Tseng Julia K, Bielefeldt Angela R
Department Civil, Environmental, and Architectural Engineering, Univ. of Colorado, 428 UCB, Boulder, CO 80309-0428, USA.
J Environ Qual. 2002 Nov-Dec;31(6):1831-41. doi: 10.2134/jeq2002.1831.
Effective and low-cost strategies for remediating chromium (Cr)-contaminated soil are needed. Chromium(VI) leaching from contaminated soil into ground water and surface water threatens water supplies and the environment. This study tested indigenous Cr(VI) microbial transformation in batch systems at 10 degrees C in the presence of various electron acceptors. The effects of carbon addition, spiked Cr(VI), and mixing highly contaminated soil with less contaminated soil were investigated. The results indicated that Cr(VI) can be biotransformed in the presence of different electron acceptors including oxygen, nitrate, sulfate, and iron. Sugar addition had the greatest effect on enhancing Cr(VI) removal. Less dissolved organic carbon (DOC) was consumed per amount of Cr(VI) transformed under anaerobic conditions [0.8-93 mg DOC/mg Cr(VI)] compared with aerobic conditions [1.4-265 mg DOC/mg Cr(VI)]. Toxicity of high concentrations (< 160 mg/L) of spiked Cr(VI) were not evident. At Cr(VI) concentrations > 40 mg/L, aerobic conditions promoted faster Cr(VI) reduction than anaerobic conditions with nitrate or sulfate present. Biotransformation of Cr(VI) in highly contaminated soil (22,000 mg Cr/kg) was facilitated by mixing with less-contaminated soil. The study results provide a framework for evaluating indigenous Cr(VI) microbial transformation and enhance the ability to develop strategies for soil treatment.
需要有效且低成本的策略来修复受铬（Cr）污染的土壤。铬（VI）从污染土壤中淋滤到地下水和地表水中，会威胁供水和环境。本研究在10摄氏度的批量系统中，在存在各种电子受体的情况下测试了铬（VI）的原生微生物转化。研究了添加碳、添加铬（VI）以及将高污染土壤与低污染土壤混合的影响。结果表明，在包括氧气、硝酸盐、硫酸盐和铁在内的不同电子受体存在下，铬（VI）可以进行生物转化。添加糖对提高铬（VI）的去除效果影响最大。与好氧条件[1.4 - 265毫克溶解有机碳/毫克铬（VI）]相比，在厌氧条件下[0.8 - 93毫克溶解有机碳/毫克铬（VI）]，每转化一定量的铬（VI）消耗的溶解有机碳（DOC）更少。添加的高浓度（<160毫克/升）铬（VI）的毒性不明显。在铬（VI）浓度>40毫克/升时，有氧条件下的铬（VI）还原速度比存在硝酸盐或硫酸盐的厌氧条件下更快。通过与低污染土壤混合，促进了高污染土壤（22,000毫克铬/千克）中铬（VI）的生物转化。研究结果为评估铬（VI）的原生微生物转化提供了一个框架，并增强了制定土壤处理策略的能力。
