-nitrosodimethylamine (NDMA) is a carcinogenic disinfection byproduct that forms during chloramine disinfection of municipal wastewater effluents which are increasingly used to augment drinking water supplies due to growing water scarcity. Knowledge of wastewater NDMA precursors is limited and the known pool of NDMA precursors has not closed the mass balance between precursor loading, precursor NDMA yield, and formed NDMA. Benzalkonium chlorides (BACs) are the most prevalent quaternary ammonium surfactants and have antimicrobial properties. The extensive utilization of BACs in household, commercial and industrial products has resulted in their detection in wastewater at elevated concentrations. We report the formation of a potent NDMA precursor, benzyldimethylamine (BDMA) from the biodegradation of BACs during activated sludge treatment. BDMA formation and NDMA formation potential (FP) were functions of BAC and mixed liquor suspended solids concentration at circumneutral pH, and the microbial community source. Sustained exposure to microorganisms reduced NDMA FP through successive dealkylation of BDMA to less potent precursors. BAC alkyl chain length (C – C) had little impact on NDMA FP and BDMA formation because chain cleavage occurred at the C–N bond. Wastewater effluents collected from three facilities contained BDMA from 15 to 106 ng/L, accounting for an estimated 4 to 38 % of the NDMA precursor pool.

中文翻译：

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废水中苯扎氯铵的细菌脱烷基作用产生苄基二甲胺，一种有效的 N-亚硝基二甲胺前体


-亚硝基二甲胺 (NDMA) 是一种致癌消毒副产品，是在对城市废水进行氯胺消毒过程中形成的，由于水资源日益短缺，城市废水越来越多地用于增加饮用水供应。对废水 NDMA 前体的了解有限，并且已知的 NDMA 前体池尚未实现前体负载、前体 NDMA 产率和形成的 NDMA 之间的质量平衡。苯扎氯铵 (BAC) 是最常见的季铵表面活性剂，具有抗菌特性。 BAC 在家庭、商业和工业产品中的广泛使用导致废水中的 BAC 浓度升高。我们报告了活性污泥处理过程中 BAC 的生物降解形成了一种有效的 NDMA 前体，即苄基二甲胺 (BDMA)。 BDMA 形成和 NDMA 形成潜力 (FP) 是中性 pH 条件下 BAC 和混合液悬浮固体浓度以及微生物群落来源的函数。持续暴露于微生物会导致 BDMA 连续脱烷基化为效力较低的前体，从而降低 NDMA FP。 BAC 烷基链长度 (C – C) 对 NDMA FP 和 BDMA 的形成几乎没有影响，因为链断裂发生在 C-N 键处。从三个设施收集的废水中含有 15 至 106 ng/L 的 BDMA，估计占 NDMA 前体池的 4% 至 38%。