Dynamic Air-Water Exchange of Polychlorinated Biphenyls in the New York-New Jersey Harbor Estuary
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- 作者：Lisa A. Totten ; Paul A. Brunciak ; Cari L. Gigliotti ; Jordi Dachs ; Thomas R. Glenn IV ; Eric D. Nelson ; and Steven J. Eisenreich
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：October 1, 2001
- 年：2001
- 卷：35
- 期：19
- 页码：3834 - 3840
- 全文大小：93K
- 年卷期：v.35,no.19(October 1, 2001)
- ISSN：1520-5851
文摘
Simultaneous measurements of polychlorinated biphenyls(PCBs) in the air and water over Raritan Bay and NewYork Harbor were taken in July 1998, allowing the firstdeterminations of air-water exchange fluxes for this heavilyimpacted system. Average gas-phase concentrations of
PCBs were 1.0 ng m-3 above Raritan Bay and 3.1 ng m-3above New York Harbor. A similar gradient was observedfor dissolved water concentrations (1.6 and 3.8 ng L-1,respectively). Shallow slopes of log KOC vs log KOW plotsindicated a colloidal contribution to the dissolvedconcentrations, and a three-phase partitioning model wastherefore applied. PCBs associated with colloids rangedfrom 6% to 93% for trichloro- to nonachlorobiphenyls,respectively. Air-water gas exchange fluxes of PCBsexhibited net volatilization for both Raritan Bay at +400 ngm-2 day-1 and New York Harbor at +2100 ng m-2day-1. The correction for the colloidal interactionsdecreased the volatilization flux of PCBs by about 15%.Net air-water exchange fluxes of PCBs are expected toremain positive throughout the year due to the large water-air fugacity gradient and relatively constant seasonal waterconcentrations. The volatilization fluxes are approximately40 times greater than atmospheric deposition of PCBsvia both wet and dry particle deposition, suggesting thatthe estuary acts as a net source of PCBs to the atmosphereyear-round.
PCBs were 1.0 ng m-3 above Raritan Bay and 3.1 ng m-3above New York Harbor. A similar gradient was observedfor dissolved water concentrations (1.6 and 3.8 ng L-1,respectively). Shallow slopes of log KOC vs log KOW plotsindicated a colloidal contribution to the dissolvedconcentrations, and a three-phase partitioning model wastherefore applied. PCBs associated with colloids rangedfrom 6% to 93% for trichloro- to nonachlorobiphenyls,respectively. Air-water gas exchange fluxes of PCBsexhibited net volatilization for both Raritan Bay at +400 ngm-2 day-1 and New York Harbor at +2100 ng m-2day-1. The correction for the colloidal interactionsdecreased the volatilization flux of PCBs by about 15%.Net air-water exchange fluxes of PCBs are expected toremain positive throughout the year due to the large water-air fugacity gradient and relatively constant seasonal waterconcentrations. The volatilization fluxes are approximately40 times greater than atmospheric deposition of PCBsvia both wet and dry particle deposition, suggesting thatthe estuary acts as a net source of PCBs to the atmosphereyear-round.