Mercury Depletion Events in the Troposphere in Mid-Latitudes at the Dead Sea, Israel

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• 作者：Mordechai Peleg ; Valeri Matveev ; Eran Tas ; Menachem Luria ; Ralph J. Valente ; Daniel Obrist
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：November 1, 2007
• 年：2007
• 卷：41
• 期：21
• 页码：7280 - 7285
• 全文大小：157K
• 年卷期：v.41,no.21(November 1, 2007)
• ISSN：1520-5851

文摘

The occurrence of mercury depletion events (MDE) in thePolar Regions during the spring periods has raisedglobal concern due to the biomagnifications of the depositedmercury into the aquatic food chain. However, it nowappears that MDE is not limited to the Polar Regions andcan also occur at mid-latitudes. Diurnal cycles of mercury,ozone, and BrO behavior based on short-time resolutionmeasurements are presented for the Dead Sea, Israel,for Summer 2006. The results show that mercury depletionevents occur almost daily, accompanied always by thepresence of BrO and concurrent ozone destruction. Theintensity of the MDE corresponded to increasing BrO levels.Mercury depletions of more than 40% were observedwhen BrO levels rose above 60-70 ppt. Based on the presentmeasurements and supported by theoretical considerations,it appears that BrO_x (BrO + Br) is the primary speciesresponsible for the mercury depletion at the Dead Sea. Thepresent study also suggests, especially at low ozonelevels, that the Br atom may play a major role in conversionof the gaseous elemental mercury to the reactive species,HgBr₂. The implications of the present study are thateven at low BrO levels (<10 ppt), mercury depletion maywell occur at other mid-latitude sites and thus needs to betaken into consideration in the global mercury cycle.