Evidence of increased gaseous PCB fluxes to Lake Michigan from Chicago
- Rutgers-the State Univ., New Brunswick, NJ (United States). Dept. of Environmental Sciences
- Univ. of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.
Urban-industrial areas exhibit atmospheric concentrations of organic contaminants that are often > 5--10x regional background. Increased emissions of PCBs into the urban-industrial atmosphere leads to enhanced depositional fluxes to proximate waters. In this study, the increased air-water exchange inputs of PCB congeners into southern Lake Michigan driven by elevated atmospheric concentrations emanating from the Chicago, IL/Gary, IN air plume was studied. Intensive experiments were conducted in May and July 1994 and January 1995. The gaseous {Sigma}PCB concentrations at the overlake site 15-km from Chicago ranged from 132 to 1,120 pg/m{sup 3} with higher concentrations occurring in warm periods and when winds were from southerly and westerly quadrants. Dissolved phase {Sigma}PCB concentrations ranged from 48 to 302 pg/L with concentrations in winter {approximately} 2.5 x higher than summer concentrations. Instantaneous net air-water exchange fluxes ranged from {minus}32 (absorption) to + 59 ng/m{sup 2}-d with absorptive flux highest in summer when winds were from the urban area and gas-phase concentrations were highest. Air and surface water temperatures and wind direction were the dominant factors influencing the magnitude and direction of air-water exchange fluxes. The modeled net air-water exchange flux of {Sigma}PCB in the southern quarter of Lake Michigan was {minus} 18 {micro}g/m{sup 2}-yr (net absorption) in 1994, corresponding to 140 kg/yr net input.
- OSTI ID:
- 678051
- Journal Information:
- Environmental Science and Technology, Vol. 33, Issue 13; Other Information: PBD: 1 Jul 1999
- Country of Publication:
- United States
- Language:
- English
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