Assessment of methyl 2-({[(4,6-dimethoxypyrimidin-2-yl)carbamoyl] sulfamoyl}methyl)benzoate through biotic and abiotic degradation modes

Abstract

Detoxification and management of environmental contaminants is an exigent issue of current times. Sulfonylurea herbicide, Bensulfuron-methyl was investigated for its degradation demeanour in soils, through biotic and abiotic modes (biodegradation and hydrolysis). Solid-liquid extraction of the herbicide was followed by GC-MS and UV-visible spectrophotometry analysis. The main metabolites observed were pyrimidinamine [149 m/z] and benzylsulfonamide [182 m/z]. The rate of biodegradation achieved by Aspergillus niger and Penicillium chrysogenum was 95% and 71%, respectively. The maximal decline in Bensulfuron-methyl concentration through hydrolysis was 48%. Furthermore, hydrolytic elimination was also evaluated based on time and pH. Both these parameters had a strong influence on the rate of transformation. Soils with lower pH exhibited an increased rate of degradation while a temperature of 27±2°C gave ideal conditions for herbicide decomposition. Percentage degradation and rate constant (k) followed first order reaction kinetics. Non-inoculated soils displayed less amounts of degradation. Furthermore, relative standard deviations were calculated for the residuals extracted in all soils. Analysis of variance (ANOVA) provided a p value < 0.05 for both strains with R2 closer to 1 signifying the significance of the results. Both fungal strains proved their potential for Bensulfuron-methyl remediation in soils.

Keywords

• sulfonylurea
• gc-ms
• metabolites
• hydrolysis
• herbicide