Chloroacetates in snow, firn and glacier ice

A study of chloroacetates in snow, firn and glacier ice was undertaken to d etermine how widespread such compounds are in precipitation and to elucidat e the possible involvement of anthropogenic and natural sources. Samples of snow were collected in remote areas, including Antarctica, the Russian tun dra and northern Scandinavia, and at a few more populated sites. Glacier ic e was sampled at two sites in northern Sweden, and fun from Antarctica was obtained from an archived ice core. Chemical analysis of the collected samp les showed that mono-, di- and trichloroacetate were prevalent in all inves tigated regions, and concentrations of the respective compounds at remote s ites normally ranged from 10 to 100 ng/L. The levels found were too high to be explained by direct anthropogenic emissions of chloroacetic acids or an y of their salts. Furthermore, it was difficult to trace the nearly ubiquit ous occurrence of all three chloroacetates to suggested anthropogenic precu rsors, such as 1,1,1-trichloroethane, trichloroethene and tetrachloroerhene . The presence of mono-, di- and trichloroacetate in glacier ice from north ern Sweden and in firn representing the past 100 years of snow accumulation in Antarctica strongly indicates that chloroacetates may occur naturally i n precipitation (C) 1999 Elsevier Science Ltd. All rights reserved.