PT01 Assessing Contaminated Soil Sites
Exhibit Hall
8:00 AM - Tuesday, 11 November 2003
(PT005) Application of ecological risk assessment to support habitat restoration.
Mayhew, D.1, Boltz, J.1, Derrick, P.1, Papageorgis, C.1, Walker, A.2, 1 EA Engineering, Science, and Technology, Inc., Sparks, Maryland, USA2 U.S. Army Corps of Engineers, Baltimore District, Baltimore, Maryland, USA
ABSTRACT- Terrestrial ecological risk assessments were carried out on Heritage and Kingman Islands in the Anacostia River in the District of Columbia. The islands were originally created from dredged material in the early part of the twentieth century. The risk assessments were part of a series of investigations undertaken by the Baltimore District U.S. Army Corps of Engineers to support the District of Columbia′s Preferred Master Plan for restoration of the islands for human and wildlife use. Surface soil samples were collected from representative habitats and analyzed for TAL/TCL chemicals. Mean soil concentrations were screened against benchmarks from EPA Eco-SSL, Oak Ridge, and Dutch sources. A number of metals, particularly lead, vanadium, and aluminum, exceeded benchmarks and were considered potential risks to plants and/or invertebrates and wildlife. The metals exceeding benchmarks, as well as the bioaccumulative pesticides/PCBs, were included in a terrestrial food-web exposure model. This model evaluated risks from surface soil to American robin, cottontail, red-tailed hawk, and red fox. Risks from several metals and DDT were projected for the robin and cottontail. Background comparisons removed several metals as risk drivers. The remaining analytes were evaluated on a station-by- station basis, and, based on LOAEL HQs greater than 1.0, zinc and DDT were found to pose risk at one or two isolated locations. Risk from lead was more widespread, particularly on Kingman Island. This information, along with results from a parallel human health risk assessment, is being incorporated into the District of Columbia′s planning process for restoration of the island habitats.
Key words: habitat restoration, ecological risk assessment, food-web exposure model, background comparisons