Publications by authors named "Glenn W Johnson"

Article Synopsis
  • - Polychlorinated biphenyls (PCBs) were analyzed in muscle tissue samples from 11 marine mammal species stranded along the UK coast, revealing significant contamination levels, particularly in a killer whale and a Risso's dolphin, with most samples exceeding toxic thresholds.
  • - Many PCB profiles found in the marine mammals did not match typical 'Aroclor' patterns, indicating the presence of congeners resistant to metabolism, while a unique PCB signature was discovered in a sei whale, suggesting atmospheric deposition as a primary source of exposure.
  • - Chiral analysis indicated selective metabolism of certain PCB enantiomers, emphasizing the ongoing health risks posed by PCBs to marine mammals, despite a growing focus on newer pollutants in
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Polychlorinated biphenyls (PCBs) are one of the most widely studied group of persistent organic pollutants (POPs). There are 209 different PCBs, however not all 209 can currently be individually quantified in one analytical run. This means that a subset of PCBs congeners are often determined and reported.

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We collected 27 tree bark samples near Sauget, IL, where 373 000 mt of polychlorinated biphenyls (PCB) was produced between 1936 and 1977 and 10 245 mt was incinerated from 1971 to 1977. Our goal was observe PCB distribution and apparent movement to residential sites, where 24 of 27 samples were collected. Only one of several waste sites was accessible for sampling.

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Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are ubiquitous urban/industrial contaminants found in tree bark, which acts as a long-term passive atmospheric sampler. Twenty seven bark samples (tree age 8–92 years) were collected from residential and industrial areas near Sauget, IL to identify the trends of 2,3,7,8-Cl PCDD & PCDF congener distributions, toxic equivalents (TEQ), and PCDD & PCDF homologue distributions. The Sauget area is heavily industrialized, with a long history of chlorine production, and is the largest single contributor to air pollution exposure risk in St.

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PCB signatures can be used for source identification, exposure studies, age dating and bio-monitoring. This study uses comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS) to produce a PCB signature comprised of over 80 PCBs for individual Leach's storm petrels (Oceanodroma leucorhoa). The Leach's storm petrel is a relatively small, elusive, understudied pelagic bird, which only returns to remote islands under darkness during the breeding season.

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Exposure to polychlorinated biphenyls (PCBs) is high among the Inuit resulting from ingestion of contaminated wild "country" foods. These contaminants originate in urban/industrial areas and reach the Arctic by long-range atmospheric transport. Ingested PCBs eventually equilibrate into various body components, including feces, which become an indication of body burden.

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Monsanto produced two distinct variants of Aroclor 1254. The late-production variant resulted from a change in Monsanto's manufacturing process in the early 1970s. Previous literature had reported that the late-production variant was produced from 1974 to 1976, but subsequent work has identified a sample known to be obtained in 1972.

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Tree bark samples were collected to identify the relative amounts and congener profiles of atmospheric polychlorinated biphenyls dissolved into bark lipids from the gas phase in Anniston, Alabama, USA, where PCBs were manufactured from the 1920s until 1971. The area is heavily contaminated with PCBs: At least 4550 metric tons (mt) of PCB and 14000 mt of PCB distillation residue, known as Montar, remain buried in two landfills near the plant site. A minimum of 20.

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This paper reports on extensive polychlorinated biphenyl (PCB) dechlorination measured in Lake Hartwell (Pickens County, SC) sediments. Vertical sediment cores were collected from 18 locations in Lake Hartwell (Pickens County, SC) and analyzed in 5-cm increments for PCB congeners. The preferential loss of meta and para chlorines with sediment depth demonstrated that PCBs in the sediments underwent reductive dechlorination after burial.

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Under anaerobic conditions, such as those typically found in buried sediments, the primary metabolic pathway for polychlorinated biphenyls (PCBs) is reductive dechlorination in which chlorine removal and substitution with hydrogen by bacteria result in a reduced organic compound with fewer chlorines. Vertical sediment cores were collected from Lake Hartwell (Pickens County, SC) and analyzed in 5-cm intervals for 107 PCB congeners in a total of more than 280 samples from 18 sediment cores and surface samples. This paper reports on extensive PCB dechlorination measured in Lake Hartwell sediments and the characterization of dechlorination end-member (EM) patterns using chemical forensic methods.

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The major determinants of human polychlorinated biphenyl (PCB) body burden include the source and route of exposure and the toxicokinetic processes occurring after uptake. However, the relative importance of each factor for individual subjects cannot currently be determined. The present study characterizes levels and patterns of PCB congeners in a large cohort of adult Akwesasne Mohawks with historical PCB exposure.

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