Environmental Engineering Reference
In-Depth Information
Table 9.1
Score system for characterizing the pollution sources at a mining site.
Estimated mass of the waste Toxic metal content of the waste
Physical state, weathering, pH
Metal concentration
Mass (tonnes)
Score
compared to SQCs (mg/kg)
Score Descriptive characterization
Score
<
10
2
SQC2
>
one metal
>
SQC1
1
Non-weathered waste rock
1
10-100
3
SQC2
>
two metals
>
SQC1
2
Non-acidic flotation tailings
2
100-1000
4
SQC2
>
several metals
>
3
Lime precipitate in sediment
2
SQC1
1000-10,000
6
SQC3
>
one metal
>
SQC2
5
Dispersed flotation tailings
3
10,000-100,000
8
SQC3
>
two metals
>
SQC2
6
Partly leached flotation
4
tailings
100,000-1,000,000
9
SQC3
>
several metals
>
7
Contaminated sediment
5
SQC2
>
1,000,000
10
one metal
>
SQC3
8 Weathered, acidic
6
waste rock
two metals
>
SQC3
9
Sediment on soil
8
several metals
>
SQC3
10
Vegetated contaminated soil
8
Bald, barren soil
9
Weathered acidic waste
10
Scoring or percentage tuning may be fully qualitative based on experts' judgment
and scoring, or semiquantitative, based partly or fully on quantitative information.
Information which is different in dimensions and weightings, even if there is quantita-
tive data, cannot be compared with each other or aggregated. It should be placed onto
a relative scale (e.g., as a percentage) before aggregation.
As an example: a detail of a relative score system is shown for the assessment of
several dozen mine waste disposal sites in Hungary (Table 1).
Mass and metal content are quantitative, whereas physical state, weathering, and
mobility are qualitative characteristics. The scores in the table are relevant for the
sources; similar scores will characterize the transport routes and the receptors (ecosys-
tem and humans). Finally the scores are added, and the waste disposal sites ranked
(see also Volume 5).
4.1.2 Quantitative RA
Quantitative RA equally relies on the characteristics and hazards of the hazardous
physical agents or chemical substances and the characteristics of the environment and
its users. The same hazardous chemical may pose a different scale of risk in water and
soil, in indoor or outdoor air, to plants or humans, to microorganisms or animals, etc.
Air flow, surface water, soil and groundwater geochemistry and hydrogeology, topog-
raphy of the endangered land, pH and redox potential of the environment, etc. are
extremely important characteristics in the development of environmental risk because
the chemicals and the environment, their interaction with the physical phases and the
living organisms are responsible for the manifestation of the risk from existing hazards.
The physical and chemical characteristics of a chemical substance may be completely
different under different environmental conditions. For example, sulfide minerals
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