title: PCBs in sediments of the Great Lakes--distribution and trends, homolog and chlorine patterns, and in situ degradation.
abstract: A region-wide data analysis on polychlorinated biphenyls (PCBs) in the sediment of the Great Lakes reveals a total accumulation of approximately 300+/-50 tonnes, representing a >30% reduction from the 1980s. Evidence of in situ degradation of sediment PCB was found, with estimated t(1/2) of 11 and 17 years, at two open water locations in Lake Ontario. The relative abundance of heavy homologs as well as para-chlorines decreases with increasing depth, while the opposite is true for medium and light homologs and ortho-chlorines. In Lake Michigan, the vertical pattern features enrichment of heavier congeners and reduction of ortho-chlorines in deeper sediment layers, opposite to the trend in Lake Ontario. PCBs decrease log-linearly with increasing latitude and longitude. Air deposition of PCBs to lake sediment decreases at about 0.077 ng cm(-2) yr(-1) per degree latitude (N) for the geographic region extending from the Great Lakes to within the Arctic Circle.
authors.affiliation: School of Public Health, University of Illinois at Chicago, USA. anli@uic.edu
authors.forename: An
authors.initials: A
authors.lastname: Li
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Rockne
authors.forename: Neil
authors.initials: N
authors.lastname: Sturchio
authors.forename: Wenlu
authors.initials: W
authors.lastname: Song
authors.forename: Justin C
authors.initials: JC
authors.lastname: Ford
authors.forename: Hua
authors.initials: H
authors.lastname: Wei
mesh_terms: D001673:Biodegradation, Environmental; D002713:Chlorine / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water; D019015:Geologic Sediments / Q000032:analysis*; D006114:Great Lakes Region; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D002713:Chlorine; D011078:Polychlorinated Biphenyls