Ecological risk assessment of the typical anti-epidemic drugs in the Pearl River Delta by tracing their source and residual characteristics

Since the outbreak of the COVID-19 pandemic, the anti-epidemic drugs have been used in extraordinary quantities with high intensity, and concerns have grown about their potential ecological risks due to their continued release and persistence in the receiving environments. A systematic investigation, covering the samples from hospital wastewater, effluent from wastewater treatment plants and receiving water bodies in the Pearl River Delta Region (PRDR), was carried out and aimed at tracing the sources and fate of 30 typical anti-epidemic in different water matrixes and evaluating their ecological risk. The results showed that these typical anti-epidemic drugs residues were detected in most of the sampling sites, with the highest concentration measured in hospital wastewater, whose concentrations were as high as ppb level, while the highest concentration of the surface water samples in tributaries was lower than ppb level. Anti-epidemic drugs contained in hospital wastewater and effluent from WWTPs were the main sources of drug residues in surface water in this region. In the surface water of PRDR, although the detected concentration anti-epidemic drugs were basically in the range of 0-10 ng/L. The risk quotient of several anti-epidemic drugs, including Ciprofloxacin (CFX), Ofloxacin (OFX), Erythromycin (ETM), Clindamycin (CLI), and Sulfamethoxazole (SMX), was calculated to be a high value, which indicated that they might cause non-negligible ecological risk to the aquatic environment.