Biological Activity Associated With Noncoplanar Polychlorinated Biphenyls After Microbial Dechlorination of Aroclor 1242® and Aroclor 1254®

Ganey, Patricia E.; Quensen, John F.; Mousa,; Boyd, Steven A.; Wagner, Verena; Fischer, Lawrence J.

doi:10.1897/1551-5028(2000)019<1311:baawnp>2.3.co;2

Cited by 2 publications

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“…The inability of microbial dechlorination to modify activity of commercial PCB mixtures on insulin secretion, neutrophil activation and splenocyte proliferation has been attributed to the presence of ortho-substituted PCB congeners with three or fewer chlorines (Ganey et al, 2000;Smithwick et al, 2004). Consistent with the latter report, structure-activity studies in our laboratory show that ortho-substituted di-and trichlorobiphenyls elicited increased uterine contraction frequencies of the magnitude similar to that observed with HR1260 (in preparation).…”

Section: Discussionsupporting

confidence: 80%

Stimulatory effects of a microbially dechlorinated polychlorinated biphenyl (PCB) mixture on rat uterine contraction in vitro

Tsuneta¹,

Loch‐Caruso²,

Quensen³

et al. 2008

Environmental Research

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Microbially mediated reductive dechlorination has been advocated as the first part of a two-stage (anaerobic/aerobic) biotreatment process for polychlorinated biphenyls (PCBs) in sediments, and is generally viewed as a detoxication process. However, previous studies suggest that microbial dechlorination increases ability to stimulate uterine contractions compared with the original PCB mixtures. Here, we investigate the composition and uterotonic activity of the commercial PCB mixture Aroclor 1260 before and after incubation with microorganisms eluted from PCBcontaminated sediment of the Hudson River. Incubation with microorganisms resulted in a partially dechlorinated mixture (HR1260) dominated by ortho-substituted PCBs with four or fewer chlorines per biphenyl. Aroclor 1260 that had not been incubated with microorganisms had no significant effect on contraction frequency of rat uterine strips (gestation day 10) in vitro, whereas HR1260 dramatically increased contraction frequency to 718 ± 134% of the basal rate at a total PCB concentration of 70 μM (p<0.05). The microbial dechlorination increased 2,2′,4,4′-tetrachlorobiphenyl and one or more of four congeners that co-eluted during chromatography (2,3,3′, 5-tetrachlorobiphenyl, 2,3′,4,5-tetrachlorobiphenyl, 2,2′,4,4′,6-pentachlorobiphenyl and 2,2′,4,5′,6-pentachlorobiphenyl) to 24 and 8 mol %, respectively. However, the uterotonic activities of the latter congeners were modest when evaluated either solely or in a reconstituted mixture and could not fully account for the uterotonic activity of HR1260. Nonetheless, the relative abundance of congeners with three or fewer chlorines increased to 14 mol % as a group in HR1260, suggesting that these congeners collectively contribute to the uterotonic activity even though the abundance of any one congener in this group was less than 5 mol %.

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Section: Discussionsupporting

confidence: 80%

Stimulatory effects of a microbially dechlorinated polychlorinated biphenyl (PCB) mixture on rat uterine contraction in vitro

Tsuneta¹,

Loch‐Caruso²,

Quensen³

et al. 2008

Environmental Research

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“…For certain POPs, such as PCBs and selected organochlorine (OC) pesticides, primary releases in northern industrialized countries have effectively diminished, with atmospheric concentrations largely accounted for by continued (re)volatilization from contemporary reservoirs such as soil, vegetation, and water (e.g., refs 13-16). Given the gradual depleting processes for these persistent compounds through reactions with OH radical (17), hydrolysis (18), microbial action (19), and loss to the ocean floor (20)(21), then, assuming no further primary releases, atmospheric concentrations should be expected to decline; albeit, gradually over many years. Evidence of this is now apparent from several temperate studies, which have revealed reductions in atmospheric concentrations of PCBs (22,23).…”

Section: Introductionmentioning

confidence: 99%

Are PCBs in the Canadian Arctic Atmosphere Declining? Evidence from 5 Years of Monitoring

Hung

Halsall

Blanchard

et al. 2001

Environ. Sci. Technol.

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A long-term database of weekly air concentrations was examined to establish temporal trends of PCBs in the Arctic atmosphere. Several methods were employed to reduce the intra-annual variability allowing the elucidation of longterm trends for a selection of congeners at Alert located in the Canadian Arctic. These methods included temperature normalization (TN), multiple linear regression (MLR), and digital filtration (DF). Estimation of the slope (m) resulting from the linear regression between the natural logarithm of the partial pressure in air versus reciprocal temperature (In P = m/T + b), required for TN and MLR, proved difficult due to the poor correlation with temperature experienced forthe majority of congeners. Values of m were considerably lower than those obtained from temperate studies, implying that regional air-surface exchange plays a minor role in supporting the observed air concentrations in the Arctic. The lighter congeners generally showed very low slopes, and some even showed positive correlation with 1/T. This might be a result of their relatively fast reaction rates with OH radicals following the onset of 24-h sunlight in spring. Use of DF (in combination with TN and MLR) revealed declining trends for several of the lower chlorinated congeners in the high Arctic atmosphere, with estimated first-order half-lives, t1/2, ranging from approximately 3 to 20 yr. Declining trends of the lower congeners probably reflect falling levels in source regions, as a result of long-range transport to this Arctic site. There were no apparent trends for the higher chlorinated congeners (penta-substituted and above), exceptfor PCB 180, in marked contrast to temperate studies, indicating a lag time for decline between the Arctic and source regions.

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Biological Activity Associated With Noncoplanar Polychlorinated Biphenyls After Microbial Dechlorination of Aroclor 1242® and Aroclor 1254®

Cited by 2 publications

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Stimulatory effects of a microbially dechlorinated polychlorinated biphenyl (PCB) mixture on rat uterine contraction in vitro

Stimulatory effects of a microbially dechlorinated polychlorinated biphenyl (PCB) mixture on rat uterine contraction in vitro

Are PCBs in the Canadian Arctic Atmosphere Declining? Evidence from 5 Years of Monitoring

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