This is the first part of a study that evaluates the influence of nonpoint-source contaminants on the sediment quality of five streams within the metropolitan Kansas City area, central United States. Surficial sediment was collected in 2003 from 29 sites along five streams with watersheds that extend from the core of the metropolitan area to its development fringe. Sediment was analyzed for 16 ...

PCBs are a group of synthetic organic chemicals that contain 209 possible individual chlorinated biphenyl compounds. These chemically related compounds are called congeners and vary in their physical and chemical properties and toxicity. There are no known natural sources of PCBs. Although banned in the United States from further production in 1979, PCBs are distributed widely in the environmen...

Parallel, chronic (24 months) multidose bioassays of the PCB (polychlorinated biphenyls) Aroclors 1016, 1242, 1254, and 1260 in male and female Sprague-Dawley rats showed sex/Aroclor-dependent increases in hepatic tumors and decreases in extrahepatic tumors. To elucidate the PCB mode of action (MOA) involved, levels of a number of hypothesized mediators were measured in liver specimens collecte...

Polychlorinated biphenyls (PCBs), which have been commercially manufactured since 1929, are complex mixtures of many congeners and several homologues. They have been used in a variety of industrial and non-industrial applications which has allowed large quantities to be released into the workplace and environment1-6. Based on a 198 1 estimate, as many as 17 million pounds of PCBs were entering ...

Aroclor 1254 is a widely studied commercial polychlorinated biphenyl (PCB) mixture which, by definition, contains 54% chlorine by weight. Recent reports indicate substantial differences in the congener composition among Aroclor lots and hence their biologic effects. We designed the current study to compare the effects of two lots of Aroclor 1254 (lots 6024 and 124-191). We analyzed these two lo...

It has taken three decades from the first report of microbial polychlorinated biphenyl (PCB) dechlorination to identify even one of the enzymes responsible. By combining conventional techniques with their own ingenuity, the latest technologies, and a bit of luck, Wang et al., in PNAS, have identified not one, but three distinct enzymes that can reductively dechlorinate PCBs (1). This finding is...

detected in these blank determinations that we were not certain whether it came from the Soluene or other sources. You may note that the blood of control rats which was analyzed with the use of Soluene did not contain detectable amounts of asbestos and zero fibers per gram was reported. We have since repeated this work (as yet unpublished) in an experiment in which asbestos was fed to rats and ...

Polychlorinated biphenyls (PCBs) as environmental contaminants often cannot be adequately described by reference to Aroclors or to total PCBs. Although there are 209 possible PCB configurations (congeners), perhaps half that number account for nearly all of the environmental contamination attributable to PCBs. Still fewer congeners are both prevalent and either demonstrably or potentially toxic...