title: Pan-arctic river fluxes of polychlorinated biphenyls.
abstract: Observations of polychlorinated biphenyls (PCB) concentrations in fluvial surface sediments near the mouths of the six Great Arctic Rivers (GARs; Ob, Yenisey, Lena, Indigirka, Kolyma, and Mackenzie) were combined with annual dissolved organic carbon (DOC) and particulate organic carbon (POC) loadings and hydraulic discharge to estimate the pan-Arctic river flux of PCBs. The highest total-phase fluxes of ∑(13)PCB were found for the Ob River, with 184 kg/yr and the smallest for the Indigirka River with 3.9 kg/yr. Consistent with a continent-scale trend among the Eurasian GARs of increasing POC concentrations eastward, which is extending to the North American Mackenzie River, a general shift in the estimated PCB partitioning from dissolved to particle-associated flux was found toward the east. Pentachlorinated and hexachlorinated PCBs constituted the majority (>70%) of the total PCB fluxes in the Eurasian Rivers. In contrast, trichlorinated and tetrachlorinated congeners were the most abundant in the Mackenzie (≈ 75%). The total ∑(13)PCB fluxes from the pan-Arctic rivers are here estimated to be ∼0.4 tonne/yr. This is geochemically consistent with the inventory of total PCBs in the Polar Mixed Layer of the entire Arctic Ocean (0.39 tonne) and about a factor 2 less than two new estimates of the PCB settling export to Arctic subsurface waters. Hence, the yearly Great Arctic River PCB fluxes only represent 0.001% of the historical PCB emission into the global environment. To our knowledge, this is the first estimate of circum-Arctic river flux of any organic pollutant based on a comprehensive investigation of the pollutants in several rivers and it contributes toward a more complete understanding of large-scale contaminant cycling in the Arctic.
authors.affiliation: Department of Applied Environmental Science (ITM), Stockholm University , 106 91 Stockholm, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carrizo
authors.forename: Örjan
authors.initials: Ö
authors.lastname: Gustafsson
mesh_terms: D001110:Arctic Regions; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry; D009792:Oceans and Seas; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011078:Polychlorinated Biphenyls