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Contaminated Site Clean-up
Industrial, agricultural, recreational, domestic and waste disposal
activities
introduce "contaminants" into air, water and soil.
This section of
the website provides some information about soil or land contamination and
efforts that have been used and are being continuously used to clean up the
contamination so as to prevent adverse effects on humans and the
environment.
According to the United States
Environmental Protection Agency (USEPA), a
contaminant is any physical,
chemical, biological, or radiological substance or matter that has an
adverse effect on air, water, or soil.
A used and/or abandoned site, following censure of activities or
abandonment often contain several contaminants that pose immediate hazards
or are capable of posing future hazards to human and ecological heath. The
contaminants (e.g. chemical substances) pose hazards because they exist at levels
above the background levels or they exceed certain levels, pre-determined to
be protective of human and ecological health. The pre-determined levels or
"thresholds" or "cutoffs" or "clean-up criteria" are set by authorities
having jurisdiction over a given community.
Contaminated (or Environmental) Site
Assessment (ESA) studies are required to establish the extent and
magnitude of contamination on a site. The established magnitudes are
compared to the pre-determined safe levels (clean-up) criteria to decide on
whether or not a site is contaminated and delineate (or mark out) areas of
contamination on a site.
In cases of these exceedances of the
background concentrations or the pre-determined levels, site clean up is
required to reduce the contaminants to levels considered safe for human
health and the ecology. This is particularly so where the used land will be
reused for future projects or where there will be continuous access to the
site by humans and animals.
An action plan (Remedial
Action Plan (RAP)) is developed following the site assessment studies. The
RAP identifies the remediation approaches that
are appropriate for the clean-up of the different streams of wastes on a
site.
Site Clean up or
Remediation involves the removal, reduction, immobilization or
neutralization of contaminants on a contaminated site to minimize the
adverse effects of the contaminants on public health/safety and the effects
on the environment.
Remediation/Clean-up
procedure involves several stages involving:
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Characterization -
identification of the various contaminants at the site. This typically occur
in three phases I, II and III. The result of a previous phase determines the
need to go to the next phase.
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Delineation - defining the extents
(laterally and vertically) of the contaminations. The concetrations of
contaminats determined from stage 1 is compared to the preset "threshold"
levels to determine the areas and levels of exceedances. Where the
thresholds are exceeded, there would be need for remediation/clean-up. The volumes or other quantitative measures
of exceedances would have to be determined as well.
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Planning (developing a Remedial Plan and
costing) - identifying the various options for clean up (remedial
technologies), choosing a method (s) of clean up appropriate, costing the
chosen approach/approaches
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Actual remediation - Implementation of
the plan using the chosen remedial technologies
Site cleanup technologies
reduce the contaminant levels or the levels of risks on used sites to levels
pre-specified, by regional standards or site specific studies, as protective
of humans and ecology.
Follow the links to the left for
introductory information on Environmental Site Clean up including sections
features on contaminated sites, common chemical contaminants, and the remediation technologies for reducing the common
contaminants.
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