Conference proceeding
Seasonal air-water exchange of PCBs in Lake Superior: cycling and mass balance
The 37th conference of the International Association for Great Lakes Research held jointly with Estuarine Research Federation, June 5-9, 1994 , pp.121-121
06/01/1994
Abstract
Instantaneous and seasonal fluxes of PCBs across the air-water interface of Lake Superior were determined based on a bi-modal seasonal source function, matched air-water measurements of PCBs, and wind driven mass transfer coefficents. Gas-phase concentrations of PCBs exhibited maxima in May and August, the latter reflecting the terrestrial signal of air emissions. The concentration peak in May probably reflects a signal from snow melt. Volatilization dominated in late summer and fall in warmer surface waters (15-22 omicron C) while vapor absorption dominated in cool springtime waters (2 omicron C). For 1992, net volatilization was estimated to be similar to 250 kg/yr. Water column concentrations of PCBs have decreased from similar to 2.4 ng/L in 1980 to similar to 0.2 ng/L representing a loss of similar to 26,000 kg and a first order rate coefficient of -0.20 yr super(-) super(1) . Mass balance calculations for 1986, a reference year, suggest net volatilization was about 1,900 kg, compared to sedimentation losses of similar to 110 kg. A PCB congener-specific first order rate constant model shows that k sub(V) sub(O) sub(l) = similar to -0.24 yr super(-) super(1) , while k sub(s) sub(e) sub(d) = similar to -0.004 yr super(-) super(1) . Volatilization of PCBs in Lake Superior is significantly greater than sedimentation and outflow losses, and is facilitated by the poor preservation of organic matter and the efficient recycling of PCBs in the benthic region. Model calculations show that PCB inputs in 1986 must have been about 500 kg, and perhaps 200-300 kg in 1992.
Details
- Title: Subtitle
- Seasonal air-water exchange of PCBs in Lake Superior: cycling and mass balance
- Creators
- K C HornbuckleJ D JeremiasonS J EisenreichC W Sweet
- Resource Type
- Conference proceeding
- Publication Details
- The 37th conference of the International Association for Great Lakes Research held jointly with Estuarine Research Federation, June 5-9, 1994 , pp.121-121
- Publisher
- International Association for Great Lakes Research; Windsor, Ontario
- Language
- English
- Date published
- 06/01/1994
- Academic Unit
- Occupational and Environmental Health; Civil and Environmental Engineering
- Record Identifier
- 9983997982302771
Metrics
16 Record Views