Concentrations, Accumulations, and Inventories of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Sediments of the Great Lakes

• Published in: Environmental science & technology 1997-10, Vol.31 (10), p.2903-2909
• Main Authors: Pearson, Roger F, Swackhamer, Deborah L, Eisenreich, Steven J, Long, David T
• Format: Article
• Language: English
• Subjects: Applied sciences; DIBENZOFURANE; DIBENZOFURANOS; DIBENZOFURANS; DIOXINAS; DIOXINE; DIOXINS; Exact sciences and technology; Freshwater; Pollution; Pollution sources. Measurement results; Soil and sediments pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9701016

The chronology of PCDD/F accumulation was determined in sediment cores from Lakes Superior, Michigan, and Ontario and two small “control” lakes. Accumulation rates began increasing about 1940, increased to maxima at 1970 ± 10 yr, and then declined to the present rates that are 30−70% of the maxima. The observed accumulations ranged from 90% of their current PCDD/F inputs from subregional atmospheric (air parcels having higher concentrations of PCDD/F than remote air due to local sources) and/or non-atmospheric sources. We also compared the sedimentary accumulations to estimates of atmospheric deposition. The PCDD/F accumulation rates in the control lakes were similar to atmospheric deposition of PCDD/Fs from remote air in the Great Lakes basin. Atmospheric deposition from suburban air can support the accumulation of PCDD/F in southern Lake Michigan but some non-atmospheric sources to northern Lake Michigan are implicated. Lake Ontario may be receiving >70% of its current inputs of PCDD/F from non-atmospheric sources.