Quantitative thermodynamic exposure assessment of PCBs available to sandworms (Alitta virens) in activated carbon remediated sediment during ongoing sediment deposition
Citation:
Gidley, P., G. Lotufo, S. Schmidt, P. Mayer, AND Robert M. Burgess. Quantitative thermodynamic exposure assessment of PCBs available to sandworms (Alitta virens) in activated carbon remediated sediment during ongoing sediment deposition. Environmental Science: Processes & Impacts. Royal Society of Chemistry, Cambridge, Uk, 26(5):814-823, (2024). https://doi.org/10.1039/D3EM00405H
Impact/Purpose:
The U.S. EPA is always looking for new tools that improve our ability to determine if the clean-up of a polluted site is working. The present study found that passive sampling of surficial sediment was the most useful for understanding changes in the bioaccumulation of site pollutants by representative animals as a result of cleaning-up a contaminated sediment. Specifically, the application of a very thin coating of silicone as the passive sampler provided for a fast equilibration with the pollutants in the sediment (PCBs). Overall, this type of passive sampling of surficial sediment could be used in existing regulatory frameworks for contaminated sediment site assessment.
Description:
Marine mesoscale studies with sandworms (Alitta virens) were conducted to isolate important processes governing the exposure and bioaccumulation of polychlorinated biphenyls (PCBs) at contaminated sediment sites. Ex situ equilibrium sampling with silicone-coated jars, and in situ passive sampling with low-density polyethylene (LDPE) were used to determine the performance of an activated carbon (AC) amendment remedy applied to the bed sediment. A quantitative thermodynamic exposure assessment (‘QTEA’) was performed, showing that PCB concentrations in polymers at equilibrium with the surficial sediment were suited to measure and assess the remedy effectiveness with regard to PCB bioaccumulation in worms. In practice, monitoring the performance of sediment remedies should utilize a consistent and predictive form of polymeric sampling of the sediment. The present study found that ex situ equilibrium sampling of the surficial sediment was the most useful for understanding changes in bioaccumulation potential as a result of the applied remedy, during bioturbation and ongoing sediment and contaminant influx processes. The ultrathin silicone coatings of the ex situ sampling provided fast equilibration of PCBs between the sediment interstitial water and the polymer, and the multiple coating thicknesses were applied to confirm equilibrium and the absence of surface sorption artifacts. Overall, ex situ equilibrium sampling of surficial sediment could fit into existing frameworks as a robust and cost-effective tool for contaminated sediment site assessment.
URLs/Downloads:
DOI: Quantitative thermodynamic exposure assessment of PCBs available to sandworms (Alitta virens) in activated carbon remediated sediment during ongoing sediment deposition