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The
major categories of hazardous substances that are likely to
be found contaminating land are:
Arsenic:
Used
in some pesticides, presence of metalliferous mines.
Effects:
Toxic and carcinogen to humans.
Lead:
Leaded
petrol fumes, sewage sludge, some industrial waste, including
batteries.
Effects:
Toxic and carcinogen to humans. It is absorbed into the blood
stream and finally accumulates in the bones
Cadmium:
Used in paints. Often present as a contaminant in
zinc ore.
Effects: Toxic and carcinogen to humans |
Mercury:
Used
as pesticides. Also present in sewage sludge and some industrial
waste.
Effects:
Toxic and carcinogen to humans.
Petroleum
hydrocarbons: Pollution levels are due to
activities such as coal gasification, petroleum refining,
storage and dispensing, and combustion of fossil fuels.
Effects:
Toxic and carcinogen to humans.
Microbiological,
Animal or human sewage contamination: Pathogenic
bacteria may be harmful to humans. Landfill gases. Refuse disposal
sites.
Effects: Methane is highly explosive and carbon dioxide
is an asphixiant. Both gases in the soil can restrict plant
growth. |
