[Non-targeted Screening and Ecological Risk Assessment of Emerging Contaminants in Beijiang Drinking Water Source of the Pearl River Delta].

Abstract

To investigate the spatial and temporal distribution characteristics and assess the ecological risks associated with emerging contaminants （ECs） in the Beijiang drinking water source, non-targeted screening was conducted using the ultra-high performance liquid chromatography-mass spectrometry technique （UPLC-MS） for one year （June 2022 to May 2023）. This study also involved the quantitative detection of eight typical ECs. The results showed that through the non-targeted screening, a total of 346 pollutants were identified, with industrial materials, pharmaceuticals, and pesticides being the predominant pollutants, collectively accounting for 88.2%. Concentrations of eight representative ECs ranged from n.d （undetected） to 180 ng·L^-1, with detection rates exceeding 80% for six of them. Notably, higher concentrations were found in endocrine disruptors such as bisphenol A （BPA） and 4-nonylphenol （4-NP）, along with the pesticides atrazine （ATZ） and propisochlor （PPS）, with median concentrations ranging from 8.12 to 35.58 ng·L^-1. The concentrations of ATZ, PPS, roxithromycin （ROX）, and ibuprofen （IBU） were significantly higher in the spring season compared to those in other seasons （P<0.05）. Elevated ecological risk levels （RQ>1） were observed at sampling point 1 （S1） and sampling point 3 （S3） for ATZ and Lomefloxacin （LOM）, while for 4-NP, it was determined to be high only at sampling site 2 （S2）. Given their high detection rates and ecotoxicity, particular attention should be paid to ATZ and 4-NP. The concentration level of ATZ exhibited significant seasonal variation due to its agricultural origin, so it is recommended to strengthen control during spring. Overall, this research provides critical insights into a comprehensive understanding of the presence and impact of ECs in this specific region.