CERAR - Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095, Australia; CRC CARE - Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106, Australia.
J Hazard Mater. 2013 Oct 15;261:793-800. doi: 10.1016/j.jhazmat.2012.11.061. Epub 2012 Dec 5.
Organoclays have wide spread application in environmental remediation and nanocomposites synthesis. Some of the quaternary ammonium compounds (QACs) commonly used to prepare organoclays are toxic to biota. However, information on the toxicity of organoclays is rarely available in the literature. This study assessed the toxicity of three laboratory prepared bentonite organoclays on the soil microbially mediated processes (such as dehydrogenase activity and potential nitrification) and soil inhabiting animals, such as earthworms. Toxicity to both microbial processes and earthworm followed the order: hexadecyltrimethyl ammonium modified bentonite>octadecyltrimethyl ammonium modified bentonite>arquad modified bentonite>unmodified bentonite. The organoclays were able to cause slight improvement (up to 25%) in the potential nitrification in some soils when they were added at low application rates up to 5%, but caused reduction (3-86%) in the dehydrogenase activity in all the soils irrespective of loading rates. The organoclays were extremely toxic to the survival and vigour of the earthworms. The average body weight loss of the worms reached as high as 62% in hexadecyltrimethyl ammonium modified bentonite treated soil even at 1% loading. This study holds utmost importance in assessing the toxicity of organoclays to soil microbially mediated processes and earthworms.
有机黏土在环境修复和纳米复合材料合成中得到了广泛的应用。一些用于制备有机黏土的季铵化合物（QACs）对生物群具有毒性。然而，关于有机黏土毒性的信息在文献中很少见。本研究评估了三种实验室制备的膨润土有机黏土对土壤微生物介导的过程（如脱氢酶活性和潜在硝化作用）和土壤栖息动物（如蚯蚓）的毒性。对微生物过程和蚯蚓的毒性顺序为：十六烷基三甲基铵改性膨润土>十八烷基三甲基铵改性膨润土>阿夸德改性膨润土>未改性膨润土。当有机黏土以低至 5%的应用率添加时，它们能够在一些土壤中轻微提高潜在硝化作用（高达 25%），但无论负载率如何，都会导致所有土壤中脱氢酶活性降低（3-86%）。有机黏土对蚯蚓的存活和活力具有极高的毒性。在 1%的负载下，用十六烷基三甲基铵改性膨润土处理的土壤中，蚯蚓的平均体重损失高达 62%。本研究在评估有机黏土对土壤微生物介导过程和蚯蚓的毒性方面具有极其重要的意义。
