title: Record of PCB congeners, sorbents and potential toxicity in core samples in Indiana Harbor and Ship Canal.
abstract: Indiana Harbor and Ship Canal (IHSC) is an active navigational system that serves a heavily industrial area of southern Lake Michigan. We have determined the amount of polychlorinated biphenyls (PCBs), congener distributions, sorbent types and potential for dioxin-like PCB toxicity from two IHSC sediment cores. Vertical distributions of ΣPCBs (sum of 161 individual or coeluting congeners) ranged from 410 to 91000 and 1800 to 41000 ng g(-1) dry weight (d.w.) for cores 1 and 2, respectively. Core 1 showed its highest accumulation rate for the year ∼1979 and exhibits a strong Aroclor 1248 signal in sediments accumulating over the last 60 years. It appears that from the late 1930s until the beginning of the 1980s there was a large and constant input of PCBs into this system. This pattern differs from lake cores from the Great Lakes region which commonly exhibit a rapid increase, a peak, followed by a sharp decrease in the PCB accumulation rates. Core 2 also has a strong Aroclor 1248 signal in the top layers, but deeper layers show evidence of mixtures of Aroclors and/or weathering processes. High levels of black carbon as a fraction of total organic carbon were found in both cores (median ∼30%), which reflect the long history of local combustion sources. No strong relationship was found between ΣPCB concentration and sorbents. Both cores contain dioxin-like PCBs that are highest in concentration below the surface. The high levels of PCBs in the deep sediments are of concern because of plans to dredge this system.
authors: Department of Civil & Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242, USA.
authors: Andres
authors: A
authors: Martinez
authors: Keri C
authors: KC
authors: Hornbuckle
mesh_terms: D001140:Aroclors / Q000032:analysis; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry; D049673:History, 20th Century; D049674:History, 21st Century; D007196:Indiana; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000266:history / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000266:history / Q000633:toxicity
chemical_list: D001140:Aroclors; D014874:Water Pollutants, Chemical; C028617:aroclor 1248; D011078:Polychlorinated Biphenyls