TY - JOUR

T1 - Toxicity of organoclays to microbial processes and earthworm survival in soils

AU - Sarkar, Binoy

AU - Megharaj, Mallavarapu

AU - Shanmuganathan, Devarajan

AU - Naidu, Ravi

PY - 2013/10/15

Y1 - 2013/10/15

N2 - 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.

AB - 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.

KW - Organoclays

KW - Quaternary ammonium compounds

KW - Soil microbially mediated processes

KW - Earthworms

KW - Toxicity

U2 - 10.1016/j.jhazmat.2012.11.061

DO - 10.1016/j.jhazmat.2012.11.061

M3 - Journal article

VL - 261

SP - 793

EP - 800

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

SN - 0304-3894

ER -