RHA™ anti-Carbaryl monoclonal antibody, clone CBR

The aim of this study was to investigate the biochemical responses in three earthworm species, Eudrilus eugeniae, Perionyx ceylanensis and Perionyx excavatus induced by exposure to pesticide (carbaryl) and metal (lead) in soil. Earthworms were exposed to increasing concentrations of carbaryl (12, 25 and 50 mg kg(-1)) and Pb (75, 150 and 300 mg kg(-1)) in the soil for different periods of time and the biochemical changes were determined. The protein content was slightly increased in E. eugeniae, P. ceylanensis when exposed to the lower concentration of Pb (75 mg kg(-1)). But decreased protein content was observed in P. excavatus at the higher concentration of carbaryl (50 mg kg(-1)), and with exposure to 300 mg kg(-1) Pb in P. ceylanensis. The changes in the levels of antioxidant enzymes glutathione-S-transferase (GST), glutathione peroxidase (GPx), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were used as functional biomarkers to determine the effect of pesticides and metals on earthworms. Among these, GST exhibited more sensitive response to both carbaryl and Pb as compared to the control. Other antioxidant enzymes showed little variation at the time of exposure. The results of our study suggested that both carbaryl and Pb induced the production of Reactive oxygen species (ROS) by causing oxidative damage to cells. Due to an adaptive response of earthworms in contaminated soils, they could be used as significant biomarkers to asses the toxicity in the environment of the soil ecosystem. This is the first report on the comparative study of antioxidant enzyme activities in three earthworm species under normal and stress induced conditions.

Carbamate insecticides, which are common micropollutants in surface waters, were found to generate dichloromethlyamine (DCMA) during chlorination. DCMA formation from other precursors has been reported previously; it is part of the emerging class of nitrogen-based disinfection byproducts (N-DBPs) of health concern in chlorinated water. However, there is a limited understanding about its formation, stability, and toxicity. Four carbamate insecticides (methomyl, carbofuran, carbaryl, and thiodicarb) were examined as DCMA precursors over a range of reaction conditions, based on variables of chlorine/precursor (Cl/P) molar ratio, pH, time, and temperature. DCMA was found to be the dominant volatile DBP to result from chlorination of all four carbamate insecticides, with molar yields ranging from 12% to 150% at a Cl/P molar ratio of 20. Further experiments indicated CH3NCl2 to be relatively stable, with a half-life of up to 35 h in water. The toxicity of CH3NCl2 was investigated using a bacterial bioluminescence inhibition test and survival of human lung tumor cells. The results of these toxicity assays indicated that CH3NCl2 is about 3 orders of magnitude more toxic than CHCl3. CH3NCl2 concentrations in the ppb range were observed to result from chlorination of surface water or tap water samples collected from several different locations in China. The results suggest that precursors to CH3NCl2 formation are ubiquitous and that CH3NCl2 poses a hazard to public health and the environment and should be considered in disinfection chemistry and water treatment.