Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)
Tcaciuc, Alexandra P.
MetadataShow full item record
Hydrophobic organic chemicals (HOCs) are a class of environmental contaminants responsible for numerous acute and chronic health effects in humans and wildlife. This thesis illustrates three applications of polyethylene (PE) passive sampling, which enhance our toolbox for estimating environmental hazards associated with HOCs. First, we present a methodology that can be used to estimate the bioaccumulation potential of numerous organic chemicals based on passive sampling and comprehensive two dimensional gas chromatography (GC × GC). Using GC × GC retention times, we show that lipid-water and samplerwater partition coefficients can be estimated within a factor of 2 and 3, respectively. The method was then applied to estimate body burdens of various HOCs in benthic organisms from GC × GC analysis of PE equilibrated with contaminated sediment. Empirical observations of accumulation in the Nereis virens polychaete were in good agreement with PE-based predictions for PCBs, but were lower by at least an order of magnitude for other classes of HOCs (such as PAHs) presumably due to metabolism. Second, we applied the same methodology to a set of contaminated sediments and estimated the cumulative baseline toxicity associated with environmental mixtures of HOCs. The predictions were compared against empirical measurements of baseline toxicity using the water flea Daphnia magna. The estimated total body burdens of HOCs were in good agreement with measured toxicity, with toxicity occurring at body burdens larger than 30 mg/glipid. In contrast, the toxicity estimated based on priority pollutants severely underestimated the observed toxicity, emphasizing the importance of cumulative effects. Lastly, to advance our understanding of the processes that affect passive sampling results in situ (when they are operating away from equilibrium), a mathematical model was developed for reactive chemicals transferring between PE and sediment beds. The reaction diffusion model was used to infer in situ degradation rates of dichlorodiphenyltrichloroethane (DDT), which in the sediments of a freshwater lake were found to be between 0.09 and 0.9 d-1. A second mathematical model describing the kinetics of exchange between passive samplers and water was also developed, which can be used in both field (infinite baths) and laboratory (finite baths) conditions.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute Of Technology and the Woods Hole Oceanographic Institution June 2015
Suggested CitationThesis: Tcaciuc, Alexandra P., "Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)", 2015-06, DOI:10.1575/1912/7305, https://hdl.handle.net/1912/7305
Showing items related by title, author, creator and subject.
Biological-physical interactions on Georges Bank : plankton transport and population dynamics of the ocean quahog, Arctica islandica Lewis, Craig V. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-06)Advective losses of bank water during winter because of strong wind forcing were hypothesized to be a significant factor limiting recruitment of Georges Bank cormnunities. This hypothesis was examined using biological-physical ...
Montgomery, Raymond B. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1938-08)Except for the presence in most localities of a shallow homogeneous surface layer and of a relatively homogeneous and deeper bottom layer, the oceans of the temperate and tropical regions are stratified and vertically ...
Ogden, Kelly A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2017-02)Internal hydraulic jumps in flows with upstream shear are investigated numerically and theoretically. The role of upstream shear has not previously been thoroughly investigated, although it is important in many oceanographic ...