Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)
Citable URI
https://hdl.handle.net/1912/7305DOI
10.1575/1912/7305Keyword
Marine pollution; Chemical oceanographyAbstract
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.
Description
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
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Suggested Citation
Thesis: 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/1912/7305Related items
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