Mutagenic potency in Salmonella typhimurium of organic extracts of soil samples originating from urban, suburban, agricultural, forest and natural areas.
ABSTRACT The purpose of the present work was to assess the mutagenic potency of soil samples presumably not contaminated by industrial wastes and discharges. A set of 51 soil samples was collected from areas considered as not contaminated by a known industrial activity: 11 urban samples (collected in cities), 15 suburban samples (collected in villages), 7 agricultural samples, and 18 forest or natural samples. Each soil sample was collected at the surface (0-5cm deep), dried, sieved (2mm), homogenized before organic extraction (dichloromethane/acetone 1/1 (v/v), 37 degrees C, 4h, soil/solvent ratio 1/2, m/v), solvent exchange to DMSO and sterilizing filtration. The micro-method adaptation of the standard bacterial mutagenicity test on Salmonella typhimurium strain TA98 was performed with and without a metabolic activation system (rat-liver homogenate S9), and thus detected the effect of pro-mutagens and direct mutagens, respectively. The use of a pre-incubation method increased the sensitivity of the assay. The results obtained showed a wide range of effect levels, from no effect to clear mutagenicity. In particular, the extract of all 11 urban soil samples demonstrated mutagenic activity, while the extracts of 10 of the 15 suburban samples showed mutagenicity. On the other hand, the extract of only one of the 7 agricultural samples studied induced mutations, and none of the 18 natural or forest-soil samples investigated produced mutagenic extracts. These findings seem to indicate the crucial influence of the diffuse pollution originating from different human activities on the mutagenic potency of urban soil samples. These findings make it possible to classify the soils according to their mutagenic potency. No clear correlation was found between the mutagenicity detected in soil extracts and the measured polycyclic aromatic hydrocarbon (PAH) content of the soils investigated.
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ABSTRACT: Deoxynivalenol (DON) is the major mycotoxin detected in cereal foods and a risk for human health following DON ingestion could not be excluded due to high level exposure. In this light, the hazard of DON must be carefully evaluated. Therefore, the aim of this study is to perform in vitro genotoxicity tests with DON using the Salmonella typhimurium reverse mutation assay (Ames'test), the comet assay and the micronucleus test in accordance with the OECD test guideline 487 in two human cell lines: the lymphoblastoid TK6 and the hepatoma HepaRG cells. DON gave negative results in the Ames'test performed, both with and without rat liver S9 on three strains TA98, TA100 and TA102. DON elicited cytotoxicity in TK6 and HepaRG cells but did not induce primary DNA damage. DON failed also to induce MN formation in TK6 cells with or without human and rat liver S9. After 24h of treatment, DON induced micronucleus formation in TK6 cells but only at concentrations producing more than 55±5% cytotoxicity. In HepaRG cells, DON highly increased the caspase-3/7 activity but no micronucleus induction was observed. Taken together, our results suggest that DON could be considered as a non in vitro genotoxin.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2014; · 2.99 Impact Factor
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ABSTRACT: In the industrial area of Chinhat, Lucknow (India) wastewater coming from pesticide manufacturing and other industries is used to irrigate the agricultural crops. This practice has been polluting the soil and pollutants might reach the food chain. Gas chromatographic analysis revealed the presence of certain organochlorine pesticides in soil samples. Samples were extracted using different solvents, i.e., hexane, acetonitrile, methanol, chloroform, and acetone (all were HPLC-grade, SRL, India). Soil extracts were assayed for mutagenicity using Ames Salmonella/mammalian microsome test. Mutagenicity was observed in the test samples and TA98 was the most responsive strain for all the soil extracts (irrigated with wastewater) in terms of mutagenic index in the presence (+S9) and absence (-S9) of metabolic activation. In terms of slope (m) of linear dose-response curve for the most responsive strain TA98 exhibited highest sensitivity against the soil extracts in the presence and absence of S9 fraction. Hexane-extracted soil sample (wastewater) exhibited maximum mutagenicity in terms of net revertants per gram of soil in the presence and absence of S9 mix as compared to the other soil extracts. Groundwater-irrigated soil extracts displayed low level of mutagenicity as compared to wastewater-irrigated soil. The soil is accumulating a large number of pollutants due to wastewater irrigation and this practice of accumulation has an adverse impact on soil health.Environmental Monitoring and Assessment 07/2011; 184(5):3013-26. · 1.68 Impact Factor
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ABSTRACT: The residual levels and mutagenic potency of OCPs were studied in surface sediments collected from Taihu Lake, China. The concentrations of OCPs detected in surface sediments revealed a wide range of fluctuation from 4.22 to 461ng/g dry weight (dw). Among the individual components of OCPs, much higher coefficients of variance (0.38-1.57) for each compound were detected, indicating significant difference of OCP residues among different areas over the lake. Mutagenicity of the crude extractable organic matter (EOM) from surface sediments in six typical regions was performed with Salmonella/microsome tests (Salmonella strains TA98 and TA100 with/without metabolic activation S9 mix). TA98 was more sensitive and the main mutagens detected were frameshift toxicants. Sediments collected from the north-west showed higher potency to induce mutagenicity than other regions. Poor correlation between OCP concentrations and mutagenicity suggested OCPs were not responsible for the detected mutagenic effects in sediments. Combining chemical analysis with bioassays will be a novel and useful tool for finding out the responsible environmental mutagens.Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 02/2010; 696(1):62-8. · 4.44 Impact Factor