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ASSESSMENT OF HAZARDOUS PROPERTIES AND THE CLASSIFICATION OF MINING WASTE FACILITIES: EUROPEAN UNION AND AFRICAN EXPERIENCE
Bohdan Kříbek Czech Geological Survey,
Klárov 313, Prague, Czech Republic
IGCP/SIDA 594 Training course, University of the Witwatersrand, Johannesburg, July 13-15, 2013
Directive 2006/21/EC of the European Parliament and of the Council of March 15, 2006 on
the management of waste from the extractive industries and amending Directive 2004/35/EC
(the Mining Waste Directive)
Category A (hazardous waste facilities) and Category non-A (non-hazardous waste facilities)
A waste facility shall be classified under category A, if:
a) a failure or incorrect operation, e.g. the collapse of a heap or the
bursting of a dam, could give rise to a major accident, on the basis of a
risk assessment taking into account factors such as the size, the
location and the environmental impact of the facility; or
b) it contains waste classified as hazardous under Directive 91/689/EEC
above a certain threshold; or
c) it contains substances or preparations classified as dangerous under
Directives 67/548/EEC or 1999/45/EC above a certain threshold.”
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
STAGES OF THE ASSESSMENT Stage I: Pre-selection characteristics of closed waste facilities Stage II: Assessment of hazardous properties of wastes and their impact on the environment (pre-feasibility study) Stage III: Assessment of hazardous propries of wastes and their impact on the environment –Feasibility study (EIA) and Risk assessment (ERA)
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
Stage I: Pre-selection characteristics of closed waste facilities
Pre-Selection Protocol Flowchart
STAGE I: PRE-SELECTION PROTOCOL (PART I)
1. General data
1.1. Name of researcher, company, site code number 1.2 Facility owner, owner code number
1.3 District/Province/State/Country 1.4 General type of landscape use (agriculture, forest, industrial, residential)
1.5 Topographic data (including terrain data from contour lines or digital elevation model)
1.6 Census data
1. 7 Status classification (existing monitoring data and river basin management plans of surface and groundwater bodies, land-use plans)
2. Waste facility type
2.1 Waste rock heaps: (heap, pond, backfilling of old excavation voids, backfilling of operation strip mines or operated underground mines)
2.3. Tailings: (backfilling of tailings into operating mines, tailing ponds, rxisting open pits and depressions, valley impoundment, off-valey impoundment)
2.2. Waste monitoring system (drainage, collection ditches, monitoring wells)
3. Basic waste facility data (site data)
3.1 Area (m2) 3.2 Volume (m3)
3.3. Height, thickness 3.4. GPS X, Y, Z coordinates
3.5. Coordinates system, map datum 3.6 Accuracy of measurement
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
STAGE I: PRE-SELECTION PROTOCOL (PART II)
4. Geology
4.1 Rock type 4.2 Grain size
4.3 Mineralogy (primary and secondary minerals) 4.4 Possibility of waste use (re-use, construction purposes, aggregates, soil amendment, others)
5. Current stage of remediations
5.1 Current state (in use, re-processed, closed, abandoned, remediated, unremediated, not known)
5.2 Date of the facility closure
5.3 Remediation measures description:
6. Wastes related incidents in the past (dam failure, massive river water or groundwater contamination, cattle or fish mortality, others)
7. Contents of potential harmful chemical elements and materials in waste
7.1. Sulfides, AMD producing, non-AMD producing agents
7.2. Potentially harmful metals, metalloids and materials (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Te, Tl, U, V, Zn, asbestos)
7.3. Dangerous substances (cyanide, mercury, flotation agents)
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
8 Stability of waste facility
8.1 Tailings, area of lagoon (m2) 8.6. Slope of the waste heap
8.2 Tailings lagoon description 8.9. Slope of the waste heap foundation
8.3. Height of the tailing lagoon surface relative to surface outside facility
8.4. Slope of the tailings dam
8.5 Slope of the foundation
9 Pathways of dispersion
9.1. Wastes erosion, watercourses siltation, overflow, seepage
9.2. Permeability of layer beneath the mine waste of tailings facilities
9.3. Exposition of waste material to the wind (vegetation cover)
9.4. Waste cover type (water, slag, laterite, bitumen, soil) and cover thickness
10 Recepients
10.1. Location of settlement (single houses, communities, villages)
10.2. Agricultural land, livestock, fishery
10.3. Water resources (wells, water reservoirs)
10.4. Data on location of areas protected by legislation (National parks, games, points of interests etc.)
10.5. Any other known serious impacts
STAGE I: PRE-SELECTION PROTOCOL (PART III)
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
11 Other data
11.1. Conflict of interests (water reserves, electricity lines, gas lines, land-use plans, military facilities)
11.2. Access to the site
11.3. Possibility to collect samples (without technical works, with light technical works, excavator, drilling only)
12 Recommendation (examine further – no need to examine further)
Date, signature Annexes: Maps, photographs, list of samples
STAGE I: PRE-SELECTION PROTOCOL (PART IV)
Mufulira Tailing Pond, Zambia Chambishi waste heap, Zambia
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STAGE I, SOURCES OF INFORMATION: Mine operators, geological surveys, municipalities, LANDSAT, Google Earth, aerial photographs, field survey..
Class km2 %
Jarosite 0.008 0.075
Goethite 0.109 1.005
Lignite 1.126 10.374
Granite + Clay 3.385 31.184
Clay 6.226 57.362
Total 10.853 100
Example:
Hyperspectral
imagery (Satelite and airborne
data and ground
verification)
Sokolov Coal Basin, Czech Republic
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
Gypsum precipitates Active drainage
Stream contamination
Example of airborne survey:
Mine waste heap, Chingola, Zambia
STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – SAMPLING
Recipientecosystems
Well
Agriculturalfields, pastures
Impermeable underlying rocks
Groundwater level
Physical and chemical processes:
I. Physical and chemical weathering (mechanical disintegration, secondary minerals)II. Sulfides oxidation, carbonate dissolution, acidificationIII. Waste burning (coal), redistribution of metals and metalloids
Sampling sites:
1) Background (springs, watercourses, hydrogeological wells, test pits, bored wells)
2) Waste material (hand-picked average samples, test pits, drilling)
3) Transpoprt pathways (seepage, run-off sediments bored pits, boreholes hydrogeological wells, control wells
4) Risk recipients
Transport pathways:
A) Groundwater
B) Rainwater and rain wash
C) Dust
1)1)
STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – TYPE OF SAMPLES AND SAMPLING DENSITY
a) BACKGROUND SAMPLING (springs, wells, soils, agricultural prouducts,
grass) (5-30 samples) b) WASTE MATERIAL SAMPLING (hand-picked average samples, test pits (1-2 m depth) shallow drilling (3-7 m depth), waste water (3-5 samples) c) TRANSPORT PATHWAYS SAMPLING (water run-off sediments, seepages, water from bored pits,boreholes, hydrogeological wells, control wells) (sampling wherever possible) d) RISK RECIPIENTS SAMPLING - soils (30- 50 samples) - agricultural products and grass (10-20 samples) - surface water (10 –20 samples) - stream sediments (10-20 samples) - water wells (sampling wherever possible)
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STAGE II: ASSESSMENT OF HAZARDOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – CHEMICAL ANALYSES
(1) Neutralization potential ratio (NPR) = NP/AP
Where: NP (neutralisation potential) = kg CaCO3/t * 10 waste (calculated from Ctot-Corg =
Ccarb)
Where: AP (acid potential) = Total S (wt.%)* 31.25
For NP/AP > 3, the waste is considered non- acid generating (non-A waste)
between 3-1 uncertainity interval, less than 1: acid generation waste (A-waste)
Analytical procedure: CEN/TC 292/WG
May be substituted by the determination of the net neutralization potential (NNP):
NNP = NP-AP
NNP values > 20 kg CaCO3/t of waste (non A waste)
NEP values < 20 kg CaCO3/t of waste (A-waste)
Analytical procedure after Sobek
WASTES SAMPLING ACCORDING TO EU REGULATIONS
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STAGE II: ASSESSMENT OF HAZARDOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – CHEMICAL ANALYSES
(2) The content of hazardous substances (Ag, As, Ba, Be, Cd, Co, Cr, Cu, Hg,
Ni, Pb, Sb, Se, Sn, Te, Tl, U, V, Zn or asbestos) Checking the content of various substances against the threshold values defined by the hazard properties (H1-H14) in Annex III to Directive 91/689/EEC and the risk phases defined in Directive 2001/59/EC).
(3) The content of substances or preparations classified as dangerous (cyanide, phenols, flotation agents)
Checking the content of substances classified as dangerous under Directives 67/548/EEC or 1999/45/EC
WASTES SAMPLING ACCORDING TO EU REGULATIONS
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – THRESHOLD VALUES
THRESHOLD VALUES (a) one or more substances classified as very toxic at a total concentration ≥ 0.1 %, (b) one or more substances classified as toxic at a total concentration ≥ 3 %, (c) one or more substances classified as harmful at a total concentration ≥ 25 %, (d) one or more corrosive substances classified as R35 at a total concentration ≥ 1 %, (e) one or more irritant substances classified as R41 at a total concentration ≥ 10 %, (f) one substance known to be carcinogenic of category 1 or 2 at a concentration ≥ 0.1 %, (g) one substance toxic for reproduction of category 1 or 2 classified as R60, R61 at a concentration ≥ 0,5 %, (h) one mutagenic substance of category 1 or 2 classified as R46 at a concentration ≥ 0.1%,
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – CHEMICAL ANALYSES
EUROPEAN UNION THRESHOLD VALUES ARE BASED ON PROPERTIES AND CHARACTERISTICS OF DANGEROUS CHEMICAL SUBSTANCES CLASSIFIED AS HAZARDOUS DANGEROUS PROPERTIES OF MINERAL PHASES ARE NOT AVAILABLE THEREFORE, MEMBER STATES OF THE EUROPEAN UNION USE
THRESHOLD VALUES FOR REGIONAL SCREENING OF SOIL
CONTAMINATION INSTEAD
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THRESHOLD VALUES FOR SOIL CONTAMINATION: Holland, Canada
Holland Canada, soils (mg/kg)
Soil/Sediment,
Action (mg/kg)
Groundwater,
Action (mg/l)
Agricultural
use
Residential
use
Commercial
use
Industrial
use
As 55 60 12 12 12 12
Ba 625 625 500 500 750 2000
Cd 12 6 1.4 10 10 22
Cr (tot) 380 30 64 64 64 87
Cu 190 75 63 63 63 91
Pb 530 75 70 140 140 600
Ni 210 75 50 50 50 50
Hg 10 0.3 6.6 6.6 6.6 50
Zn 720 800 200 200 200 360
Cyanide
(free)
20 1500 0.9 0.9 0.9 8
STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
Holland (Dutchlist) http://www.axys.cz/doc/en/Dutchlist.pdf
http://www.rivm.nl/en
United Kingdom http://www.doh.gov.uk
http://www.defra.gov.uk/environment/land/contamined/index.htm
United States http://www.epa.gov/ecotox/ecossl/
http://www.epa.gov/oswer/riskassessment/index.htm
http://www.epa.gov/ecptpx
Canada http://www.ccme.ca/publication/list_publications.html
Australia http://www.dec.wa.gov.au/contaminatedsites
New Zealand http://contamsites.landcareresearch.co.nz/about.htm
http:www.mfe.govt.nz/publications/hazardous/
World Health http://www.who.int/en/
Organisation
(ES dat) - comparison http://www.esdat.com.au (and go to Environmental standards)
USEFUL DOCUMENTS
THRESHOLD VALUES FOR SOIL CONTAMINATION
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT
(1) pH of collected mine waste water (tailings ponds) (2) pH of water leachate of wastes (3) Chemical composition and physical properties of waste water leachate (static and kinetic tests) (4) Ecotoxicity of waste water leachate (5) Metals partitioning (sequentional analyses)
ADDITIONAL CHEMICAL AND BIOLOGICAL METHODS
OF WASTE SAMPLING
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – EXAMPLE – KABWE WASTES, ZAMBIA
Residuum from chemical leaching of lead and zinc ores and decant drain precipitates, Kabwe, Zambia
Flotation tailings after treatment of lead and zinc ores, Kabwe, Zambia
Leaching residuum
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – EXAMPLE – KABWE WASTES – STATIC LEACHING TEST (According to the Directive 1999/31/EC („Landfill Directive“),
Settling pond at plant for
chemical treatment of copper
and cobalt ores ofthe Sable
Zinc Plc. at Kabwe, Zambia,
with efflorescence of cobalt
and copper salts.
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – EXAMPLE – KABWE WASTES – STATIC LEACHING TEST (According to the Directive 1999/31/EC („Landfill Directive“)
EU limits (mg/kg of dry substance)
L/S 2l/kg, static test
Kabwe wastes, Zambia (mg/kg) L/S 2l/kg, static test
Element
Inert waste
Hazardous waste at land fills for nonhazardous waste
Hazardous waste for landsfillls for hazardous waste
Decant drain from chemicaly leached waste
Chemical leaching residuum
Flotation tailings
Active tailings after chemical leaching
As 0.1 0.4 6 0.06 < 0.05 < 0.005 0.06
Cd 0.03 0.6 3 5.15 0.204 0.204 0.352
Cr -tot 0.2 10 25 0.01 < 0.005 0.005 0.04
Hg 0.003 0.05 0.5 < 0.001 < 0.001 < 0.001 < 0.001
Ni 0.2 5 20 1.4 < 0.02 < 0.02 9.09
Pb 0.2 5 25 2.64 0.26 0.26 0.159
Se 0.06 0.3 4 0.62 < 0.05 < 0.05 0.451
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – EXAMPLE - ACUTE ECOTOXICITY TEST – ROSH PINAH, NAMIBIA
The windblown dust from the tailings dam is a potential environmental problem at the Rosh Pinah Town
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Experimental stabilization of
tailings dam slopes
Dust storm over the Rosh
Pinah Town
STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – EXAMPLE - ACUTE ECOTOXICITY TEST – ROSH PINAH, NAMIBIA
Test type Limit value Samples Rosh Pinah, Namibia
RP-1 RP-2 RP-3 RP-4
Immediate toxicity
Tested on aquarial fish
(Poecilia reticulata)
Average mortality: max. 5 % 0 0 0 % 0 % 0 %
Immediate toxicity tested on water fleas
(Daphnia magna)
Average
immobilization max. 30 %
85 % 92% 100 % 93 %
Test on freshwater algae Average inhibition or stimulation:
max 30 %
10.3 % 12.4 % 32.7 % 33.1 %
Test on seeds of higher plants
(Sinapis alba)
Average inhibition or stimulation:
max. 30 %
22.6 % 4.9 % 4.3 % 15.1 %
Bacterial bioluminiscence test
(bacteria Vibrio fisheri)
Average stimulation or inhibition: max: 30 %
12.4 % 12.6 % 9.3 % 10.1 %
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STAGE II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – PRELIMINARY RISK ASSESSMENT
PRELIMINARY RISK ASSESSMENT - INCIDENTS
LOW RISK INTERMEDIATE RISK
HIGH RISK
INCIDENTS IN THE PAST
Without incidents
Small incidents affecting environment within a specified distance from the facility (< 1 km)
Loss of human life or incidents affecting environment in extent larger than a specific distance from the facility (> 1 km)
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Stage II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – PRELIMINARY RISK ASSESSMENT
PRELIMINARY RISK ASSESSMENT – CHEMICAL PROPERTIES OF WASTES
LOW RISK INTERMEDIATE RISK HIGH RISK
Neutralization potential ratio
> 3 3-1 < 3
Content of specified substance
Not exceeding threshold limit values for Ag, As, Ba, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Te, Tl, U, V, Zn, asbestos
Exceeding threshold limit values in the same concentration range
Exceeding threshold limit values in higher concentration ranges
Content of dangerous chemicals
Not exceeding threshold
Limit values
Exceeding threshold(s) in the same concentration range
Exceeding threshold(s) in higher concentration ranges
Leachability Not exceeding threshold(s) for innert waste
Not exceeding thresholds for hazardous wastes
Exceeding thresholds for hazardous wastes
Ecotoxicity Not exceeding thresholds Exceeding some thresholds
Exceeding all thresholds
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Stage II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – PRELIMINARY RISK ASSESSMENT
PRELIMINARY RISK ASSESSMENT – GEOTECHNICAL PROPERTIES OF WASTES
LOW RISK INTERMEDIATE RISK HIGH RISK
Tailings lagoon size < 5000 m3 5 000-10 000 m2 > 10 000 m2
Height of tailings lagoon relative to the landscape altitude 50 m from the dam
< 2 m 2-4 m > 4 m
Inclination of the foundation < 3o 3-5o > 5o
Overal waste heap slope < 20o 20-30o > 30o
Height of waste heap < 10 m 10-30 m > 30 m
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Stage II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – PRELIMINARY RISK ASSESSMENT
PRELIMINARY RISK ASSESSMENT – IMPACTS ON THE ENVIRONMENT
LOW RISK INTERMEDIATE RISK HIGH RISK
Surface water Not exceeding
thresholds for surface water
Exceeding threshold(s) for surface water within 1 km of the
waste facility
Exceeding threshold(s) for surface water more than 1 km
of the waste facility
Potable water Not exceeding thresholds for potable water
Exceeding threshold(s) for potable water
within 500 from the waste facility
Exceeding threshold(s) for potable water more than 500
m from the waste facility
Stream sediments Not exceeding thresholds for
stream sediments
Exceeding threshold(s) for surface water
within 2 km from the waste facility
Exceeding threshold(s) for surface water more than 2 km
from the waste facility
Agricultural products and pasture grass
Not exceeding threshold(s)
Exceeding threshold(s) within 500 m from the
waste facility
Exceeding threshold(s) more than 500 m from the waste
facility
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Stage II: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND THEIR IMPACTS ON THE ENVIRONMENT – PRELIMINARY RISK ASSESSMENT
PRELIMINARY RISK ASSESSMENT – IMPACTS ON THE ENVIRONMENT
LOW RISK INTERMEDIATE RISK HIGH RISK
Soils
A) Agricultural land-use
B) Residential land-use
C) Commercial land use
A) Industrial land use
Not exceeding
threshold(s) for single land use
category
Exceeding threshold(s) for individual land use categories within 1 km from the waste facility
Exceeding threshold(s) for
For individual land use more than 1 km from the waste
facility
Dust Not exceeding threshold(s)
Exceeding short-term threshold values (24
h) for total suspended particles or particlles
PM10 or PM2.5
Exceeding long-term threshold values for total suspended
particles, MP10 or MP2.5 particles
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
STAGE III: ASSESSMENT OF HAZARDEOUS PROPERTIES OF WASTES AND
THEIR IMPACTS ON THE ENVIRONMENT - FEASIBILITY STUDY (EIA) AND RISK
ASSESSMENT (ERA)
In a technical risk-based discipline, risk is often defined as the combined effect of the likelihood of a harmful event to occur (caused by a hazard), and the magnitude of the caused harm.
Two fundamental phases are involved: risk assessment and risk management.
RISK ANALYSIS
Risk Assessment
Hazard identificaltionDose-response assessment
Exposure assessment
Risk characterisation
Risk Management
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Examples of risk assessment models
The European Union TAC-model The criteria and limit values for acceptance of waste at landfills for inert, non-hazardous and hazardous waste landfills was set based on a risk assessment procedure developed by the TAC Subcommittee on the Landfill Directive.
VROM (The Dutch Directorate General for the Environment) Dutch soil remediation policy (VROM, 1994) uses soil remediation intervention values, indicative levels for serious contamination and target values.
SEPA (The Swedish Environmental Protection Agency) Humans and eco-systems are exposed to contaminants in several ways. The potential exposure pathways are considered when developing national generic guideline values for concentration of substances in soil. These are based on the principles for deriving SSLs (Soil Screening Levels) as described by the US EPA (US EPA, 1996b). In Sweden, seven exposure pathways have been included in the human exposure model
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Examples of risk assessment models
US EPA Superfund risk assessment Human Health risk assessment The US EPA issued an initial set of five risk assessment guidelines for human health in 1986, relating to cancer, mutagenic effects, developmental effects, exposure assessment, and chemical mixtures, Ecological risk assessment (ERA) ERA process evaluates the likelihood (although not always quantitatively) that adverse ecological effects are occurring or may occur as a result of exposure to one or more stressors.
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
US EPA Human Health Risk Assessment
EXAMPLE: DOSE CALCULATION – DUST INGESTION
Quantification of dose must be complex and must be undertaken by an expert in human health risk
assessment.
The generic equation for calculating of average daily intake (ADI), dust ingestion:
IGCP-SIDA 495 Training Course, Johannesburg, July 13-15, 2013
Notes:
ADI is calculated for non-chronic, non-cancer effects.
Exposure duration is the lenght of time of contact with contaminant.
ADI = C x IR x ED x EF
Body Weight x AT
Where: = Concentration of the contaminant (mg kg-1) = Intake Rate (mg day-1) = Exposure Duration (years) = Exposure Frequency (days year-1) = Averaging Time (days)
CIREDEFAT
US EPA Human Health Risk Assessment
The dermal absorbed dose (DAD) is calculated as:
EXAMPLE: DERMALLY-ABSORBED AVERAGE DAILY INTAKE
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Note: For non-carcinogenic effects, AT = AD x 365 days year-1 (U.S. EPA, 2004)
DAD = (Cdust x CF x AFwtd x EV x ED x EF x SA)
Body Weight x AT
Where: = Event frequency (events day-1) = Exposure Duration (years) = Exposure Frequency (days year-1) = Skin surface area available for contact (cm2) = Averaging Time (days)
= Concentration of the contaminant (mg kg-1)CF = Conversion factor (10-E6 kg mg-1)AF = Adherence factor of soil/dust to skin (mg cm-2 event-1)
EVEDEFSAATCdust
wtd
US EPA Human Health Risk Assessment
EXAMPLE: CALCULATION OF HAZARD QUOTIENT FOR THE DERMAL ROUTE:
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Note: The estimate of total risk for exposure to soil/dust contaminants (HQdust)
is based on the summation of individual risks for the oral and deraml routes.
HQ =dermal
DAD
RfDABS
Where: HQ =
RfD
dermal
ABS
The hazard quotient for the dermal routeDAD = Dermal absorbed dose (mg kg day-1)
= Absorbed reference dose (mg kg day-1)
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EXAMPLE:
ESTIMATED DAILY INTAKE
OF COBALT
IN THE KATANGA MINING
DISTRICT,
D. R. CONGO
“African copperbelt”
Kamina
26 0’0’’
E
28 0’0’’
E
10 0’0’’
S
12 0’0’’
S
Likasi Lumumbashi
Kipushi
C. Banza Lubaba Nkulu1, K. Cheyns, J. Ngoy Asosa, L. Kabamba Ngombe et al., 2012,
C. Banza Lubaba Nkulu1, K. Cheyns, J. Ngoy Asosa, L. Kabamba Ngombe et al., 2012
55 62 62 65
635 509 553 593
99 170 79
Copperbelt: Estimated Co intake (µg/day) – Adults
C. Banza Lubaba Nkulu1, K. Cheyns, J. Ngoy Asosa, L. Kabamba Ngombe et al., 2012
Copperbelt: Estimated Co intake (µg/day) – Children
29 36 33 34
352 416 340 313
46 34 37
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You can learn more about the assessment of hazardous properties of mining waste facilities at:
THE RISK ASSESSMENT MANUAL OF ABANDONED MINE SITES
prepared by the Geological Survey of Namibia
CONCLUSIONS
1. In the first stage information on waste facilities are collected. Sources
of information include official report from the former operator of respective
mine, Geological Survey professional papers and reports, media reports,
knowledge of the assessor, etc. As a part of this stage may be (but not
necessarily), basic chemical tests (determination of neutralization potential
ratio, and aproximate determination of the content of dangerous
substances),
2. The second stage (pre-feasibility study) includes assessment of
chemical and geotechnical properties of wastes, assessment of transport
pathways of contamination, evaluation of the impact of contamination on
potential recipients and a draft design of the remediation of storage site.
3. In the third stage (feasibility study) an environmental impact
assessment (EIA) and risk assessment study are carried out and a
comprehensive proposal for redevelopment/remediation of storage site
including technical design and budget of anticipated work to be undertaken
are worked out.
Evaluation of hazardous properties of mine waste faclities takes place in three stages:
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Thank you for your attention