Mountain Cold-Trapping Increases Transfer of Persistent Organic Pollutants from Atmosphere to Cows鈥?Milk

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• 作者：Chubashini Shunthirasingham ; Frank Wania ; Matthew MacLeod ; Ying Duan Lei ; Cristina L. Quinn ; Xianming Zhang ; Martin Scheringer ; Fabio Wegmann ; Konrad Hungerb眉hler ; Silvia Ivemeyer ; Fritz Heil ; Peter Klocke ; Grazina Pacepavicius ; Mehran Alaee
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：August 20, 2013
• 年：2013
• 卷：47
• 期：16
• 页码：9175-9181
• 全文大小：419K
• 年卷期：v.47,no.16(August 20, 2013)
• ISSN：1520-5851

文摘

Concentrations of long-lived organic contaminants in snow, soil, lake water, and vegetation have been observed to increase with altitude along mountain slopes. Such enrichment, called 鈥渕ountain cold-trapping鈥? is attributed to a transition from the atmospheric gas phase to particles, rain droplets, snowflakes, and Earth鈥檚 surface at the lower temperatures prevailing at higher elevations. Milk sampled repeatedly from cows that had grazed at three different altitudes in Switzerland during one summer was analyzed for a range of persistent organic pollutants. Mountain cold-trapping significantly increased air-to-milk transfer factors of most analytes. As a result, the milk of cows grazing at higher altitudes was more contaminated with substances that have regionally uniform air concentrations (hexachlorobenzene, 伪-hexachlorocyclohexane, endosulfan sulfate). For substances that have sources, and therefore higher air concentrations, at lower altitudes (polychlorinated biphenyls, 纬-hexachlorocyclohexane), alpine milk has lower concentrations, but not as low as would be expected without mountain cold-trapping. Differences in the elevational gradients in soil concentrations and air-to-milk transfer factors highlight that cold-trapping of POPs in pastures is mostly due to increased gas-phase deposition as a result of lower temperatures causing higher uptake capacity of plant foliage, whereas cold-trapping in soils more strongly depends on wet and dry particle deposition. Climatic influences on air-to-milk transfer of POPs needs to be accounted for when using contamination of milk lipids to infer contamination of the atmosphere.