Endosulfan and -HCH in the Arctic: An Assessment of Surface Seawater Concentrations and Air-Sea Exchange
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- 作者：Jan Weber ; Crispin J. Halsall ; Derek C. G. Muir ; Camilla Teixeira ; Deborah A. Burniston ; William M. J. Strachan ; Hayley Hung ; Neil Mackay ; David Arnold ; Henrik Kylin
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：December 15, 2006
- 年：2006
- 卷：40
- 期：24
- 页码：7570 - 7576
- 全文大小：248K
- 年卷期：v.40,no.24(December 15, 2006)
- ISSN：1520-5851
文摘
Arctic seawater concentrations of two currently usedpesticides, endosulfan and 
-HCH, were collated from avariety of cruises undertaken throughout the 1990s up to 2000for different regions of the Arctic Ocean. Surface seawaterconcentrations for 
- and 
-endosulfan ranged from <0.1-8.8 (mean 2.3) pg/L and 0.1-7.8 (mean 1.5) pg/L, while -HCHconcentrations were ~100 fold higher than -endosulfan,ranging between <0.70 and 894 (mean 250) pg/L.Geographical distributions for -endosulfan revealed thehighest concentrations in the western Arctic, specifically inthe Bering and Chukchi Seas with lowest levels towardthe central Arctic Ocean. In contrast, -HCH revealed higherconcentrations toward the central Arctic Ocean, withadditional high concentrations in the coastal regions nearBarrow, Alaska and the White Sea in northwest Russia,respectively. A fugacity approach was employed to assessthe net direction of air-water transfer of these twopesticides, using coupled seawater and air concentrations.For -endosulfan, water-air fugacity ratios (FR) were all<1 indicating net deposition to all regions of the Arctic Ocean,with the lowest values (0.1-0.2) evident in the CanadianArchipelago. Given the uncertainty in the temperature-adjusted Henry's Law constant (factor ~10), it is plausiblethat equilibrium may have been reached for this compoundin the western fringes of the Arctic Ocean where the highestwater concentrations were observed. Similarly, FRvalues for -HCH were generally <1 and in agreementwith other separate studies, although, like -endosulfan,net deposition predominated over the Canadian Archipelago.In the central and eastern regions of the Arctic Ocean,as well as in the two coastal areas of this study, the fugacityratios for -HCH where ~1 indicating conditions approachingequilibrium. The elevated water concentrations andhigher FRs in these coastal areas support the assessmentthat riverine/coastal sources are important for thischemical, but less so for -endosulfan for which air towater transfer during the ice-free summer months is likelyto be the major contemporary source to the Arctic. It isrecommended that archived extracts of river water bereanalyzed for -endosulfan to confirm this.
-HCH, were collated from avariety of cruises undertaken throughout the 1990s up to 2000for different regions of the Arctic Ocean. Surface seawaterconcentrations for - and -endosulfan ranged from <0.1-8.8 (mean 2.3) pg/L and 0.1-7.8 (mean 1.5) pg/L, while -HCHconcentrations were ~100 fold higher than -endosulfan,ranging between <0.70 and 894 (mean 250) pg/L.Geographical distributions for -endosulfan revealed thehighest concentrations in the western Arctic, specifically inthe Bering and Chukchi Seas with lowest levels towardthe central Arctic Ocean. In contrast, -HCH revealed higherconcentrations toward the central Arctic Ocean, withadditional high concentrations in the coastal regions nearBarrow, Alaska and the White Sea in northwest Russia,respectively. A fugacity approach was employed to assessthe net direction of air-water transfer of these twopesticides, using coupled seawater and air concentrations.For -endosulfan, water-air fugacity ratios (FR) were all<1 indicating net deposition to all regions of the Arctic Ocean,with the lowest values (0.1-0.2) evident in the CanadianArchipelago. Given the uncertainty in the temperature-adjusted Henry's Law constant (factor ~10), it is plausiblethat equilibrium may have been reached for this compoundin the western fringes of the Arctic Ocean where the highestwater concentrations were observed. Similarly, FRvalues for -HCH were generally <1 and in agreementwith other separate studies, although, like -endosulfan,net deposition predominated over the Canadian Archipelago.In the central and eastern regions of the Arctic Ocean,as well as in the two coastal areas of this study, the fugacityratios for -HCH where ~1 indicating conditions approachingequilibrium. The elevated water concentrations andhigher FRs in these coastal areas support the assessmentthat riverine/coastal sources are important for thischemical, but less so for -endosulfan for which air towater transfer during the ice-free summer months is likelyto be the major contemporary source to the Arctic. It isrecommended that archived extracts of river water bereanalyzed for -endosulfan to confirm this.