Anchor QEA, LLC
For the past 30 years, Dr. David Glaser’s work has involved assessment of contaminated sediments and water quality, including remedial investigations, evaluation of remediation options, and modeling of contaminant fate and transport. A particular focus has been the development of contaminant bioaccumulation models to support decision-making. Dr. Glaser has a PhD in ecology, and is a principal scientist at Anchor QEA.
Modeling Bioaccumulation of PFASs in the Aquatic Environment to Support Remedial Decision-Making
Authors: David Glaser, Beth Lamoureux, Deirdre Reidy, Dan Opdyke, Betsy Henry, and John Connolly
The selection of appropriate remedial strategies for contaminants in aquatic environments depends not only on chemical concentrations in abiotic and biotic compartments, but on the properties of the chemicals of concern as well. Chemicals with low partition coefficients are often present in sediments because of ongoing sources and require source control to reduce ecological and human exposure. Chemicals that are persistent, particle-sorptive and bioaccumulative are often legacy contaminants and are often addressed through sediment remediation, as well as source control where appropriate. Relative to traditional legacy contaminants such as polychlorinated biphenyls (PCBs), perfluorooctanesulfonic acid (PFOS), and perfluorooctanoic acid (PFOA) are characterized by relatively low partition coefficients and low bioaccumulation potential in aquatic animals, and therefore source control should be an important consideration in remedial planning. However, PFOS and PFOA are not only released directly into the environment as products of industrial processes, but can also be created in the environment from a multitude of precursors. Such transformations occur in both sediment and fish. Moreover, some precursors exhibit greater partition coefficients than PFOS and PFOA; thus, remedial strategies may depend on the relative concentrations and properties of not only the chemicals of direct concern (often PFOS and PFOA), but of their precursors. A bioaccumulation model was developed to explore these issues. The model embeds a toxicokinetic component within a larger food web calculation that accounts for uptake from both food and water, complex food web structure, and fish migration and movement. Multiple chemicals are modeled, including parent/daughter reactions. A series of illustrative simulations explores how chemical properties can influence remedial decision-making. The impact of fate and transport processes, as they are affected by chemical properties, are also considered.