water quality sampling

7/27/2019 Water Quality Sampling

1/11

WATER QUALITY SAMPLING


2/11

WATER QUALITY

Water quality refers to the chemical, physical andbiological characteristics of water. It is a measure of

the condition of water relative to the requirements of

one or more biotic species and or to any human need

or purpose. It is most frequently used by reference to aset of standards against which compliance can be

assessed. The most common standards used to

assess water quality relate to health of ecosystems,

safety of human contact and drinking water.


3/11

In the water industry:

Water Sampling and Analysis ensures water is of aquality and standard appropriate to its use and

determines the treatment processes required to ensurethe supply of safe water

The accuracy of water analysis is dependent on thesampling method used, the time elapsed betweensampling and analysis, the techniques used in laboratory

analysis and interpretation of the results. There are alsostandards governing water sampling frequency andtechniques/methodology used.

In the setting of standards, agencies make political and

technical/scientific decisions about how the water will beused. In the case of natural water bodies, they alsomake some reasonable estimate of pristine conditions.Different uses raise different concerns and thereforedifferent standards are considered. Natural water bodies

will vary in response to environmental conditions.


4/11

CATEGORIES

THE PARAMETERS FOR WATER QUALITY ARE DETERMINED BY

THE INTENDED USE. WORK IN THE AREA OF WATER QUALITY

TENDS TO BE FOCUSED ON WATER THAT IS TREATED FOR HUMANCONSUMPTION, INDUSTRIAL USE, OR IN THE ENVIRONMENT.

Human consumption

Contaminants that may be in untreated water

include microorganisms such as viruses and bacteria;inorganic contaminants suchas salts and metals; organic chemical contaminantsfrom industrial processes and petroleumuse; pesticides and herbicides; and radioactive

contaminants. Water quality depends on the localgeology and ecosystem, as well as human uses suchas sewage dispersion, industrial pollution, use of waterbodies as a heat sink, and overuse (which may lowerthe level of the water).


5/11

INDUSTRIAL AND DOMESTIC USEDissolved minerals may affect suitability of water for a range

of industrial and domestic purposes. The most familiar of

these is probably the presence of ions of calcium and

magnesium which interfere with the cleaning action of soap,

and can form hard sulfate and soft carbonate deposits inwater heaters or boilers. Hard water may be softened to

remove these ions. Hard water may be preferable to soft

water for human consumption, since health problems have

been associated with excess sodium and with calcium and

magnesium deficiencies. Softening decreases nutrition and

may increase cleaning effectiveness.


6/11

ENVIRONMENTAL WATER QUALITY

Environmental water quality, also called ambient water

quality, relates to water bodies such as lakes, rivers, and oceans.

Water quality standards for surface waters vary significantly due to

different environmental conditions, ecosystems, and intended

human uses. Toxic substances and high populations of certain

microorganisms can present a health hazard for non-drinking

purposes such as irrigation, swimming, fishing, rafting, boating, and

industrial uses. These conditions may also affect wildlife, which use

the water for drinking or as a habitat.


7/11

There is some desire among the public to return waterbodies to pristine, or pre-industrial conditions. Mostcurrent environmental laws focus on the designation ofparticular uses of a water body. In some countries thesedesignations allow for some water contamination as long

as the particular type of contamination is not harmful tothe designated uses. Given the landscape changes inthe watersheds of many freshwater bodies, returning topristine conditions would be a significant challenge. Inthese cases, environmental scientists focus on achieving

goals for maintaining healthy ecosystems and mayconcentrate on the protection of populationsof endangered species and protecting human health.


8/11

SAMPLING AND MEASUREMENT

The complexity of water quality as a subject isreflected in the many types of measurements ofwater quality indicators. The most accuratemeasurements of water quality are made on-site,because water exists in equilibrium with itssurroundings. Measurements commonly made on-site and in direct contact with the water source in

question include temperature, pH, dissolvedoxygen, conductivity, oxygen reduction potential(ORP), pH, etc.


9/11

WATER QUALITY EQUIPMENTS AND SAMPLING

PROCEDURES

Equipment and sampling for water quality arehighly specialized.

Special procedures are required for samples to

be analyzed for heavy metals or trace organicsto avoid contamination, oxidation, or adsorptionto the sampling equipment.

The U.S. Geological Survey has published a

series of manuals dealing with sampling andanalysis procedures for storm-water runoff,receiving water, and groundwater.


10/11

An automated sampling station installed

along the East Branch Milwaukee

River,New Fane, Wisconsin. The cover of

the 24-bottle autosampler (center) is

partially raised, showing the samplebottles inside. The autosampler was

programmed to collect samples at time

intervals, or proportionate to flow over a

specified period. The data logger (white

cabinet) recorded temperature, specific

conductance, and dissolved oxygenlevels.

A rosette sampleris used to

collect samples in deep water,

such as the Great Lakes or

oceans, for water quality testing.
http://en.wikipedia.org/wiki/File:WQ_sampling_station_USGS_2004.jpghttp://en.wikipedia.org/wiki/File:WQ_sampling_station_USGS_2004.jpghttp://en.wikipedia.org/wiki/File:Rosette_sampler_EPA.gif


11/11

A gas chromatograph-

mass

spectrometermeasures pesticid

esand other organic polluants

An electrical conductivity

meter is used to

measure total dissolvedsolids
http://en.wikipedia.org/wiki/File:Electrical_conductivity_meter.jpghttp://en.wikipedia.org/wiki/File:GCMS_open.jpg

water quality sampling

Documents