Pentachlorophenol transformation in soil: a toxicological assessment
Pentachlorophenol transformation in soil: a toxicological assessment
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土壤中五氯苯酚的转化：毒理学评估
DOI：
10.1016/s0038-0717(00)00015-8
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发表时间：
2000
影响因子：
9.7
通讯作者：
I. Singleton
中科院分区：
文献类型：
--
作者：
R. McGrath;I. Singleton
生物修复被认为是处理受污染土壤的一种经济上可行的方法，并已提出使用微生物接种剂，特别是白腐菌，以加强修复过程。在生物修复过程中，会产生多种污染物转化产物，这些产物可能具有有毒的协同作用，可能根本不会被化学分析检测到。这项工作研究了在接种了一种常用的真菌接种剂黄孢原毛平革菌后，五氯苯酚(PCP)在土壤中转化过程中形成有毒分解产物的可能性。为了监测生物修复过程中的毒性，测定了土壤脱氢酶活性的变化以及土壤甲醇提取物对一种常见的土壤细菌巨大芽孢杆菌在液体培养中生长的影响。经过6周的修复，土壤中的五氯酚水平已从最初的2 5 0 mg kg−1下降到2 mg kg−1，接种黄孢霉并没有改善未接种五氯酚污染土壤上五氯酚的修复效果。在所有含有PCP的土壤中，土壤脱氢酶活性仍然很低，尽管PCP水平下降，但在整个实验过程中(6周)，土壤脱氢酶活性没有恢复。土壤甲醇提取物对巨型芽孢杆菌的生长有不同程度的毒性，当接种黄孢霉的PCP污染土壤中的甲醇提取物完全抑制巨大芽孢杆菌的生长时，6周后毒性最强。较长的培养时间可能会导致有毒物质的去除，由于土壤甲醇提取物用于生长抑制研究，这些有毒化合物的生物利用度仍然存在疑问。然而，这项工作表明，在生物修复过程中可能会形成有毒转化产物，生态毒理学分析有助于补充污染土壤生物修复过程中的化学分析。
Bioremediation is recognised as an economically viable method to treat contaminated soil and the use of microbial inoculants, in particular, white-rot fungi, has been proposed to enhance the remediation process. During bioremediation, a variety of pollutant transformation products will be created which may have toxic synergistic interactions and may not at all be detected by chemical analysis. This work examined the potential for formation of toxic breakdown products during pentachlorophenol (PCP) transformation in soil after inoculation with Phanerochaete chrysosporium; a frequently used fungal inoculant. To monitor toxicity during bioremediation, changes in soil dehydrogenase activity and effects of soil methanol extracts on the growth of a common soil bacterium Bacillus megaterium in liquid culture were determined. After 6 weeks of remediation, soil PCP levels had dropped from an initial 250 mg kg−1to 2 mg kg−1, and inoculation with P. chrysoporium did not improve PCP remediation over uninoculated PCP-contaminated soil. Soil dehydrogenase activity remained very low in all soils containing PCP and did not recover throughout the experiment (6 weeks) despite the decrease in PCP levels. Soil methanol extracts varied in their toxicity towards growth of B. megaterium and were most toxic after 6 weeks incubation when extracts obtained from PCP-contaminated soil inoculated with P. chrysosporium completely inhibited B. megaterium. A longer incubation time would probably result in removal of toxic products and as soil methanol extracts were used in growth inhibition studies, the bioavailability of these toxic compounds remains in question. However, this work indicates that toxic transformation products may be formed during bioremediation and that ecotoxicological assays are useful to complement chemical analysis during bioremediation of contaminated soil.