Biological activated carbon (BAC) is widely used as a polishing step at full-scale drinking water plants to remove taste and odor compounds and assimilable organic carbon. BAC, especially with pre-ozonation, has been previously studied to control regulated disinfection by-products (DBPs) and DBP precursors. However, most previous studies only include regulated or a limited number of unregulated DBPs. This study explored two full-scale drinking water plants that use pre-chloramination followed by BAC and chloramine as the final disinfectant. While chloramine generally produces lower concentrations of regulated DBPs, it may form increased levels of unregulated nitrogenous and iodinated DBPs. We evaluated 71 DBPs from ten DBP classes including haloacetonitriles, haloacetamides, halonitromethanes, haloacetaldehydes, haloketones, iodinated acetic acids, iodinated trihalomethanes, nitrosamines, trihalomethanes, and haloacetic acids, along with speciated total organic halogen (total organic chlorine, bromine and iodine) across six different BAC filters of increasing age. Most preformed DBPs were well removed by BAC with different ages (i.e., operation times). However, some preformed DBPs were poorly removed or increased following treatment with BAC, including chloroacetaldehyde, dichloronitromethane, bromodichloronitromethane, N-nitrosodimethylamine, dibromochloromethane, tribromomethane, dibromochloroacetic acid, and tribromoacetic acid. Some compounds, including dibromoacetaldehyde, bromochloroacetamide, and dibromoacetamide, were formed only after treatment with BAC. Total organic halogen removal was variable in both plants and increases in TOCl or TOI were observable on one occasion at each plant. While calculated genotoxicity decreased in all filters, decreases in overall DBP formation did not correlate with decreases in calculated cytotoxicity. In three of the six filters, calculated toxicity increased by 4–27%. These results highlight that DBP concentration alone may not always provide an adequate basis for risk assessment.

生物活性炭（BAC）在大规模饮用水厂中广泛用作抛光步骤，以去除味道和气味化合物以及可吸收的有机碳。先前已经研究了BAC，尤其是进行预臭氧化处理的BAC，以控制受控的消毒副产物（DBP）和DBP前体。但是，大多数以前的研究仅包括受管制的DBP或数量有限的未经管制的DBP。这项研究探索了两个使用预氯化，然后使用BAC和氯胺作为最终消毒剂的大型饮用水厂。虽然氯胺通常会产生较低浓度的受调节DBP，但它可能会形成未受管制的含氮和碘化DBP的水平升高。我们评估了十种DBP类别中的71种DBP，包括卤代乙腈，卤代乙酰胺，卤代硝基甲烷，卤代乙醛，卤代酮，碘化乙酸，在六个不同年龄的BAC过滤器中，碘化三卤甲烷，亚硝胺，三卤甲烷和卤代乙酸，以及特定的总有机卤素（有机氯，溴和碘的总含量）都随着年龄的增长而变化。不同年龄（即手术时间）的BAC可以很好地去除大多数预制DBP。但是，在用BAC处理后，一些预制的DBP很难去除或增加，包括氯乙醛，二氯硝基甲烷，溴二氯硝基甲烷，N-亚硝基二甲胺，二溴氯甲烷，三溴甲烷，二溴氯乙酸和三溴乙酸。一些化合物，包括二溴乙醛，溴氯乙酰胺和二溴乙酰胺，仅在用BAC处理后才形成。两种植物中有机卤素的总去除量是可变的，并且在每种植物中一次观察到TOCl或TOI的增加。虽然在所有过滤器中计算出的遗传毒性均降低，但总体DBP形成的降低与计算出的细胞毒性的降低并不相关。在六个过滤器中的三个中，计算出的毒性增加了4–27％。这些结果表明，单独的DBP浓度可能并不总是为风险评估提供足够的基础。