Particulate manganese oxide (MnOx) deposition in drinking water distribution systems (DWDS) gives rise to the risk of water discoloration at the consumers’ tap; however, its role in the fate and transport of trace organic pollutants in DWDS is not clear. Perfluorooctanoic acid (PFOA), a persistent organic pollutant frequently detected in natural water, was selected to investigate the potential effect of MnOx on its transportation behavior under DWDS conditions through laboratory batch experiments. The results show that PFOA can be greatly combined with MnOx formed in-situ through a Mn(II) oxidation process by free chlorine. However, the accumulation of PFOA by preformed MnOx was negligible. It was found that 1 mg/L Mn captured over 50% of PFOA with an initial concentration of 50 ng/L during oxidation. The water compositions of actual water could contribute to the effect of PFOA accumulation to a certain extent. Characterization of the solid products revealed that PFOA is homogenously embedded into MnOx. The combination of PFOA with MnOx occurs through a bridging effect of Mn(II) between the surface hydroxyls of MnOx and the -COOH group of PFOA. The resulting MnOx-PFOA particles were more inclined to agglomerate, enabling possibly easy deposition onto the pipe wall than ordinary MnOx particles. This study provides insights into the co-occurrence of metal deposits with PFOA and the potential risks posed by PFOA accumulation to consumers through the water distribution process.

饮用水分配系统（DWDS）中的颗粒状氧化锰（MnOx）沉积会增加消费者水龙头上水变色的风险；但是，在DWDS中其在痕量有机污染物的命运和运输中的作用尚不清楚。选择全氟辛酸（PFOA），一种在自然水中经常检测到的持久性有机污染物，通过实验室批量实验研究MnOx在DWDS条件下对其运输行为的潜在影响。结果表明，PFOA可与游离氯通过Mn（II）氧化过程原位形成的MnOx很好地结合。但是，通过预先形成的MnOx积累的PFOA可以忽略不计。发现在氧化过程中，1 mg / L Mn以50 ng / L的初始浓度捕获了超过50％的PFOA。实际水中的水成分可以在一定程度上促进PFOA的积累。固体产物的表征表明，PFOA均匀地嵌入MnOx中。PFOA与MnOx的结合是通过MnOx的表面羟基与PFOA的-COOH基团之间的Mn（II）桥连作用而发生的。所得的MnOx-PFOA颗粒更易于团聚，比普通的MnOx颗粒更容易沉积在管壁上。这项研究提供了有关金属沉积物与PFOA的共存以及PFOA通过水分配过程积累给消费者的潜在风险的见解。PFOA与MnOx的结合是通过MnOx的表面羟基与PFOA的-COOH基团之间的Mn（II）桥连作用而发生的。所得的MnOx-PFOA颗粒更易于团聚，比普通的MnOx颗粒更容易沉积在管壁上。这项研究提供了有关金属沉积物与PFOA的共存以及PFOA通过水分配过程积累给消费者的潜在风险的见解。PFOA与MnOx的结合是通过MnOx的表面羟基与PFOA的-COOH基团之间的Mn（II）桥连作用而发生的。所得的MnOx-PFOA颗粒更易于团聚，比普通的MnOx颗粒更容易沉积在管壁上。这项研究提供了有关金属沉积物与PFOA的共存以及PFOA通过水分配过程积累给消费者的潜在风险的见解。