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(P898) Global accounting of polychlorinated biphenyls in the continental shelf sediments .
Jönsson, Anders1, Gustafsson, Örjan*,, Axelman, Johan1, Sundberg, Henrik1, 1 Stockholm University, Stockholm, Sweden
ABSTRACT- It is believed that over 90% of global sediment burial of organic carbon occur on the continental shelf, representing <10% of the world ocean area. Given the propensity of hydrophobic organic contaminants (HOCs) to associate with organic matter, and the vicinity to population centers, it is plausible that shelf sediments are a repository of significance for global HOC budgets. Thus, the global inventory of polychlorinated biphenyls (PCBs) in continental shelf sediments were modeled based on a congener-specific database of 4213 individual data entries. For each basin, the location of each datum relative to nearest population center was classified as local (< 1 km), regional (1-10 km), and remote (>10 km to shelf break), by importing the data into a comprehensive vector basemap of the world (Digital Chart of the World) within a GIS plateform (Geomedia). The same GIS platform was used to calculate the areal extent of each regime type within the 19 shelf basins. A modified Anderson-Darling statistic demonstrated that the data was best described by a log-normal distribution. Hence, to not disregard the significant presence of censored data, the Maximum Likelihood method was applied to estimate the median and average concentrations for each regime and basin. The remote shelf regimes of the North Atlantic Basin contains about 50% of global shelf sediment PCBs. The mean global inventory of e.g., PCB153 was 1200 ton. This figure is similar to recent estimate of total global emissions and suggests the importance of considering the shelf reservoir and sink in evaluations of global pollution.
Key words: PCBs, global pollution, sediments
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