Occurrence and ecological risk of disinfection byproducts in urban waterbody during the pandemic in the Pearl River Delta

As the economic center of southern China, the Pearl River Delta region (PRDR) pays special attention to public health issues. During the pandemic, intensive disinfection was carried out in the city to prevent the spread of the virus, which resulted in disinfectant residuals elevating and produced large amounts of toxic disinfection byproducts (DBPs) in the urban water environment. For the purpose of surveying the concentration and distribution of urban water DBPs during the outbreak, 57 samples were collected from three urban water matrices in the PRDR, and were analyzed for the common seven types of DBPs, to elucidate their occurrence and ecological risk. Total 31 DBPs were detected, and the average concentrations of various DBPs in the three matrices were in the order of: surface water (1.9-27.5 μg/L) < effluent from wastewater treatment plant (30.5-114.8 μg/L) < hospital wastewater (5.5-168.9 μg/L). Both trihalomethanes (THMs) and haloacetic acids (HAAs) were the two most major DBPs in all three water categories. By comparing the concentration levels of DBPs in different areas, the concentration levels of DBPs in PRDR were not high. In some hospital wastewater, the TOC content may be able to be used as an associative indicator of DBPs content. The results of the risk quotient indicate that HAAs and haloacetonitriles (HANs) pose some ecological risk.