Department of Environmental Sciences
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Seminar Abstracts
Environmental Sciences Seminar Abstract            

  USE OF CHEMICAL FORM AND ECOTOXICITY INFORMATION IN METALS CONTAMINATED SITE REMEDY SELECTION
Mark Sprenger
U.S. ENVIRONMENTAL PROTECTION AGENCY

It has long been known from environmental chemistry and toxicology that the chemical form of metals has a dramatic effect on their fate, transport and toxicity in the environment. The differences can be dramatic, for example hexavalent chromium can be very mobile in the environment and is toxic, whereas trivalent chromium is much less mobile and has very reduced toxicity and is a micro nutrient. Within Superfund there is a requirement that the selected remedy for a site is "protective" of human health and the environment. Worst case assumptions may be made regarding the chemical form of metals contamination due to concerns over chemical form transformations or to ensure the protectiveness of the remedy selected. However, there are costs associated with these assumptions; these costs include not only larger monetary expenditures but potentially: loss of landfill capacity; unnecessary habitat destruction from soil or sediment removal; and unnecessary "harvesting" of top soil to replace removed soils. These "non-monetary" costs are often in conflict with the concepts of sustainable remediation. Two examples will be presented where knowledge of the environmental chemistry and ecotoxicity were used to in one case limit the remediation of a site and the associated stream and floodplain; in the other, soil amendment techniques were used to alter the contaminant availability, and ecotoxicity data was used to demonstrate remediation success.


Last updated: 09/04/2011