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Evaluating polymer-based sampling for predicting the bioaccumulation of hydrophobic organic contaminants by higher trophic level organisms
Citation:
Schmidt, S. AND R. Burgess. Evaluating polymer-based sampling for predicting the bioaccumulation of hydrophobic organic contaminants by higher trophic level organisms. Society of Environmental Toxicology and Chemistry (SETAC) North America 39th Annual Meeting, Sacramento, CA, November 04 - 08, 2018.
Impact/Purpose:
A significant concern about pollution in the environment is that it accumulates in the food we eat. For example, in the aquatic environment, we know fish and shellfish can accumulate pollutants like PCBs. If we eat the contaminated fish or shellfish, the pollutants may be passed to us and cause harmful effects. Determining if fish and shellfish are contaminated is logistically challenging and expensive because it involves capturing lots of animals and performing expensive chemical analyses. We are investigating the ability of a recently developed technology called passive sampling to predict bioaccumulation by fish and shellfish that humans may consume as food. If this research is successful, we will have a new tool for estimating the threat to humans represented by contaminated fish and shellfish.
Description:
Recent research has shown that bioaccumulation of hydrophobic organic compounds by benthic and sessile marine organisms can be accurately predicted by partitioning-based sampling (within a factor of 10). In these lower trophic level organisms, bioaccumulation can thus be explained by equilibrium partitioning. Now, research is needed to assess the ability of partitioning-based sampling to estimate bioaccumulation by pelagic and mobile organisms (i.e., by higher trophic level organisms). The limited available research on the topic states that processes beyond simple equilibrium partitioning need to be taken into consideration to accurately estimate bioaccumulation by these organisms. Generally, two partitioning-based (passive) sampling approaches are used: (1) the ex situ equilibrium sampling approach fully equilibrates a thin polymer with sediment during tumbling in the laboratory and (2) the in situ pre-equilibrium sampling approach places a thicker polymer within the bulk water or sediment on site and then infers equilibrium concentrations through the use of performance reference compounds (PRCs). As noted above, the equilibrium polymer concentrations can be used as a surrogate predictor of bioaccumulation in lower trophic level organisms. In addition, freely dissolved concentrations (Cfree) can be determined as the ratio of the equilibrium concentrations in the polymer and polymer to water partition ratios. The current study reviews existing literature linking partitioning-based sampling data and bioaccumulation by higher trophic level shellfish and fish. The equilibrium polymer concentrations and Cfree determined by partitioning-based sampling are incorporated into bioaccumulation models to predict wet weight concentrations, lipid-normalized concentrations and chemical activity in higher trophic level organisms. Ideally, this research will provide an assessment of the ability to predict bioaccumulation by higher trophic level organisms using partitioning-based sampling approaches. If successful, this research will serve as a tool for regulatory agencies (e.g., U.S. EPA) to assess risk associated with contaminated sediments in terms of their potential to contaminate commercially and recreationally important shellfish and fish.