School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK.
Chemosphere. 2010 Apr;79(4):401-7. doi: 10.1016/j.chemosphere.2010.02.003. Epub 2010 Feb 20.
Previous work has indicated that the soil is important to understanding biogeochemical fluxes of trichloroacetic acid (TCA) in the rural environment, in forests in particular. Here, the hydrological and TCA fluxes through 22 in situ soil columns in a forest and moorland-covered catchment and an agricultural grassland field in Scotland were monitored every 2 weeks for several months either as controls or in TCA manipulation (artificial dosing) experiments. This was supplemented by laboratory experiments with radioactively-labelled TCA and with irradiated (sterilised) soil columns. Control in situ forest soil columns showed evidence of net export (i.e. in situ production) of TCA, consistent with a net soil TCA production inferred from forest-scale mass balance estimations. At the same time, there was also clear evidence of substantial in situ degradation within the soil ( approximately 70% on average) of applied TCA. The laboratory experiments showed that both the formation and degradation processes operate on time scales of up to a few days and appeared related more with biological rather than abiotic processes. Soil TCA activity was greater in more organic-rich soils, particularly within forests, and there was strong correlation between TCA and soil biomass carbon content. Overall it appears that TCA soil processes exemplify the substantial natural biogeochemical cycling of chlorine within soils, independent of any anthropogenic chlorine flux.
先前的研究表明，土壤对于理解三氯乙酸（TCA）在农村环境中的生源地球化学通量非常重要，尤其是在森林中。在这里，通过对苏格兰一个森林和沼泽地覆盖的集水区和一个农业草地的 22 个原位土壤柱每隔 2 周进行监测，监测了几个月的水文和 TCA 通量，这些土壤柱作为对照或在 TCA 处理（人工加标）实验中进行。这通过放射性标记 TCA 和辐照（灭菌）土壤柱的实验室实验得到了补充。对照原位森林土壤柱显示出 TCA 净输出（即原位生产）的证据，与从森林尺度质量平衡估计推断的净土壤 TCA 生产一致。与此同时，在土壤中也有明显的证据表明 TCA 大量原位降解（平均约 70%）。实验室实验表明，形成和降解过程都在几天的时间尺度上进行，并且似乎与生物过程而不是非生物过程更相关。土壤 TCA 活性在有机物质更丰富的土壤中更高，特别是在森林中，并且 TCA 与土壤生物量碳含量之间存在很强的相关性。总的来说，TCA 土壤过程表明，在没有任何人为氯通量的情况下，氯在土壤中的大量自然生源地球化学循环确实存在。
