| Summary: | Chlorinated biphenyl compounds have become ubiquitous components of the global environment. They were first detected in species of Swedish wildlife (1, 2, 3) and were subsequently found in seals from the North Atlantic (4), in a bird of prey in Great Britain (5), in fish and birds from the Netherlands (6), and in both terrestrial and marine species of wildlife in western North America (7). In the Arctic they are present in the polar bears (Thalarctos maritimus) of Hudson Bay (8) and in fresh-water fish of tundra lakes that receive no pollutants save those that are present in the fallout from the atmosphere (9). In the Southern Hemisphere, they were found in all bird species analyzed that inhabit waters north of the Antarctic Convergence but could not be detected in a number of samples of wildlife resident in Antarctica south of the Convergence (10). In this paper some of the available residue data are summarized within the framework of a preliminary formulation of a mass balance equation for the global distribution of polychlorinated biphenyls. Commercial manufacture of PCBs was begun in the United States in 1929 (11), and environmental input may be assumed to have begun at that time. Current levels of PCBs in major sinks, such as the oceans, are evidently a function of many parameters, including the proportion of the total amount of PCBs produced over the past forty years that has so far entered the environment, pathways of dissemination, rates of degradation-to other compounds, partition coefficients between water and lipid fractions of organisms
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