.

41

7 DEFINITIONS

Applying to terms used in Drinking-Water Standards for NewZealand 1995.

acute level The dose of a determinand which causes an effect after a singleor short-term exposure.

aesthetic determinandThe constituent or property of the water which affects the taste,odour, colour, clarity or general appearance of the water.

aggressiveness The tendency of a water to corrode water supply pipes andfittings. In these Standards the Langelier Saturation Index (LSI)is used to quantify aggressiveness.

See determinand.

Radioactive activity of 1 nuclear transformation per second.

A water supplier who sells drinking-water to another supplier(eg a territorial local authority) for distribution.

The valley upstream of the raw water abstraction point, or theaquifer and recharge zone of a groundwater system.

analyte

Becquerel

bulk supplier

catchment

chloramines Compounds which may form through the reaction of freeavailable chlorine with nitrogen compounds. Chloraminesformed from the reaction of FAC with ammonia aremonochloramine, dichloramine or trichloramine.

chronic level

coliform organisms

committed effective dose(radioactivity)

The dose of a determined which causes an effect after long termexposure.

The bacteria used as indicators that organic, possibly faecal,contamination of the water may have occurred. Sometimesreferred to as total coliforms.

The lifetime sum of the effective dose (50 years for adults: 70years intake to age 70 or children).

community drinking-water A publicity or privately owned drinking-water supply whichsupply serves 25 or more people for at least 60 days per year.

compliance A drinking-water supply is said to be "in compliance with theStandards" when the results of monitoring of priority 1 and 2determinands show that the water supply satisfies therequirements of the Drinking-Water Standards for NewZealand 1995.

confidence interval

A condition which must be satisfied in order to achievecompliance.

Any monitoring conducted to test whether a drinking-watersupply complied with the Drinking-Water Standards for NewZealand 1995.

An interval which has a prescribed probability of containingthe true value of an unknown parameter.

compliance criterion

compliance monitoring

42

confidence level

The probability that an assertion about the value of apopulation parameter is correct.

confidence limits The upper and lower boundaries of the confidence interval.

contaminant

A substance or organism in the water which can causeundesirable public health or aesthetic effects.

C.t values The product of disinfectant dose (in mg/L) and contact time(in minutes) required to cause a specified level of inactivationof a micro-organism. This is a measure of the exposure to thedisinfectant.

data sheets The section in the Guidelines which lists the sources,occurrence, removal process, analysis, health effects, and thederivation of the MAVs of determinands.

designated officer A Health Protection Officer or Medical Officer of Healthdesignated by the Director-General of Health, pursuant toSection 7A(4) of the Health Act 1956 (as inserted by the HealthAmendment Act 1993).

direction limit

disinfectant C.t values

disinfection

disinfection by-products

distribution system

See method detection limit.

See C.t values.

The process used to inactivate the micro-organisms in thedrinking-water supply.

Contaminants produced in the drinking-water supply as by-products of the disinfection process.

All the trunk main, storage, distribution system componentswhich follow a treatment plant and any post-treatment storagefacility at the treatment plant.

distribution zone The part of the drinking-water supply network within whichall consumers receive drinking-water of identical quality, fromthe same or similar sources, with the same treatment andusually at the same pressure. It is part of the supply networkwhich is clearly separated from other parts of the network,generally by location, but in some cases by the layout of thepipe network.

For example, in a large city, the central city area may form onezone, with outlying suburbs forming separate zones, or, in asmall town, the system may be divided into two distinct areas.The main purpose of assigning zones is to separately gradeparts of the system with distinctly different characteristics.

down-time The length of time for which a process in the treatment plantis out of action.

drinking-water Standards A yardstick to assess the quality of drinking-water. At the timeof publication of the Drinking-Water Standards for NewZealand 1995, they do not carry any statutory status.

43

E.coli=Escherichia coli A bacterium used as an indicator that faecal contamination ofthe water has almost certainly occurred, and that, therefore,there is a possibility that pathogens are present.

effèctive dose (radioactivity) The effective dose is the equivalent, uniform, wholebody dosehaving the same radiation health detriment as the actual dosedistributed among the various organs of the body, with the unitsievert or millisievert (mSv). (See also Committed effectivedose.)

enteric viruses Viruses occurring in the digestive system and found in faecesof human or animal origin.

exceedence The occurrence of a determinand in a sample at a concentrationgreater than the MAV.

faecal coliforms

Bacteria used to indicate that faecal contamination has(= thermotolerant coliforms) probably occurred and that the water needs to be treated given

the likelihood that pathogens are present.

free available chlorine

guideline

guideline value

health detriment

indicator organism

limit of detection

The chlorine present in a chlorinated water in the form ofhypochlorous acid and hypochlorite ion.

A preferred course of action, process, or procedure.

Acceptable concentrations of determinands which indicatewhen the concentration of the determinand is high enough tohave aesthetic significance.

An adverse effect on health.

An organism, eg a faecal coliform, which is monitored toindicate the presence of faecal contamination.

See method detection limit.

Langelier Saturation Index A measure of the "aggressiveness" of a water. The Langelier(LSD Saturation Index (LSI) is defined as the actual pH of the water

minus the pH at which the water will be in equilibrium withsolid calcium carbonate.

Lowest Observed AdverseThe lowest dose of a contaminant at which a statisticallyEffect Level (LOAEL)significant adverse effect has been observed in a group of test

animals.

Comment: Such a value would only be used to establish ahuman TDI when an appropriate NOAEL was not able to bedetermined. In the event that a LOAEL (rather than a NOAEL)is used as the basis for a TDI, it is likely that a higher uncertaintyfactor would be employed.

LSI

See: Langelier Saturation Index.

Maximum Acceptable Value The concentration of a determinand below which the presence(MAy) of the determinand does not result in any significant risk to a

consumer over a lifetime of consumption. For carcinogenicchemicals, the MAVs set in these Standards generally represent

44

a risk of one additional incidence of cancer per 100,000 peopleingesting the water at the concentration ofthe MAV for seventyyears.

Method detection limit.

An officer designated by the Director-General of Health inaccordance with the provisions of the Health Act 1956.

MDL

Medical Officer of Health

method detection limit The constituent concentration which. when processed throughthe complete analytical method, produces a signal with a 99percent probability that it is different from the blank. Sevenreplicate measurements of a solution containing the

- determinant of interest at a concentration near to the estimatedMDL are used to calculate the standard deviation (s). The MDLis 3.14 xs.

micro-organism Includes viruses, bacteria, protozoa, algae and helminths.

MOH

Medical Officer of Health.

monitoring The sampling and analysis of a drinking-water supply to testfor compliance with the Standards or for process control, bydetecting changes in the concentrations of its constituentdeterminands or deviations of these from target values.Monitoring is usually carried out by the water supplier.

non-secure groundwaterGroundwater which does not meet the definition of securegroundwater.

No Observed Adverse Effect The dose of a contaminant at which no diverse effect has beenLevel (NOAEL)observed on a test animal.

parameter A co-efficient or factor in an expression or equation used toprocess data.

parasites Refers to Giardia and Cryptospori di urn in this document.

pathogen An organism capable of inducing illness.

pesticides A substance or mixture of substances used for the eradicationor control of any pest. This includes behavioural anddevelopmental modifiers, for example plant growth regulators,desiccants or defoliants, but not fertilisers or animal remedies.

pH A measure of whether a substance is acidic or alkaline. In

potable water

aqueous solution a pH of 0 indicates a strong acid. A pH of 14indicates a strong base (alkali), while a pH of 7 is neutral. (Seeunits for a more precise definition.)

Drinking-water which complies with the Drinking—WaterStandards for New Zealand 1995 or later editions oramendments of the Standards.

presumptive coliforms Bacteria whose identification in the early stages ofbacteriological examination highlight the need for furtheridentification of coliform organisms. If absent it is not

45

necessary to proceed with further identification of coliformorganisms.

priority class One of the four classes of determinands defined in theDrinking- Water Standards forNewZealand 1995. The priorityclasses are ranked according to the potential impact of thedeterminand on the quality of the drinking-water and/or thelikelihood that it may be present to the extent that it could causea public health risk.

The Priority 1 protozoa are Giardia and Cryptosporidium

See community drinking-water supply.

The Ministry of Health, the Public Health Commission, anddesignated officers of the Ministry of Health.

The referee methods specified in these Standards will beregarded as the definitive methods.

Alternative methods may be used, but these must provideresults comparable to those obtained by the referee methods.In the event of any dispute about differences in analyticalresults, results obtained using the referee method will bedeemed to be correct.

protozoa

public drinking-water

public health agency

referee method

Register ofComm unityA list of community drinking-water supplies in New ZealandDrinking-WaterSupplies published by the Ministry of Health. It contains details of thein NewZealand water sources, treatment plants, distribution zones and the

identification codes assigned to these. Information on thePriority 2 determinands for each drinking-water supply andon the grading of the supply will also be published in theRegister as available.

renal dialysis A method of treatment of patients who have a kidney disorder.Dialysis involves the diffusion of unwanted body electrolytesout of the patient across a semi-permeable membrane intodialysis water on the other side of the membrane. The dialysiswater must be high quality to avoid the risk of anycontaminants in the dialysis water diffusing back across themembrane and accumulating in the patient.

reticulation The network of pipes, pumps and service reservoirs thatdelivers the drinking-water from the water treatment plant tothe consumers' boundary.

sanitary survey An inspection carried out to check for any direct or potentialcauses of contamination.

secure groundwater Water contained beneath the land surface which is abstractedvia a secure well-head. It must not be under the direct influenceof surface water or demonstrate any significant and rapid shiftscharacteristics such as turbidity, temperature, conductivity orPH which closely correlate to any climatological, surface waterconditions or land use practices. There must also be no insects

46

secure well-head

service reservoir

short-term excursion

SI units

surface water

surrogate

or other macro organisms such as algae, organic debris or largediameter pathogens. Compliance with these requirementsmust have been reliably demonstrated. If any doubt remainsthat the groundwater is secure, check should be made that thewater has been in the aquifer for more than 1 year.

A well-head which incorporates appropriate measures toprevent or minimise the risk of groundwater contamination.Measures include:

• A sealed pumping and piping system including backflowprevention devices

• Seals between the well casing, pipework and surroundingground

• Restrictions on any potentially contaminating land use oractivity in the vicinity of the well-head

A tank forming part of the reticulation in a distribution zonein which drinking-water is stored.

The exceedence of the MAV of a contaminant for a short timewhich does not represent a public health risk.

A system of coherent metric units (Systéme Internationaled'Unités) adopted by the General Conference on Weights andMeasures, the international authority on units.

Water drawn from streams, rivers, lakes, reservoirs, springs.

A determinand used to assess the likely presence orconcentration of another determinand.

surveillance The process of checking that the monitoring of drinking-watersupplies conforms to the specifications set in the Standards.Surveillance is usually conducted by the public health agency.

Tolerable Daily Intake (l'Dl) The intake level in the human which is confidently believed tobe without significant diverse health effects. (Essentially thesame as ADI (Acceptable Daily Intake) except that the lattertends to refer to level which has been formally established bythe World Health Organisation or some other authority.)

thermotolerant coliforms = Bacteria used as indicators that faecal contamination hasfaecal coliforms probably occurred and that the drinking-water needs to be

treated as though there is a probability that pathogens arepresent.

transgression A drinking-water sample is said to transgress the Standardswhen a determinand of any priority class which is present inthe sample exceeds the MAy.

turbidity A measure of loss or clarity in a sample caused by scattering oflight by suspended particles in the sample. For these Standards,turbidity is measured by nephelometry.

47

USEPA

The United States Environmental Protection Authority.

viruses Sub-microscopic particles of nucleic material enclosed in aprotein coat which can replicate themselves inside living cellsand may cause disease.

water supplier or watersupply authority

water treatment process

water treatment plant

well-head

WHO

The organization responsible for some part or all of acommunity drinking-water supply.

A chemical, biological or physical process employed to enhancethe quality of a drinking-water supply prior to distribution.

The point where the drinking-water supply enters thedistribution system, regardless of the treatment process.

The physical structure, facility or device at the land surface fromwhich groundwater is abstracted from subsurface water-bearing formations.

World Health Organisation.

wholesome drinking-water Drinking-water which complies with the Drinking-WaterStandards for New Zealand 1995 or later editions oramendments of the Standards.

48

8 UNITS

1. Basis for Units:

The Drinking- Water Standards for New Zealand l995use the International System of Units(SI), (Système Internationale d' Unites of the Comité International des Poids et Mesures),consistent with the units used in the United States Environmental Protection Authority andthe Australian Drinking-Water Guidelines.

The internationally recognised (Comité International des Poids et Mesures) (CIPM) unit ofvolume is the litre (L).

The SI unit of weight is the kilogram (kg).

The SI unit of length is the metre (m).

The decimal prefixes may be used to form names and symbols of multiples of the SI units.The choice of appropriate multiple is governed by convenience, to result in a numerical valuewithin a practical range.

2. Mass and Concentration

Standard UnitStandardOther UnitsUnitEquivalent UnitsEquivalent UnitsSymbol Symbol

milligrams permg/L or parts perGrams per cubiclitre mgL million, ppmmetre, g/m 3 or gm-3

microgramstg/L or parts per billion,milligrams per cubicper litre&gL'ppb = 10-3 ppmmetre, mg/m 3 or

mgm3

nanogramsng/L or parts per trillionper litrengLppt = 10 ppb

1 mg/L = 1,000 or 103 jxg/L = 1,000,000 or 10 ngIL1 ngJL = 0.001 or 101 [tg/L = 0.000001 or 10 mg/L

Note that one billion is one thousand million or iO

3. Microbiological

Colony forming units per millilitre (c.f.u./mL).

Most probable number per 100 millilitres (MPN/lOOmL).

1 .tm = 0.001 or 10 millimetres

4. Physical & Other

4.1 Aggressiveness These Standards use the Langelier Saturation Index (LSI) to quantifyaggressiveness. The Langelier Saturation Index is defined as the actualPH of the water minus the pH at which the water will be in equilibriumwith solid calcium carbonate, ie

49

4.2 CA

4.3Colour

4.4Conductivity

4.5 pH

4.6 Temperature

4.7Turbidity

LSI = pFI - pH,

WhereLSI = Langelier Saturation Index

PHac = the actual pH

pH, = the pH of the water in equilibrium withcalcium carbonate

The units of the Langelier Saturation Index are therefore pH units,which are dimensionless.

= concentration of the disinfectant in mg/L x exposure time inminutes.

Hazen Colour Unit (HU), sometimes referred to as True Colour Units(TCU).

Strictly speaking, true colour is the colour of a filtered sample. Thecolour of an unfiltered sample is called "apparent colour".

1 HU = 1 mg platinum/L in the form of the chloroplatinate ion.

millisiemens per metre (mS/m or mS.m-1).

1 mS/rn = 10 [tmhos/cm

1 RS/cm = 1 [tmhos/cm

Note that conductivity is strongly influenced by the temperature ofthe sample being tested. Normal practice is to measure theconductivity at 25°C or to convert it to this temperature, includingthe measured temperature in the report.

-log (hydrogen ion activity) = -log a11+

Approximated to indicate -log (hydrogen ion concentration) = -log[H].

Degrees Celsius (°C).

Nephelometric Turbidity Unit (NTU).

The turbidity of a specified concentration of formazin suspension isdefined as 40 NTU.

Alternative standards are defined relative to this standard.

5.

5

5.1

5.2

5.3

50

Chemical

The concentration of some determinands can be expressed using different units.

AsbestosMillion fibres per litre (MFL).

Ammonium ammonium nitrogen x 18/14 = ammonium

NH 4-Nx18/14=NH4

Nitratenitrate nitrogen x 62/14= nitrate

NO 3-Nx 62/14=NO 3

Nitritenitrite nitrogenx 46/14= nitrite

NO2-Nx46/14 x46/14=NO2

5.4 HardnessTotal hardness = calcium hardness + magnesium hardness, expressedas mg/L CaCO3.

Ca as CaCO 3= Ca as Ca x 100/40

Mg as CaCO3 = Mg as Mg x 100/24.3

6.Radioactivity

6.1Activity of Radionuclide

Becquerel per litre (Bq/L) or picocurie per litre (pCi/L).

1 picocurie = 3.7 x 10 Becquerel

second to the power minus one, s.

1 curie (Ci) = 3.7 x 10° Bq.

millisievert (mSv).

/

51

9 INDEX OF SYNONYMS(for chemicals of health significance)

This index of synonyms can be used to determine which name for a compound has been usedin these Standards, when there is more than one possibility. For example for "bendioxide,see bentazone", "bendioxide" is the name looked up, and "bentazone" is the name by whichbendioxide is referred to in the Standards.acetonyl chloride, see chloroa cetoneacrylamidealachioraldicarbaidrinantimonyarsenicasbestosatrazinebariumbasudin, see diazmonbendioxide, see bentazonebentazonebenzo[a]pyrenebenzeneberylliumN,N-bis(carboxymethyl)glycine, see nitrilotriacetic acidbis(2-ethylhexyl)adipate, see di(2-ethy1hexy1)adipatebis(2-ethylhexyl)phthalate, see di(2-ethy1hexy1)phtha1ateboronbromatebromochioroacetonitrilebromochloroethanen itrile, see bromochioroacetonitrilebromodichloromethanebromoformcadmiumcarbofurancarbon tetrachloridechloracetone, see chioroacetonechloral hydrate, see trichioroacetaldehydechloramineschloratechlordane

52

chlorinechloritechloroacetic acid, see monochioroacetic addchloroacetone

chlorobenzene, see in on ochioro benzenechiorodibromomethane, see dibromochioromethane3-chloro-1,2-dibromopropane, see 1,2-dibromo.-3-chloropropane3-chloro-4-(dichloromethyl)-5-hydroxy-2(h)-furanone, seeMK2-chloro-2 1 ,6 1 -dimethyl-N-methoxymethyl acetanilide, see aiachior6-chloro-N,N'-dimethyl-1,3,5-triazine-2,4-diamine, see simazine1-chloro-2,3-epoxypropane, see epichiorohydrinchioroethanoic acid, see rnonochioroaceticacidchioroethene, see vinyl chloridechiorethene, see 1,1,1-trichioroethanechioroethylene, see vinyl chloride6-chloro-N-ethyl-N'-(l-methylethyl)-1, 3,5-triazine-2,4-diamine, see atrazine2-chloro-6 1-ethyl-N-(2-methoxy-1-methylethyl)acet-o-toluidide, see rnetolachlorchloroform -chioromethanenitrile, see cyanogen chloridechioromethyl ethylene oxide, see epichiorohydrinchioromethyl oxirane, see epichiorohydrin4-chloro-2-methylphenoxyethanoic acid, see MCPA2-chlorophenol6-chloro-3-phenylpyridazin-4-yl-S-octyl thiocarbonate, see pyridatechioropicrin1-chloro-2-propanone, see chloroacetone4-chloro-o-toloxyacetic acid, see MCPA3-(3-chloro-p-tolyl)-1,1-dimethyl urea, see chlortoluron4-(4-chloro-o-tolyoxy)butanoic acid, see MCPB2-(4-chloro-o-tolyoxy)propionic acid, see mecopropchlorotoluronchiorpyriphoschiortoluron, see chlorotoluronchromiumcombined chlorine, see chioraminescoppercyanidecyanogen chloridediazinon2,4-D

53

2,4-DBDBCP,see 1,2-dibromo-3-chloropropane1,1-DCA,see 1,1- dichloroethane1,2-DCA,see 1.2- dichloroethaneDCA,see dichioroacetic acid1,2-DCB,see 1,2-dichiorobenzene1, 3-DCB,see 1,3-dichlorobenzene1,4-DCB,see 1,4-dichlorobenzene1, 1-DCE,see il-dichioroethene1,2-DCE,see 1,2-dichioroetheneDCP,see 1,3-dichioropropeneDCPA,see propanhlDDTDEHA, see &(2-ethylhexyl)adipateDEHP, see di(2-ethylbexyl)phthalatedi(2-ethylhexyl)adipatedi(2-ethylhexyl)phthalatedialkyltins1,2-dibromo-3-chloropropanedibromoacetonitriledibromochioromethanedibromoethanenitrile, see dibromoacetonitrile1, 2-dibromoethane, see ethylene dibromidedichioramine, see chioraminesdichloro-1, 3-propene, see 1,3-dich1oropropenedichioroacetic aciddichioroacetonitrile1,4-dichlorobenzene1,2-dichlorobenzene1,3-dichlorobenzenedichiorobromomethane, see bromodichioromethane1,1 dichloroethane1,2 dichioroethanedichioroethanenitrile, see dichioroacetonitriledichioroethanoic acid, see dichioroacetic acid1,1-dichioroethene1,2-dichioroethenedichioromethane2,4-dichiorophenoldichiorophenoxyacetic acid, see 2,4-D

54

4-(2,4-dichlorophenoxy)butanoic acid, see 2,4-DBdichiorophenoxybutyric acid, see 2,4-DB2,4-dichlorophenoxyethanoic acid, see 2,4-D2-(2,4-dichlorophenoxy)propionic acid, see dichlorpropN-(3,4-dichlorophenyl)propionamide, see propanil1,2-dichioropropane1,3-dichioropropane1,3-dichioropropenedichiorpropdieldrin, see aJdri/dieldrin2,3-dihydro-2,2-dimethyl-7-benzofuranol methylcarbamate, see carbofuxan1,2-dimethylbenzene, seexylenes1,4-dimethylbenzene, see xylenes1,3-dimethylbenzene, see xylenes2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine, see trifluralinDMDT, see methoxychior2,4-DP, see dichlorpropdursban, see chioropyriphosEDB, see ethylene dibromideedetic acid, see EDTAEDTAepichiorohydrinethylbenzeneethylenediamine tetraacetic acid, see ED TAethylene dibromideethylene dichloride, see 1,1 dichloroethane or 1,2 dichloroethaneS-ethyl-N,N-hexamethylenethiocarbamate, see molinateN-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine, see pen diin ethalin.fenopropfluorideformaldehydegamma benzene hexachioride, see lindanegamma-BHC, see lindanegamma-HCH, see lindanegesapon, see diazinonHCB, see hexachlorobutadieneHCB, see hexachlorobenzeneHEOD, see dieldrinheptachlorheptachlor epoxide, see heptachlor/heptachlor epoxide

55.

1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene, see heptachlorhexachlorobenzenehexachiorobutadienehexachiorocyclohexane, seelindane1,2,3,4, 10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydroendo,exo-1,4:5,8-dimethanonaphthalene, see dieldrin1,23,4,10, 10-hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5,8-dimethanonaphthalene, see aldrin3-(4-isopropylphenyl)-1,1-dimethyl urea, see isoproturonisoproturonleadlindanelorsban, see chiorpyriphosmanganese

MCB, see tnonochlorobenzeneMCP, see MCPAMCPAMCPBMCPP, see rnecopropmecopropmercurymetadichlorobenzene, see 43-dichlorobenzenemetadimethylbenzene, see xylenesmethanal, see formaldehydemethoxychiormethylbenzene, see toluenemethyichioroform, see 1,1,1-trichloroethanemethylene chloride, see dichioromethane3-(1-methylethyl)-1H-2, 1,3-benzothiadiazin-4(3H)-one-2,2-dioxide, see bentazone2-methyl-2-(methylthio)propionaldehyde-0-methylcarbamoyloxime, see aldicarbmetolachiormolinatemolybdenummonochioramine, see chiorarninesmonochloroacetic acidmonochloroacetone, see chioroacetonemonochlorobenzeneMXN-(3,5-dichlorophenyl)-1,2-dimethylcyclopropane-1,2-dicarboximide, see pro cymidonenickelnitrate & nitrite

56

nitrilotriacetic acid.nitrochioroform, see chioropicrinNTA, see nitrilotriacetic acid1,2,4,5,6,7,8, 8-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-methano-1H-indene, see chiordane0,0-diethyl 0-2-isopropyl-6-methylpyrimidin-4-yl phosphothioate see diazinon0,0-diethyl 0-3, 5,6-trichloro-2-pyridyl phosphorothioate, see chiorpyriphosorthochiorophenol, see 2-chiorophenolorthodichlorobenzene, see 1,2-dichlorobenzeneorthodimethylbenzene, see xylenesPAH, see polynudear aromatic hydrocarbonsparadichlorobenzene, see 14-dichlorobenzeneparadimethylbenzene, seexylenesPCE, see tetrachioroethenePCP, see pentachiorophenolpendimethalinpentachiorophenolperchlorobenzene, see hexachlorobenzenepermethrin3-phenoxybenzyl (1RS)- cis, trans-3-(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanecarboxylate, see perrn ethrinphenyl chloride, see monochlorobenzenephenyl hydride, see benzenephenylethene, see styrenepirimiphos methylpolynuclear aromatic hydrocarbonsprocymidonepropanilpropenamide, see acrylarnidepyridateseleniumsilversilvex, see fenopropsimazinesodium monofluoroacetate, see 1080sodium fluoroethanoate, see 1080sodium fluoroacetate, see 1080styrenesumisclex, see pro cymidone2,4,5-1TBTO, see tributyltin oxide

57

1, 1,1-TCA, see 1,1,1- trichloroetha.neTCA, see trichioroacetic acid1,2,3-TCB, seetrichlorobenzenes1,2,4-TCB, see trichlorobenzenes1,3,5-TCB, see trichloroben.zenesTCE, see trichioroethene2,4,5-TCPPA, see fenopropterbuthylazinetetra chioroethenetetrachioroethylene, see tetrachioroethenetetrachioromethane, see carbon tetrachloridethalliumTHM, see bromodichioromethane or dibromochioromethane or tribromomethane ortrichioromethanetintoluene2,4,5-TP, see fenoproptribromomethane, see bromoformtributyltin oxidetrichioramine, see chioraminestrichioroacetaldehydetrichioroacetic acidtrichloroacetonitriletrichlorobenzenes1,2,3-trichlorobenzene, see trichlorobenzenes1,2,4-trichlorobenzene, see trichiorobenzenes1,3,5-trichlorobenzene, see trichlorobenzenes1,1, 1-trichloro-2,2-bis(4-chlorophenyl)ethane, see DDT1,1, 1-trichloro-2,2-bis(4-methoxyphenyl)ethane, see methoxychiortrichioroethanal, see trichioroacetaldehyde1, 1,1-trichloroethanetrichioroethanenitrile, see trichioroacetonitriletrichioroethanoic acid, see trichloroacetic acidtrichioroethenetrichioroethylene, see trichioroethenetrichloromethane, see chloroformtrichioronitromethane, see chioropicrin2,4,6-trichiorophenol2-(2,4,5-trichlorophenoxy)propionic acid, see silvextrichlorophenoxyacetic acid, see 2,4,5-T

58

2,4,5-trichlorophenoxyethanoic acid, see2,45-T3,5,6-trichloro-2-pyridyloxyacetic acid, see triclopyr3 1 5,6-trichloro-2-pyridyloxyethanoic acid, see triclopyrtriclopyrtrifluralintrigylcine, see nitrilotriaceticacidtrihalomethane, see bromodicbloromethane ordibromochioromethane or tribromomethaneor trichloromethaneuraniumVC, see vinyl chloridevinyl chloridevinyl benzene, see styrenevinylidene chloride, see 1,1-dichioroethenexylenes666, see lindane1080

5

10 TABLES OF SYNONYMS

(for organic determinands of health significance and pesticides)

Use of the table of synonyms

This table lists the organic determinands of health significance and the pesticides in thealphabetical order in which they appear in the Table of MAVs in Section 13. The name usedin these standards may appear in the column for JUPAC Nomenclature, Common Name orAbbreviation and are given in bold. Where available, other synonyms are given in theappropriate columns.

TABLE 10.1 SYNONYMS FOR ORGANIC DETERMINANDS OF HEALTH SIGNIFICANCE.JUPAC NomenclatureCommon NamesAbbrevi- CAS

ationRegistryNumber

propenamide acrylamide 79-06-1benzene phenyl hydride 71-43-2benzo[a]pyrene 50-32-8bromochloroethanenitrilebromochioroacetonitrile 83463-62-1bromodichioromethanedichlorobromomethane 75-27-4tribromomethane bromoform 75-25-2tetrachloromethanecarbon tetrachloride 56-23-5monochloramine chioramines, or combineddichioramine chlorinetrichioramine1-chloro-2-propanonechioroacetone, or 78-95-5

chioracetone or acetonylchloride, ormonochloroacetone

trichloromethane chloroform 67-66-32-chiorophenol orthochlorophenol 95-57-8trichioronitromethanechioropicrin, or 76-06-2

nitrochloroformdiaikyltinsdibromoethanenitriledibromoacetonitrile 3252-43-5dibromochioromethanechlorodibromomethane 124-48-1dichioroethanoic aciddichloroacetic acidDCA79-43-6dichloroethanenitriledichloroacetonitrile 3018-12-01,2-dichlorobenzeneorthodichlorobenzene1,2-DCB95-50-11,3-dichlorobenzenemetadichlorobenzene1, 3-DCB541-73-11,4-dichlorobenzeneparadichlorobenzene1,4-DCB106-46-71,1-dichioroethaneethylene dichloride1,1-DCA75-34-31,2-dichioroethaneethylene dichloride1,2-DCA107-06-21,1-dichioroethenevinylidene chloride1,1-DCE75-35-4

60

TABLE 10.1 SYNONYMS FOR ORGANIC DETERMINANDS OF HEALTHSIGNIFICANCE (cont.)

IUPAC NomenclatureCommon Names Abbrevi- CASationRegistry

Number1,2-dichioroethene ethylene dichloride1,2-DCE540-59-0dichioromethane methylene chloride 75-09-22,4-dichlorophenol 120-83-2di(2-ethylhexyl)adipatebis(2-ethylhexyl)adipateDEHA103-23-1di(2-.ethylhexyl)phthalatebis(2-ethylhexyl) phthalate DEHP117-81-7ethylenediamine tetra-edetic acid EDTA60-00-4acetic acid1-chloro-2,3-epoxypropaneepichiorohydrin, or 106-89-8

chioromethyl oxirane, orchioro methyl ethyleneoxide

ethylbenzene 100-41-4methanal formaldehyde 50-00-0hexachiorobutadiene HCB87-68-3chioroethanoic acid monochioroacetic acid, 79-11-8

or chioroacetic acidchlorobenzene monochlorobenzene, orMCB(50717-45-8)

phenyl chloride replaced by108-90-7

3-chloro-4-(dichloromethyl)- MX77469-76-05-hydroxy-2(5h)-furanoneN,N- nitrilotriacetic acid, orNTA139-13-9bis(carboxymethyl)glycinetriglycine 556-33-2

polynuclear aromaticPAHhydrocarbons

phenylethene, or styrenestyrene, or 100-42-5vinyl benzene

tetrachioroethene tetrachioroethylenePCE127-18-4methylbenzene, or toluenetoluene 108-88-3tributyltin oxide TBTO56-35-9trichioroethanal trichioroacetaldehyde, or 75-87-6

chloral hydratetrichioroethanoic acidtrichioroacetic acidTCA76-03-9trichioroethanenitriletrichioroacetonitrile 545-06-21,2, 3-trichlorobenzenetrichlorobenzenes1,2, 3-TCB 87-61-61,2,4-trichlorobenzene 1,2,4-TCB120-82-11,3,5-trichlorobenzene 1,3,5-TCB108-70-31,1,1-trichioroethanemethylchloroform, or1,1,1-TCA 71-55-6

chiorothenetrichioroethene trichioroethyleneICE79-01-62,4,6-trichiorophenol TCP88-06-2

61

TABLE 10.1 SYNONYMS FOR ORGANIC DETERMINANDS OF HEALTHSIGNIFICANCE (cont.)


Numbertrihalomethane THM

chioroethene vinyl chloride, or VC75-01-4chioroethylene

1,2-dimethylhenzenexylenes, or 95-47-61,3-dimethylbenzeneorthodimethylbenzene, or 108-38-31,4-dimethylbenzenemetadimethylbenzene, or 106-42-3

paradimethylbenzene

62

TABLE 10.2 SYNONYMS FOR PESTICIDES


Number2-chloro-2 1 ,6 1 -dimethyl-N- alachlor 15972-60-8methoxymethyl acetanilide2-methyl-2-(methylthio)aldicarb 116-06-3pro pionaldehyde-O-methylcarbamoyloxime1,2,3,4,10,10-hexachioro-aidrin 309-00-21,4,4a,5;8,8a-hexahydro-1,4:5,8-dimethanonaph-thalene6-chloro-N-ethylN'-(I-atrazine 1912-24-9methylethyl)-1,3,5-triazine-2,4-diamine3-(1-methylethyl)-1H-2,1,3- bentazone, or 25057-89-0benzothiadiazin-4(3H)-one bendioxide2,2-dioxide2,3-dihydro-2,2-dimethyl-7- carbofuran 1563-66-2benzofuranol methylcar-bamate1,2,4,5,6,7,8,8-octachioro- chlordane 57-74-92,3,3a,4,7,7a-hexahydro-4,7-methano-1H-indene3-(3-chloro-p-tolyl)-1,1-chiorotoluron, or 15545-48-9dimethyl urea chiortoluron0,0-diethyl 0-3,5,6-tn-chlorpyriphos, 2921-88-2chloro-2-pyridyllorsban, dursbanphosphorothioate2,4-dichiorophenoxydichiorophenoxyacetic acid2,4-D94-75-7ethanoic acid4-(2,4-dichlorophenoxy)dichiorophenoxybutyric acid2,4-DB94-82-6butanoic acid1,1,1-trichloro-2,2-bis(4- DDT50-29-3chlorophenyl)ethane0,0-diethyl 0-2-isopropyl- diazinon 333-41-56-methylpyrimidin-4-ylgesapon, basudinphosphothioate1,2-dibromo-3- 3-chloro-1,2- DBCP96-12-8chioropropane dibromopropane1,2-dichioropropane 78-87-51,3-dichioropropane1,3-dichioropropenedichl6ro-1,3-propeneDCP542-75-62-(2,4-dichlorophenoxy)dichiorprop 2,4-DP120-36-5propionic acid

63

TABLE 10.2 SYNONYMS FOR PESTICIDES (cont.)

IUPAC NomenclatureCommon Names Abbreviation CASRegistryNumber

1,2,3,4,10, 10-hexachloro-6, dieldrin HEOD60-57-17-epoxy-1,4,4a,5,6,7,8,8a-octahydroendo,exo-1,4:5,8-dimethanonaphthalene1,2-dibromoethaneethylene dibromideEDB106-93-42-(2,4,5-trichl6rophenoxy) fenoprop, or silvex2,4,57CPPA, 93-72-1propionic acid 2,4,5-TP1,4,5,6,7,8,8-heptachioro- heptachlor 76-44-83a,4,7,7a-tetrahydro-4,7-methanoindene

heptachlor epoxide 1024-57-3hexachlorobenzenehexachlorobenzene, orHCB118-74-1

•perchlorobenzene3-(4-isopropylphenyl)-1, 1- isoproturon 34123-59-6dimethyl ureahexachiorocyclohexanelindane, or gamma-BHC, 58-89-9

gamma benzene 666, gamma-hexachioride HCH

4-chloro-2- 4-chloro-o-toloxyacetic acid MCPA, MCP94-74-6methylphenoxyethanoicacid4-(4-chloro-o- MCPB94-81-5tolyloxy)butanoic acid2-(4-chloro-o- mecoprop MCPP7085-19-0tolyloxy)propionic acid1,1, 1-trichloro-2,2-bis(4-methoxychior DMDT72-43-5methoxyphenyl)ethane2-chloro-6'-ethyl-N-(2-metolachlor 51218-45-2methoxy-1-methylethyl)acet-o-toluidideS-ethyl-N,N- molinate 2212-67-1hexamethylenethio-carbamateN-(1-ethylpropyl)-2,6-pendimethalin 40487-42-1dinitro-3,4-xylidinepentachlorophenolpentachiorophenolPCP87-86-53-phenoxybenzyl (iRS)-permethrin 52645-53-1cis,trans-3-(2,2-dichloro-vinyl)-2,2-dimethyl cyclo-propane carboxylate0-2-diethylamino-6-pirimiphos-methyl 29232-93-7methylpyrimidin-4-yl 0,0-dimethylphosphorothioate

64

TABLE 10.2 SYNONYMS FOR PESTICIDES (cont.)

IUPAC NomenclatureCommon Names1Abbreviation CASRegistryNumber

N-(3,5-dichlorophenyl)-1,2- procymidone 32809-16-8dimethylcyclopropane-1,2- sumisciexdicarboximideN-(3,4-dichlorophenyl)propanil 709-98-8propionamide -6-chloro-3-phenylpyrida- pyridate 55512-33-9zin-4y1 S-octyl thiocarbonate -6-chloro-N,N'-dirnethyl-simazine - 122-34-91,3,5-triazine-2,4-diamine

- 2tert-butylaminb-4-chl6r6- terbuthy1ainë .5915-41-3 -6-ethylamino-1,3,5-triazine2,4,5- trichiorophenoxyacetic2,4,5-T93-76-5trichlorophenoxyethanoic acidacid3,5,6-trichloro-2-trichlo.pyr, or 55335-06-3.:pyridyloxyethanoic acid3,5,6-trichloro-2-

pyridyloxyacetic acid2,6-dinitro-N,N-dipr6pyl- trifiuralin 1582-09-84-(trifluoromethyl) -benzenaminesodium fluoroethanoatesodium fluoroacetate, or108062-74-8

sodium monofluoroacetate

65

11 SAMPLING AND ANALYTICAL REQUIREMENTS FORCHEMICAL DETERMINANDS OF HEALTH SIGNIFICANCE

The preservation and storage requirements for each method are those given in the specified method.

TABLE 11.1 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR INORGANICDETERMINANDS OF HEALTH SIGNIFICANCE.

NAME SAMPLING ContainerReferee Method Some Alternative MethodsLOCATIONTW DZ

Antimony /P(A), G(A) - GFAA (APHA 3113) (pre-concentration may - ICP-MS (EPA 200.8)be necessary)

Arsenic /V P(A), G(A) - GFAA (APHA 3113) - HGAA (APHA 3114)- ICP-MS (EPA 200.8)

Barium // P(A), G(A) - GFAA (APHA 3113) - FAA (APHA 3111)- ICP (APHA 3120)

Boron V/P- Colorimetric method (Boron in Waters,- Colorimetric method (APHA 4500-B B)Effluents, Sewage and Some Solids, 1980Azomethine-H_ Parts _C,D_ HMSO _[1981])

Bromate /P- IC (ref. JAW WA (1992), 84(11), 88)Cadmium V P(A), G(A) - GFAA (APHA 3113) - ICP (APHA 3120)

- ICP-MS (EPA 200.8)Chioramines /G- TITR (APHA 4500Cl F) - TITR (APHA 4500C1 D)Chlorine VG- TITR (APHA 4500C1 F) - TITR (APHA 4500C1 D)Chlorite /P- IC (ref. JAW WA (1992), 84(11), 88)Chromium V P(A), G(A) - GFAA (APHA 3113) - FAA (APHA 3111)

- ICP (APHA 3120)- ICP-MS (EPA 200.8)

TABLE 11.1 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR INORGANICDETERMINANDS OF HEALTH SIGNIFICANCE (cont.)

NAME SAMPLING ContainerReferee Method Some Alternative MethodsLOCATIONTW DZ-

Copper / P(A), G(A) - GFAA (APHA 3113) - FAA (APHA 3111)- ICP (APHA 3120)- ICP-MS (EPA 200.8)

Cyanide (total)//P - Total cyanide after distillation(APHA 4500-CN C)

Cyanogen chloride/G(S)- (APHA 4500-CN J)Fluoride //P - Ion selective electrode (API-IA 4500-F C)- IC (APHA 4110)

- Colorimetric method, SPADNS(APHA 4500-F D)

Lead /P(A), G(A) - GFAA (APHA 3113) - ICP (APHA 3120)- ICP-MS (EPA 200.8)

Manganese / P(A), G(A) - GFAA (APHA 3113) - FAA (APHA 3111)- ICP (APHA 3120)- ICP-MS (EPA 200.8)

Mercury // G(A)- CVGAA (3112 B)Molybdenum// P(A), G(A) - GFAA (APHA 3113) - ICP (APHA 3120)

- ICP-MS (EPA 200.8)Nickel /P(A), G(A) - GFAA (APHA 3113) - ICP (APHA 3120)

- ICP-MS (EPA 200.8)Nitrate / P. G- Cadmium reduction (APHA 4500-NO 3-E)- IC (APHA 4110)

- Ion selective electrode (APHA 4500-NO3-D)

Nitrite /P, G- Colorimetric Method (APHA 4500-NO 2-B)- IC (APHA 4110)Selenium // P(A), G(A) - GFAA (APHA 3113) - HGAA (APHA 3114)

- ICP (API-IA 3120)- ICP-MS (EPA 200.8)

00

TABLE 11.2 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR ORGANIC


Acrylamide // - HPLC/UVD (Determination of acrylamidmonomer in waters and polymers 1987.HMSO, 1988)

Benzene // G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D,EPA502.2)

Benzo[ alpyrene /G(S)- LSE/GC-MS (EPA 525) - LLE/HPLC (EPA 550)-LSE/HPLC (EPA 550.1)

Bromodichloromethane/G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D,EPA 502.2)

- LLE/GC-ECD (EPA 551)Bromoform / G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D,

EPA 502.2)- LLE/GC-ECD (EPA 551)

Carbon tetrachloride /G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D,EPA 502.2)

- LLE/GC-ECD (EPA 551)Chloroform / G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D,

EPA 502.2)- LLE/GC-ECD (EPA 551)

Di(2-ethylhexyl)adipate/G(S)- LSE/GC-MS (EPA 525) - LLE or LSE/GC-PID (EPA 506)Di(2-ethylhexyl)phthalate/G(S)- LSE/GC-MS (EPA 525) - LLE or LSE/GC-PID (EPA 506)Dibromoacetonitrile /G(S)- LLE/GC-ECD (EPA 551)Dibromochioromethane/ G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC (APHA 6230D, EPA 502.2)

- LLE/GC-ECD (EPA 551)Dichloroacetic acid /G(S)- LSE/GC-ECD (EPA 552.1) - LLE/GC-ECD (APHA 6233B)

TABLE 11.2 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR ORGANICDETERMINANDS OF HEALTH SIGNIFICANCE (cont.)


Dichioroacetonitrile /G(S)- LLE/GC-ECD (EPA 551)1,2-Dichlorobenzene /G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)

- LLE/GC-MS (APHA 6410B)1,4-Dichlorobenzene.f/G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)

- LLE/GC-MS (APHA 6410B)1,2-Dichloroethane /G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)1,1-Dichioroethene,(/G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)1,2-Dichloroethene//G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)Dichioromethane /G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)EDTA // - Reverse phase ion pair liquid

chromatography (Bergers & de Groo,1994, Wat. Res. 28,_(3),_639)

Epichlorohydrin //G(S)- GC/ECD (Pesselman and Feit, 1988,J.Chrom., 439,_448-452)

Ethylbenzene /V G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)Formaldehyde / - LSE/HPLC (EPA 554)HexachiorobutadieneVV G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)MonochlorobenzeneV/ G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)Nitrilotriacetic acidV/ - GC-NSD (Malaiyandi et al, 1979, Env.

Sci. & Tech., j. 59-61; Aue et al, 1972,J. of Chrom.,_72,_259-267)

Styrene // G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)Tetrachioroethene /G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)

- LLE/GC-ECD (EPA 551)Toluene / G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)

to

0

TABLE 11.2 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR ORGANICDETERMINANDS OF HEALTH SIGNIFICANCE (cont.)

NAME SAMPLING ContainerReferee Method Some Alternative MethodsLOCATION1W DZ

Tributylin oxide I'/ - LLE/GC-FPD (Greaves and Unger, 1988,Biomed. & Env. Mass _Spec. _15,_565-5 69)

Trichloroacetaldehyde/ / - LLE/GC-ECD (EPA 551)chloral hydrateTrichioroacetic acid /G(S)- LSE/GC-ECD (EPA 552.1) - LLE/GC-ECD (APHA 6233B)Trichloroacetonitrile /G(S)- LLE/GC-ECD (EPA 551)Trichlorobenzenes//G(S)- P&T/GC-MS (APHA 62101), EPA 524.2) - P&T/GC-Hall&PID (API-IA 6230D, EPA 502.2)1,1,1-Trichloroethane//G(S)- P&T/GC-MS (APHA 6210D, EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)

- LLE/GC-ECD (EPA 551)Trichioroethene /G(S)- P&T/GC-MS (APHA 62101), EPA 524.2) - P&T/GC-Hall&PID (APHA 62301), EPA 502.2)

- LLE/GC-ECD (EPA 551)2,4,6-Trichlorophenol /G(S)- LLE/GC-ECD (APHA 6233B) - LLE/GC-ECD&FID (APHA 6420)

- LLE/G C-MS (APHA 6410B)- Acetylation/LLE/G C-MS (EPA 1653)

Vinyl chloride /G(S)- P&T/GC-MS (APHA 62101), EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)Xylenes /G(S)- P&T/GC-MSD (APHA 62101), EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D, EPA 502.2)

TABLE 11.3 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR PESTICIDES.


Alachior /vi G - LSE/GC-MS (EPA 525) - LLE/GC-NPD (EPA 507)- LLE/GC-ECD (EPA 505)

Aldicarb vivi G - RP HPLC (EPA 531.1)Aldrin/Dieldrin vivi G - LLE/GC-ECD (APHA 6630C) - LLE/GC-ECD (EPA 505)Atrazine vivi G - LSE/GC-MS (EPA 525) - LLE/GC-NPD (EPA 507)Bentazone Vvi G - LSE/GC-ECD (EPA 515.2) - LLE/GC-ECD (APHA 6640B)

- HPLC/UVD (EPA 555)Carbofuran vivi G - RP HPLC (EPA 531.1)Chlordane vivi G - LLE/GC-ECD (APHA 6630C) - LLE/GC-ECD (EPA 508)Chiorotoluron vi vi GChiorpyriphos vivi G - LLE/GC-NPD or FPD (Organo-phosphorus

pesticides in river and drinking water, tentativemethod 1980; and Organo-phosphorus pesticidesin sewage sludge: organo-phosphorus pesticidesin river and drinking water: an addition, 1985.HMSO, 1986)

2,4-D vivi G - LSE/GC-ECD (EPA 515.2) - LLE/GC-ECD (APHA 6640B)- HPLC/UVD (EPA 555)

2,4-DB vi/ G - LSE/GC-ECD (EPA 515.2) - LLE/GC-ECD (APHA 6640B)- HPLC/UVD (EPA 555)

DDT + isomers vi / G - LLE/GC-MS (APHA 6410B) - LLE/GC-ECD (APHA 6630B)- LLE-GC-ECD (EPA 508)

t'-

TABLE 11.3 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR PESTICIDES (cont.)


Diazinon G - LLE/GC-NPD (EPA 507) - LLE/GC-NPD or FPD (Organo-phosphoruspesticides in river and drinking water, tentativemethod 1980; and Organo-phosphorus pesticidesin sewage sludge: organo-phosphorus pesticidesin river and drinking water: an addition, 1985.HMSO, 1986)

1,2-Dibromo-3- // G - P&T/GC-MS (APHA 62101), EPA 524.2) - P&T/GC-Hall&PID (APHA 6230D)chloropropane - LLE/GC-ECD (APHA 6231B)

- LLE/GC-ECD (EPA 551)1,2-Dichloropropane//G - P&T/GC-MS (APHA 62101), EPA 524.2) - P&T/GC-Hall&PID (EPA 502.2, APHA 6230D)1,3-Dichloroproperie//G - P&T/GC-MS (APHA 62101), EPA 524.2) - P&T/GC-HALL&PID (APHA 62301), EPA

502.2)Dichlorprop // G - LSE/GC-ECD (EPA 515.2) - LLE/GC-ECD (APHA 6640B)

- HPLC/UVD (EPA 555)Fenoprop /I' G - LSE/GC-ECD (EPA 515.2) - LLE/GC-ECD (APHA 6640B)Heptachlor and heptachlor //G - LLE/GC-ECD (EPA 505) - LLE/GC-ECD (EPA 508)epoxideHexachlorobenzene// G - LSE/GC-MS (EPA 525) - LLE/GC-ECD (EPA 508)

- LLE/GC-ECD (EPA 505)Isoproturon // GLindane // G - LSE/GC-MS (EPA 525) - LLE/GC-ECD (EPA 508)

- LLE/GC-ECD (EPA 505)- LLE/GC (APHA 6630B)

MCPA / / G - HPLC/UVD (EPA 555) - LLE/GC-ECD (AHPA 6640B)Mecoprop / / G - LLE/GC-ECD (AHPA 6640B)

TABLE 11.3 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR PESTICIDES (cont.)NAME SAMPLING ContainerReferee Method Some Alternative Methods

LOCATIONTW DZ

Methoxychior // G - LSE/GCMS (EPA 525) - LLE/GC (APHA 6630B)- LLE/GC-ECD (EPA 508)- LLE/GC-ECD (EPA 505)

Metolachior // G - LLE/GC-NPD (EPA 507)Molinate /,/ G - LLE/GC-NPD (EPA 507)Pendimethalin // GPentachiorophenol//G - LSE/GC-MS (EPA 525) - LSE/GC-ECD (EPA 515.2)

- Acetylation/LLE/GC-MS (EPA 1653)Permethrin // G - LLE/GC-ECD (EPA 508)Pirimiphos methyl//G - LLE/GC-NPD or FPD (Organo-phosphorus

pesticides in river and drinking water,tentative method 1980; and Organo-phosphorus pesticides in sewage sludge:organo-phosphorus pesticides in river anddrinking water: an addition, 1985. HMSO,1986)

Procymidone / / GPropanil // GPyridate // GSimazine // G - LSE/GC-MS (EPA 525) - LLE/GC-NPD (EPA 507)2,4,5-T G - LSE/GC-ECD (EPA 515.2) - LLE/GC-ECD (APHA 6640B)

- HPLC/UVD (EPA 555)Terbuthylazine //G - LLE/GC-NPD (Chiorophenoxy acidic

herbicides, trichlorobenzoic acid, chiorophenols,triazines and glyphosate in water 1985. HMSO,1986)

Triclopyr // G - LLE/GC-ECD (APHA 6640B)

Kt-

TABLE 11.3 SAMPLING REQUIREMENTS, REFEREE METHOD AND SOME ALTERNATIVE ANALYTICAL METHODS FOR PESTICIDES (cont.)


Trifluralin // G - LLE/GC-ECD (EPA 508)1080 // G - LSE/GC-ECD Ozawu & Tsukioka, 1987,

Anal. Chem.,59, 2914-2917

Note: In the analysis of the organic determinands it is the extraction method which is important. The choice of the final method of detection eg MSD,ECD etc. affects the sensitivity and selectivity of the analysis.

ABBREVIATIONS:Container: G - glass, P - plastic, (A) - acid washed, (S) - solvent washedDZdistribution zoneTWwater leaving the treatment plant

Analytical Methods:CVGAA - cold vapour atomic absorption methodECD -electron capture detectorFAA -flame atomic absorptionFID -flame ionization detectorFPD -flame photometric detectorGC -gas chromatographyGFAA -graphite furnace atomic absorptionHGAA -hydride generation atomic absorption.HPLC -high pressure liquid chromatographyIC -ion chromatographyICP-inductively coupled plasma spectrometryLLE -liquid/liquid extraction

LSE-MS.P&T -ND-NPD-PID-RPHPLC -Titr-UVD-

liquid/solid extractionmass spectrometerpurge and trapnitrogen specific detectornitrogen/phosphorus detectorphotoionization detectorreversed-phase HPLCtitrimetric methodultraviolet detection

• References:APHA - Standard methods for the examination of water and wastewater. - Washington, D.C. : American Public Health Association, 1992.EPA - U.S. Environmental Protection AgencyHMSO - Methods for the examination of waters and associated materials. - London.

c-TI

12 C.t VALUES FOR DISINFECTANTSTable 12.1

C.t values for 99.9% inactivation of Giardia lam blia by free chlorine at 0.5°Cor lower and turbidity below 1 NTU.

Free available pHChlorine (mg/L).min

less greaterthan than6.06.57.07.58.08.59.5

<0.4 1371631952372773293900.6 1411682002392863424070.8 1451722052462953544221.0 148176210253,3043654371.2 1521802152593133764511.4 1551842212663213874641.6 1571892262733293974771.8 1621932312793384074892.0 1651972362863464175002.2 16920112422973534265112.4 1722052472983614355222.6 1752092523043684445332.8 1782132573103754525433.0 181217261316382460552

Table 12.2

CA values for 99.9% inactivation of Giardia lam blia by free chlorine at 5.0°Cand turbidity below 1 NTU.

Free available pHChlorine (mgfL).min


<0.4 971171391661982362790.6 1001201431712042442910.8 1031221461752102523011.0 1051251491792162603121.2 1071271521832212673201.4 1091301551872272743291.6 1111321581922322813371.8 1141351621962382873452.0 1161331652002432943532.2 1181401692042483003612.4 120143 1 1722092533063682.6 1221461752132583123752.8 1241481782172633183823.0 126151182221 1 268324389

76

Table 12.3

C.tvalues for 99.9% inactivation of Giardia lamblia by free chlorine at 10.0°Cand turbidity below 1 NTU.



<0.4 73881041251491772090.6 75901071281531832180.8 78921101311581892261.0 79941121341621952341.2 80951141371662002401.4 82981161401702062471.6 83991191441742112531.8 861011221471792152592.0 871041241501822212652.2 891051271531862252712.4 901071291571902302762.6 921101311601942342812.8 931111341631972392873.0 95113137166201243292

Table 12.4

C.t values for 99.9% inactivation of Giardia lain blia by free chlorine at 15.0°Cand turbidity below 1 NTU.

Free available pHChlorine (mgfL).min


<0.4 49597083991181400.6 506072861021221460.8 526173881051261511.0 536375901081301561.2 546476921111341601.4 556578941141371651.6 5666 1 79961161411691.8 576881981191441732.0 5869831001221471772.2 5970851021241501812.4 6072861051271531842.6 6173881071291561882.8 6274891091321591913.0 637691111134162195

77

Table 12.5C.t values for 99.9% inactivation of Giardia lamblia by free chlorine at 20.0°Cand turbidity below 1 NTU.



<0.4 3644526274891050.6 3845546477921090.8 3946556679951131.0 3947566781981171.2 40485769831001201.4 41495870851031231.6 42505972871051261.8 43516174891081292.0 44526275911101322.2 44536377931131352.4 45546578951151382.6 46556680971171412.8 4756678199119 1 1433.0 47576883101122 1 146

Table 12.6CA values for 99.9% inactivation ofGiardia lamblia by free chlorine at 25.0°Cand higher, turbidity below 1 NTU.



<0.4 242935425059700.6 253036435161730.8 263137445363751.0 263137455465781.2 273238465567801.4 273339

1 4757

1 6982

1 1 .6 283340485870841.8 293441496072862.0 293541506174882.2 30.3542 1 516275902.4 303643526377922.6 313744536578942.8 313745546680963.0 32384655678197

78

Table 12.7CA values for 99.9% inactivation of Giardia lamblia cysts by chlorine dioxideand ozone with turbidity below 1 NTU.

Disinfectant TemperatureLess GreaterThan than1°C5°C10°C15°C 20°C25°C

Chlorine dioxide (mg/L).min632623191511Ozone(mg/L).min2.91.9__- 1.40.95 1 0.720.48

Table 12.8Disinfectant concentration and contact time for 90% inactivation ofCiyptospon di urn by chlorine dioxide and ozone with turbidity below 1 NTU.

(Concentration to be achieved after the contact time specified, in water leaving the contacttank)

DisinfectantContact timeChlorine dioxide1.3 (mg/L) for 1 hourOzone 1 (mg/L) for 5 minutes

79

13 TABLES OFMAVS

Table 13.1MAVs for micro-organisms of health significance

MICROORGANISMMAV

Faecal coliform Must not be detectable in 100 ml, of sample

Viruses No enteric viruses shall be detectable in 100L of sample.

Protozoa (pathogenic)Not detectable in 100L sample.

Hel minths (pathogenic)Not detectable in 1001, sample.

Algae No toxic algae present in lOmL of sample

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Table 13.2MAVs for inorganic determinands of health significanceNAME MAV UNITSREMARKS

Aluminium NADAntimony 0.003 mg/LArsenic 0.01mg/LFor excess lifetime skin cancer risk of 6 x

10-P, for practical quantitative analysis

Asbestos NADBarium 0.7 mg/LBeryllium NADBoron 0.3 mg/LBromate 0.025mg/LFor excess lifetime cancer risk of 7 x 10Cadmium 0.003 mg/LChlorate NADChlorine (free) 5mg/L as Cl,ATOChlorite 0.3mg/L as C102 P, disinfection must never be

compromisedChromium 0.05mg/LP. limited information on health effectsCopper 2 mg/LATOCyanide (total) 0.08mgILCyanogen chloride (as CN)0.08 mg/LDichioramine NADFluoride * 1.5mg/LIodine NADLead 0.01 mg/LManganese 0.5 mg/LATOMercury (total) 0.002mg!LMolybdenum 0.07 mgILMonochloramine 3 mg!LNickel 0.02mg/LNitrate 50 mg/LThe sum of the ratio of the

expressed asconcentrations of nitrate and nitriteNO3to each of their respective MAVs should

not exceed 1Nitrite 3mg/LThe sum of the ratio of the

expressed asconcentrations of nitrate and nitriteN 0to each of their respective MAVs should

not exceed 1.P, limited information on health effects

Potassium permanganate NADSelenium 0.01mg/LSilver USodium NADTin UTrichloramine NADUranium NAD

* The fluoride content recommended for drinking-water by the Public Health Commission for oral healthreasons is 0.7- 1.0 mg/L.

Abbreviations:P-Provisional MA'.'.NAD - No adequate data to permit recommendation of a health-based MAy.ATO - Concentrations of the substance at or below the health-based MAV may affect the appearance, taste or odour of the water.U -Unnecessary to recommend health-based MAV because they are not hazardous to human health at Concentrations normally

found in drinking water.

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Table 13.3MAVs for organic determinands of health significance

NAME MAV UNITSREMARKS

Acrylamide 0.0005mg/Lfor excess lifetime cancer risk of 10

Benzene 0.01mg/Lfor excess lifetime cancer risk of 10

Benzo[a]pyrene 0.0007mg/Lfor excess lifetime cancer risk of 10

Bromochloroacetonitrile NAD

Bromodichloromethane0.06mgILfor excess lifetime cancer risk of 10

Bromoform 0.1 mgILCarbon tetrachloride 0.002mg/LChloroacetone NAD

Chloroform 0.2mg/Lfor excess lifetime cancer risk of 10

2-Chlorophenol NAD

Chloropicrin NADDi(2-ethylhexyl)adipate 0.1mg/LDi(2-ethylhexyl) phthalate0.009mg/LDialkyltins NAD

Dibromoacetonitrile 0.2mg/LPDibromochioromethane 0.1 mg!LDichloroacetic acid 0.05mg/LPDichloroacetonitrile 0.1mgILP1,2-Dichlorobenzene 1 mg/LATO1,3-Dichlorobenzene NAD1,4-Dichlorobenzene 0.4mg/LATO1,1-Dichloroethane NAD1,2-Dichloroethane 0.03mg/Lfor excess lifetime cancer risk of 10

1,1-Dichioroethene 0.03mg/L1,2-Dichloroethene 0.06mg/LDichlorometharie 0.02mg/L2,4-Dichiorophenol NADEDTA 0.2 mg/LPEpichlorohydrin 0.0005mgILPEthylbenzene 0.3 mg/LATOFormaldehyde 1 mg/LHexachlorobutadiene0.0007mg/LMonochloroacetic acid NADMonochlorobenzene 0.3 mgILATO

MX NAD

Nit rilotriacetic acid 0.2mg/LPAH I I NAD

Styrene 0.03 1 mg/LATO

Abbreviations:p.Provisional MAV.NAD- No adequate data to permit recommendation of a health-based MAy.ATO-Concentrations of the substance at or below the health-based MAV may affect the appearance, taste or odour of the water.UUnnecessary to recommend health-based MAV because they are not hazardous to human health at concentrations normally


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Table 13.3MAVs for organic deterininands of health significance (CONT.)

NAME MAVUNITSREMARKS

Tetrachioroethene 0.05mg/LToluene 0.8mg/LATOTributyltin oxide 0.002mg!LTrichloroac eta ldehyde/ 0.01mg/LPchloral hydrateTrichioroacetic acid 0.1mgi'LPTrichioroacetonitrile 0.001mg/LPTrichlorobenzenes (total)0.03mg/LATO1,1,1-Trichloroethane 2mg/LPTrichioroethene 0.08mgILP2,4,6-Trichiorophenol 0.2mg/Lfor excess lifetime cancer risk of 10

ATOTrihalomethanes (THMs) The sum of the ratio of the

concentration of each to itsrespective MAV should not exceed 1

Vinyl chloride 0.005mg/Lfor excess lifetime cancer risk of10-s

Xylenes 0.61 mg/LI ATO

Abbreviations:P-Provisional MAy.NAD- No adequate data to permit recommendation of a health-based MAy.

ATO- Concentrations of the substance at or below the health-based MAV may affect the appearance, taste or odour of the water.U-Unnecessary to recommend health-based MAV because they are not hazardous to human health at concentrations normally


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Table 13.4: MAVs for pesticides


Alachlor 0.02mg/Lfor,excess lifetime cancer risk of 10Aldicarb 0.01mg/LAldrin/Dieldrin 0.00003mg/LAtrazine 0.002mg/LBentazone 0.03mg/LCarbofuran 0.006 mg/LChlordane 0.0002 mg/LChlorotoluron 0.04mg/LChlorpyriphos 0.07mg/L2.4-D 0.03mgIL2,4-DB 0.1mg/LDDT + isomers 0.002 mg/LDiazinon 0.01 mg/L1,2-Dibromo-3- 0.001mg/Lfor excess lifetime cancer risk of 10chloropropane1,2-Dichloropropane 0.02mg/LP1,3-Dichloropropane NAD1,3-Dichloropropene 0.02mgILfor excess lifetime cancer risk of 10Dichlorprop 0.1mg/LEthylene dibromide NADFenoprop 0.01 mgILHeptachlor and 0.00004mg/Lheptachlor epoxideHexachlorobenzene 0.001mg/Lfor excess lifetime cancer risk of 10Isoproturon 0.01mg/LLindane 0.002mg/LMCPA 0.002 mg/LMCPB NADMecoprop 0.01 mg/LMethoxychlor 0.02 mg/LMetolachlor 0.01mg/LMolinate 0.007mg/LPendimethalin 0.02mg/LPentachiorophenol 0.01mg/LPPermethrin 0.02mg/LPirimiphos methyl 0.1mg/LProcymidone 0.7 mg/LPropanil 0.02mg/LPyridate 0.1mg/L

Abbreviations:P-Provisional MAy.NAD - No adequate data to permit recommendation of a health-based MAV.ATO -Concentrations of the substance at or below the health-based MAV may affect the appearance, taste or odour of the water.U -Unnecessary to recommend health-based MAV because they are not hazardous to human health at concentrations normally


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Table 13.4MAVs for pesticides (cont.)


Simazine 0.002 mgIL

2,4,5-T 0.01mg/L

Terbuthylazine 0.02mg/L

Triclopyr j0.1 j mg!L

Trifluralin 0.03mgJL

1080 0.005 mg!LP

Abbreviations:P_Provisional MAy.NADNo adequate data to permit recommendation of a health-based MAy.ATO - Concentrations of the substance at or below the health-based MAV may affect the appearance, taste or odour of the water.U -Unnecessary to recommend health-based MAV because they are not hazardous to human health at concentrations normally


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Table 13.5MAVs for radiological determinands

RADIOACTIVE CONSTITUENTS MAV UNIT

Total Alpha Activity 0.10Bq/L, excluding radonTotal Beta Activity 0.50Bq/L, excluding potassium-40Radon 100 Bq/L

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Table 13.6Guideline Values for aesthetic determinands

DeterminandGuideline ValueUnitsComments

AggressivenessLSI > 0 CorrosionAluminium 0.15 mg/IDepositions, discoloration.Ammonia 1.5 mg/LOdour and tasteCalcium: see hardness mg/IChloride 250 mg/LTaste, corrosionChlorophenols mg/I

2-chlorophenol0.0001 Taste2,4-dichlorophenol 0.0003 Taste2,4,6-trichloro-0.002 Taste

phenolColour 10 TCUAppearanceCopper 1 mg/LStaining of laundry and sanitary ware

(health based provisional guidelinevalue 2 mg/L)

Eth.ylbenzene0.002 mg/LFor odour and taste (health basedguideline value 0.3_mg/L)

Hardness (total)200 mg/LHigh hardness causes scale(Ca + Mg) deposition, scum formation; low

hardness: possibly causes corrosionHydrogen sulphide0.05 mg/LOdour and tasteIron 0.2 mg/LStaining of laundry and sanitary wareMagnesium mg/I(see hardness)Manganese 0.05 mg/IStaining of laundry and sanitary wareOdour should be acceptable

to most consumersPH 6.5-8.5 Should be between 7.0 and 8.0. low

PH: corrosion; high pH: taste, soapyfeel. Preferably pH<8 for effectivedisinfection with chlorine

Sodium 200 mg/LTasteStyrene 0.004 mg/LFor odour and taste (health based

guideline value 0.03_mg/I)Sulphate 250 mg/LTaste, corrosionTaste should be acceptable

to most consumersTemperature should be acceptable

to most consumersToluene 0.024 mg/IOdour and taste (health based guideline

value 0.8 mg/I)Total dissolved solids1000 mg/LTasteTurbidity 2.5 NTUAppearance, for effective terminal

disinfection, median turbidity < 1 NTU,single sample _< 5 NTU

Xylene 0.02 mg/LOdour and taste (health based guidelinevalue 0.6 mg/I)

Zinc 3 mg/LAppearance, taste

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