Sorption of organic compounds to microbial extracellular polymers: Potential vector for bioaccumulation of sediment-associated contaminants
- Univ. of South Carolina, Columbia, SC (United States)
Microbial extracellular polymeric substances (EPS) in the form of organic carbon coatings are ubiquitous features of marine surficial sediments and suspended particulate matter. Consisting primarily of polysaccharides, EPS are produced by bacteria for adhesion to substrata, to bind essential nutrients, and to protect bacterial cells from exogenous stressors, including toxic trace metals. EPS particulate coatings are easily digested by marine particle-ingesting invertebrates. Additionally, these organisms directly assimilate dissolved organic material and trace metals adsorbed to EPS-coated particulate. The capacity of EPS-coated particulate matter to serve as a vector for bioaccumulation of sediment-associated contaminants has not been addressed. As a step, the authors measured adsorption of selected organic contaminants by EPS-coated hydrated silica particles (mean diameter = 30 {micro}m). Radio-labeled organic contaminants, including benzo(a)pyrene, hexachlorobiphenyl, and the pesticides azinphosmethyl and chlorpyrifos were associated with coated particles in seawater under constant pH, salinity, temperature, and Eh. Mixtures were incubated until equilibrium was approximated, at which point partitioning between seawater and particulate was determined for each particulate/contaminant combination. The organic compounds exhibited a range of log K{sub ow} from 2.6 (azinphosmethyl) to 6.7 (hexachlorobiphenyl), which allowed for quantification of the relationship between partitioning and contaminant hydrophobicity. Effects of differential EPS composition were evaluated by measuring binding affinity of hexachlorobiphenyl particles coated with EPS obtained from three bacterial species which produce EPS with unique compositional attributes: Azotobacter vinelandii, Leuconostoc mesenteroides, and Pseudomonas atlantica.
- OSTI ID:
- 398193
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9649%%401
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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