Pathway and products of PCB dechlorination in contaminated sediments: Reduction of health hazards and enhancement of microbial activities

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:491078

Sokol, R C; Bethoney, C M; Rhee, G Y ^[1]

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1. State Univ. of New York, Albany, NY (United States). School of Public Health

Reductive dechlorination of polychlorinated biphenyls primarily removes chlorines (Cls) from the meta and para positions although ortho dechlorination has also been reported. This preferential removal is determined by the pattern of Cl substitution. Thus, the final products may not only be orth-substituted congeners. In fact, certain congeners such as 2,4{prime}-, 2,5,2{prime}-, 2,4,4{prime}, 2,4,2{prime},5{prime}- and 2,4,2{prime}4{prime}-chlorobiphenyls accumulated at high concentrations in both the laboratory and natural sediments in the Hudson and St. Lawrence Rivers. Many of these accumulating congeners are known to be neurotoxic by reducing cellular dopamine content. Therefore, although in-situ dechlorination may reduce the overall degree of chlorination, it is important to consider the health implications of accumulating products. Dechlorination competence varies with sediment microorganisms from different sites, resulting in the accumulation of dissimilar products. Microorganisms from the General Motors site in the St. Lawrence River removed a higher proportion of para Cls relative to meta whereas those organisms at the Reynolds and ALCOA sites removed a higher proportion of meta Cls. Sediment amendments with H{sub 2} or biphenyl also resulted in the accumulation of different products. These results suggest that it may be possible to alter the final products through artificial manipulations. The authors have identified several conditions which are critical for dechlorination.

• OSTI ID: 491078
• Report Number(s): CONF-9406250--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BENCH-SCALE EXPERIMENTS
BIODEGRADATION
DETOXIFICATION
ENVIRONMENTAL EXPOSURE PATHWAY
FIELD TESTS
HUDSON RIVER
POLYCHLORINATED BIPHENYLS
REMEDIAL ACTION
SEDIMENTS
ST LAWRENCE RIVER