Bentazone is a herbicide, which is frequently detected in groundwater due to its mobility and persistence in aquifers. Groundwater is used as a drinking water source all over the world, and sustainable methods to remove pesticides at low concentrations are urgently needed since pesticide contaminations can adversely affect human health. The aim of this study was to investigate whether microbial bentazone degradation was associated with methane oxidation in full-scale drinking water treatment plants. To this end, we investigated bentazone biodegradation in microcosms with water and filter material from rapid sand filters, or biomass from aeration systems, and we investigated the statistical relation between the presence of methane and bentazone in groundwater abstraction wells. An array of evidence supported an association between bentazone degradation and methane oxidation in the biological treatment process. The biodegradation potential of bentazone was associated with the presence of methane in the raw water at 14 different water works. In contrast, no association was observed with any of the other investigated inorganic energy sources, e.g., ammonium. Addition of acetylene inhibited methane oxidation and the bentazone degradation in filter material from two investigated waterworks. Biomass from the aeration tanks degraded bentazone, but only while oxidizing methane. Bentazone removal rates and methane removal rates correlated significantly across all the experiments with biomass or filter material, with an overall transformation yield of 15 ± 1 × 10–5 moleBTZ/moleCH4. This demonstrated that the bentazone degradation was conducted by the same type of process in all the investigated communities, governed by methane oxidation. Furthermore, based on more than 10.000 water analyses from waterworks abstraction wells in Denmark, bentazone was detected significantly less frequent in wells with high methane concentrations (>1 mg/L) than in wells without methane. This suggests that biological treatment of bentazone contamination in drinking water may be achieved using methanotrophs. Graphical Abstract Conceptual drawing of microbial pesticide degradation processes in drinking water production.

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甲烷氧化对除草剂苯他松在饮用水生产中微生物降解的重要性

苯他松是一种除草剂，由于其在含水层中的流动性和持久性，经常在地下水中检测到。地下水在世界各地被用作饮用水源，由于农药污染会对人类健康产生不利影响，因此迫切需要可持续的方法来去除低浓度的农药。本研究的目的是调查微生物灭草松降解是否与大规模饮用水处理厂中的甲烷氧化有关。为此，我们用来自快速砂滤器的水和过滤材料或来自曝气系统的生物质在微观世界中研究了灭草松生物降解，并研究了地下水抽取井中甲烷和灭草松的存在之间的统计关系。一系列证据支持苯达松降解与生物处理过程中的甲烷氧化之间存在关联。苯达松的生物降解潜力与 14 个不同水厂的原水中存在甲烷有关。相比之下，没有观察到与任何其他研究的无机能源（例如铵）的关联。添加乙炔抑制了来自两个研究水厂的过滤材料中的甲烷氧化和灭草松降解。来自曝气池的生物质降解苯达松，但仅限于氧化甲烷。在使用生物质或过滤材料的所有实验中，苯达松去除率和甲烷去除率显着相关，总转化率为 15 ± 1 × 10–5 mooleBTZ/moleCH4。这表明在所有研究的群落中，灭草松降解是通过相同类型的过程进行的，由甲烷氧化控制。此外，根据丹麦自来水厂抽水井的 10.000 多次水分析，在高甲烷浓度 (>1 mg/L) 的井中检测到苯达松的频率明显低于没有甲烷的井。这表明可以使用甲烷氧化菌实现对饮用水中苯达松污染的生物处理。图形摘要 饮用水生产中微生物农药降解过程的概念图。在具有高甲烷浓度 (>1 mg/L) 的井中检测到苯达松的频率明显低于没有甲烷的井。这表明可以使用甲烷氧化菌实现对饮用水中苯达松污染的生物处理。图形摘要 饮用水生产中微生物农药降解过程的概念图。在具有高甲烷浓度 (>1 mg/L) 的井中检测到苯达松的频率明显低于没有甲烷的井。这表明可以使用甲烷氧化菌实现对饮用水中苯达松污染的生物处理。图形摘要 饮用水生产中微生物农药降解过程的概念图。