De Novo Formation of Chloroethyne in Soil

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• 作者：Frank Keppler ; ReinhardBorchers ; John T. G. Hamilton ; Gerhard Kilian ; Jens Pracht ; and Heinz F. Schö ; ler
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：January 1, 2006
• 年：2006
• 卷：40
• 期：1
• 页码：130 - 134
• 全文大小：200K
• 年卷期：v.40,no.1(January 1, 2006)
• ISSN：1520-5851

文摘

To date, chloroethyne in the environment has beenproposed to occur as a reactive intermediate during thereductive dechlorination of tri- and tetrachloroethene withzerovalent metals. Such artificial conditions might possiblybe found at organohalide-contaminated sites that aresurrounded by remediation barriers made of metallic iron.In this paper, it is shown that the highly reactivechloroethyne is also a product of natural processes insoil. Soil air samples from three different terrestrial ecosystemsof Northern Germany showed significant chloroethyneconcentrations, besides other naturally produced monochlorinated compounds, such as chloromethane, chloroethaneand chloroethene. Measured amounts range from 5 to540 pg chloroethyne in air purged from 1 L of soil. A possibleroute of chloroethyne formation in soil is discussed,where chloroethyne is probably produced as a byproductof the oxidative halogenation of aromatic compounds insoil. A series of laboratory studies, using the redox-sensitivecatechol as a discrete organic model compound, showedthe formation of chloroethyne when Fe³⁺ and hydrogenperoxide were added to the system. We therefore proposethat the natural formation of chloroethyne in soil proceedsvia oxidative cleavage of a quinonic system in thepresence of the ubiquitous soil component chloride.