New Passive Samples (PEDs) for Assessing Bioaccumulation of Organic Substances from Contaminated Sediments and Overlying Seawater

Lead Pi: Philip Gschwend · 3/2002 - 2/2003

Project Personnel:

Project number: 2002-RC-82

Objectives:1. To establish the utility of new passive samplers called polythylene devices (PEDs) for assessing the chemical activities/fugacities of hydrophobic organic compounds like PAHs, PCBs, and PCDDs in the environment.2. To demonstrate the effectiveness of the PEDs in a particular field setting, Boston Harbor, where HOCs are present and need to be assessed under field conditions.Methodology:1. Laboratory incubations of PEDs, with defined solutions (temperatures, salinities, HOC concentrations) will be used to determine polyethylene water partition coefficients for representative PAHs and PCBs. 2. Laboratory incubations of PEDs, doped with deuterated PAHs, will be studied to establish the utility of using the loss rates observed for these deuterated “internal standards” for assessing the kinetics of PED-water exchange under particular conditions (e.g. hot v. cold, turbulent v. quiescent, clean surface v. fouled). 3. Field deployments of PEDs will be made and the resultant HOC/Deuterated HOC loads analyzed afterwards to demonstrate the effectiveness of this new passive sampling methodology in real world conditions.Rationale:In order to assess the hazard posed by contaminated sediments, we need to be able to quantify the likelihood of bioaccumulation of the pollutants. This requires knowledge of the pollutant chemical activity/fugacity in both the bed and the water column. Improved methods for measuring water column activities/fugacities (not concentrations) of very low solubility HOCs are needed to permit accurate predictions of bioaccumulation of these contaminants.