PARENT SESSION
PT8 - Chemistry & Toxicity of Sediments
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P671) Use of the Sediment Quality Triad to Evaluate the Effects of PAH in a New England Pond.
Rothrock, Julie*,1, Anderson, Paul1, Bollinger, Mike2, Patarcity, Jane2, 1 AMEC Earth and Environmental, Westford, MA, USA2 Beazer East, Inc., Pittsburgh, PA, USA
ABSTRACT- The Hocomonco Pond Superfund Site in Westborough, Massachusetts was dredged in the mid-1990s to remove sediments containing polycyclic aromatic hydrocarbons (PAH) from former wood-treating operations. It was recently found that as the result of continued discharge of dissolved PAH from groundwater, remediated sediments in a small portion of the pond had elevated concentrations of PAH. Groundwater restoration at the Site has been demonstrated to be technically impracticable due to the presence of residual and free-phase dense nonaqueous phase liquids (DNAPL) in the Site aquifer. The U.S. Environmental Protection Agency and the Massachusetts Department of Environmental Protection approved a Technical Impracticability waiver for the Site and requested long-term monitoring of groundwater and sediment. As part of the monitoring activities, baseline biological sediment data were gathered using the sediment quality triad approach. Data were gathered from three impacted locations and two reference locations in the pond. Colocated sediment samples were analyzed for PAH, total organic carbon, grain size, and percent solids; ten-day Hyalella azteca and Chironomus tentans survival and growth; and benthic macroinvertebrate community abundance and diversity. Results for impacted locations were compared to those from reference locations. In addition, all results were compared to freshwater sediment quality guidelines (SQGs), including threshold effect and probable effect concentrations, to evaluate the site-specific predictive ability of these SQGs for PAH-containing sediments. These results and their implications for the evaluation and application of SQGs are discussed.
Key words: sediment, invertebrates, toxicity tests, sediment quality guidelines