Using Passive Polyethylene Samplers to Evaluate Chemical Activities Controlling Fluxes and Bioaccumulation of Organic Contaminants in Bed Sediments
Final rept. 19 Jun 2006-31 Jun 2010
MASSACHUSETTS INST OF TECH CAMBRIDGE
Pagination or Media Count:
Many sediment beds are contaminated by hydrophobic organic compounds HOC like PAH and PCB. Evaluating the hazard posed remains a difficult challenge. The HOC presence must be measured in terms that reflect their availability to move to other locations e.g., overlying waters, to receptors e.g., shellfish and fish, and to microorganisms that might facilitate degradation. The objective of this project was to demonstrate the efficacy of using polyethylene PE strips to assess HOC in sediment beds. The method involves insertion of PE strips, pre-loaded with internal standards, across the bed-water interface at sites of concern, leaving the PE to absorb HOC, and then retrieving the samplers and measuring the HOC accumulated in the PE by solvent extraction and gas chromatographic-mass spectrometry. After using the internal standards to extrapolate observed HOC loads to their equilibrium levels, PE-water partition coefficients can be used to calculate contaminant pore water concentrations or chemical activities as a function of depth into the bed. Independent measures of such pore water concentrations showed good correspondence with the PE-inferred results. Moreover, PE-inferred pore water concentrations of PAH at six intertidal field sites were consistent with levels needed to explain PAH tissue burdens in soft-shelled clams living at those locations. Given the relative ease of the PE passive sampling method, these results strongly support the conclusion that future efforts to assess the risks posed by organic contaminants in sediments can be effectively determined using PE passive samplers.
- Inorganic Chemistry
- Organic Chemistry
- Water Pollution and Control