CEE Seminar: Biogeochemical Controls on Mercury Methylation and Implications for in Situ Sediment Management Strategies at Berry's Creek Study Area, New Jersey
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April 3, 2018 - 12:00pm to 1:00pm
Dimitri Vlassopoulos, Anchor QEA LLC, Portland, Oregon
Environmental risk at mercury (Hg) contaminated sediment sites derives mainly from methylmercury (MeHg) exposure and bioaccumulation. MeHg levels in sediments and porewater reflect a complex, dynamic and incompletely understood interplay between physical, geochemical and biological processes, and generally do not correlate well with total sediment Hg concentrations. MeHg is produced mainly by certain sulfate-reducing and iron-reducing microorganisms and can be demethylated via both abiotic and biotic pathways. In situ remediation approaches for mercury contaminated soils and sediments therefore have targeted (1) reducing the bioavailability of Hg to methylating microorganisms and/or (2) manipulating biogeochemical conditions to limit microbial activity related to net MeHg production. As part of extensive CERCLA site investigations conducted at the Berrys Creek Study Area (BCSA) in New Jersey, a conceptual biogeochemical framework integrating multiple lines of evidence and accounting for key aspects of Hg partitioning and MeHg production and partitioning was developed.....