Biester H, Keppler F, Putschew A, Martinez-Cortizas A, Petri M
Institute of Environmental Geochemistry, University of Heidelberg, INF 236, 69120 Heidelberg, Germany.
Environ Sci Technol. 2004 Apr 1;38(7):1984-91. doi: 10.1021/es0348492.
Natural formation of organohalogen compounds can be shown to occur in all natural environments. Peat bogs, which are built up exclusively of organic matter and cover approximately 3% of the total continental world area, are potentially significant reservoirs for organohalogen formation. Up to now, fluxes and retention rates of halogens and organohalogen formation in peat bogs were mostly unquantified. In our study, we investigated the retention of atmospheric derived halogens and the natural formation of organohalogens by differential halogen analysis in two peat bogs in southernmost Chile. Atmospheric wet deposition rates of chlorine, bromine, and iodine range between 600 and 36000, 6 and 160, and 1 and 3 mg m(-2) yr(-1), respectively. Mean annual net accumulation rates of these halogens in peat are calculated to be 12-72 mg of Cl m(-2), 1.7-12 mg of Br m(-2), and 0.4-1.2 mg of l m(-2). Retention rates are similarly high for iodine (36-46%) and bromine (7.5-50%), and substantially lower for chlorine (0.2-2%). To evaluate influences of peat decomposition processes on halogen enrichment, halogen concentrations were compared to carbon/nitrogen ratios (C/N). Our results indicate that up to 95% of chlorine, 91% of bromine, and 81% of iodine in peat exist in an organically bound form. The results also indicate that the concentrations of halogens, especially of bromine and iodine, in peat are largely determined by peat decomposition processes and that halogens are not conservative in bogs.
已证明在所有自然环境中都会自然形成有机卤素化合物。泥炭沼泽完全由有机物质构成，覆盖了全球大陆总面积的约3%，是有机卤素形成的潜在重要储存库。到目前为止，泥炭沼泽中卤素的通量和留存率以及有机卤素的形成大多未被量化。在我们的研究中，我们通过差异卤素分析，对智利最南端的两个泥炭沼泽中大气来源卤素的留存和有机卤素的自然形成进行了调查。氯、溴和碘的大气湿沉降率分别在600至36000、6至160以及1至3毫克每平方米每年之间。这些卤素在泥炭中的年平均净积累率经计算分别为每平方米12至72毫克的氯、每平方米1.7至12毫克的溴以及每平方米0.4至1.2毫克的碘。碘（36 - 46%）和溴（7.5 - 50%）的留存率同样很高，而氯的留存率（0.2 - 2%）则低得多。为了评估泥炭分解过程对卤素富集的影响，将卤素浓度与碳/氮比（C/N）进行了比较。我们的结果表明，泥炭中高达95%的氯、91%的溴和81%的碘以有机结合形式存在。结果还表明，泥炭中卤素的浓度，尤其是溴和碘的浓度，在很大程度上由泥炭分解过程决定，并且卤素在沼泽中并非保守性的。
