Environmental Analysis Tools - Environmental Impact Analysis: Process and Methods - page 283

Ecological principles, related to NEBA (see Section 7.3), have been used to
address this “hot spot and ingestion risk” scenario.
The approach is to reduce the proportion of contaminated prey items in the
carnivore's diet by two processes. One is to increase the habitat value of the rela-
tively uncontaminated portions of the site by actions in the clean areas such as:
r Planting and maintaining species that are prime food or cover for
the prey items
r Removing invasive plant species that inhibit prey species presence
and density
r Creating habitat features, such as nesting areas attractive to prey species
r Providing a limiting habitat requirement such as water or salt.
Increasing the attractiveness of the relatively uncontaminated portions of
the site to the prey species will result in higher density food sources in these
areas. The carnivores forage and feed preferentially in these areas of rela-
tively uncontaminated prey and thus lower the ingestion dose of contami-
nants and proportionally reduce the risk.
The area of highest contamination can be rendered less attractive to forg-
ing carnivores and produce the same result of reducing contaminant inges-
tion and associated risk. This can be done through a combination of very
limited and nondestructive removal of contaminated media from the “hot
spot” and/or reducing the habitat value of the remaining areas of elevated
contamination. In line with the concept of NEBA, the reduced habitat value
should be replaced with an improved value in the uncontaminated area such
that the food quantity available to the carnivore is at least equal to the pre-
remediation quantity and of better quality. Of course, the two approaches—
cleaning and limiting prey quantity in contaminated areas and improving
prey density in clean areas—can be used in combination to result in a con-
taminant dose posing no risk to the carnivore.
7. 2 .9 AJ Mine Ecological Risk Assessment as Part of
Environmental Analysis Case Study
As discussed above, ecological risk assessment was developed as an analysis
tool to address ecological impacts associated with hazardous waste sites and
contaminated environmental media. This use of the tool continues to be the pri-
mary application of ecological risk assessment, but it has been used in a broader
environmental impact analysis, particularly if contamination is one of the poten-
tial environmental stressors of concern. The tool has been used by the U.S. Army
Corps of Engineers for environmental analysis as part of Environmental Impact
Statements (EISs) in Mobile, Alabama (U.S. Army Corps of Engineers 2002) and
channel dredging programs on the Atlantic Coast.
Ecological risk assessment was also applied in a very controversial EIS
for the reopening of the AJ gold mine in Juneau, Alaska. The mine would