| ||BASIS #||2309TZ 26|
| ||Title||Hazard Assessment of Contaminated Sites at Beltsville Agricultural Research Center|
| ||Project Description||
The Beltsville Agriculture Research Center (BARC) was declared a Superfund site under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in the 1980's due to historical pollution of persistent contaminants including metals and some organic compounds. Several environmental assessments have been conducted since then and many of the forested wetlands located on BARC property have been identified as areas of concern.
have been of concern under these assessments because they are important parts
of the communities they inhabit and are frequent residents and breeders in
affected wetlands. In
the BARC Facility-wide Screening-Level Ecological Risk Assessment (SERA) and
Step 3a ERA reports (ENTECH Inc., 2001 and 2002), exposure pathways for
amphibians were considered in conjunction with fish as aquatic receptors.
In the subsequent Baseline Ecological Risk Assessment (BERA),
amphibians were considered separately from fish because amphibians may be at
increased risk to effects of environmental stressors including site-related
least nine species of anurans (frogs and toads) and several more salamanders
inhabit BARC or adjacent lands.
Many potential exposure pathways link these amphibians to contaminants
of concern (COCs). These include contact with water borne or dissolved
contaminants in any of the life stages, direct dermal or respiratory contact
while on land as juveniles or adults, ingestion of contaminant-bearing
detritus or insects as larval or adults, or dermal absorption from
contaminated sediments as larvae or hibernating adults.
Effects from these contaminants in laboratory exposures generally occur
in the ppm range for median lethal concentrations (LC50s)
and even the ppb range for measurable sublethal effects.
Given the range of possible scenarios and that the source of
contamination was more historical rather than current, we believe that the
route of exposure of greatest concern comes from contact with sediments or
over-lying water that contain persistent contaminants such as metals and
certain organic compounds.
Because sediments contain much higher concentrations of persistent
contaminants (by 1-3 orders of magnitude) than water, it can be surmised that
sediments may pose greater threats.
| ||Keywords||Sediment toxicity, amphibians,
Superfund, risk assessment, organochlorines, metals, Rana,
| ||Principal Investigator||Don Sparling, USGS Patuxent Wildlife Research Center: Don_Sparling@usgs.gov|