Microbial degradation pathways of the herbicide bentazone in filter sand used for drinking water treatment

摘要: The herbicide bentazone is used extensively worldwide, and it frequently detected in groundwater sources for drinking water production. Previously, has been shown to be biodegraded filter sand from biological rapid filters at various waterworks. This untapped potential could an inexpensive sustainable alternative the removal of trace organic contaminants. To study fate identify associated risks, degradation pathways were identified toxicity transformation products was evaluated using quantitative structure–activity relationship (QSAR) modelling. Bentazone investigated microcosm experiments with sand, effluent elevated (5 mg L−1) environmentally relevant concentrations (<10 μg L−1). investigations revealed up 10 products, suggesting three main biotransformation pathways: 1) oxidation isopropyl-moiety corresponding carboxylic acid, 2) aromatic ring leading cleavage subsequent decarboxylation reactions, 3) N-methylation followed by a acid. At concentrations, 92% initial removed within 13 days, this point only one product, carboxy-bentazone, water. QSAR-models considering both human endpoints showed that led detoxification bentazone. Initial processes further degradation, partial mineralization highlights relevance methanotrophs heterotrophs filters.