Drainage source, distribution characteristics and risk assessment of bisphenol analogues in irrigation canal: a case study in hilly areas in South China.

Bisphenol analogues (BPs), the endocrine-disrupting compounds, have been detected in water, sediment, and even agricultural products. Irrigation is the main way for material migration, and it has been suggested as one of the sources of BPs. But the attention to irrigation water and sediment, and further to the ecological risks, is rare. In a hilly irrigation area in southern China, the partition and accumulation, contribution sources, and potential ecological risk of four bisphenols (BPA, bisphenol S, F, and AF) in the irrigation canal were investigated in the spring of 2023 and 2024. All four BPs were detected in the irrigation water and sediment. BPF was the dominant of 19.6-60.9 ng/L in water, while BPA was still the prominent compound (46.2-54.4% of ∑BPs) in sediment. BPs in the irrigation canal were related to the direct discharge of aquaculture, domestic, and planting drainage. Although low risks for each compound, the comprehensive risk (∑RQ) of sediments went into medium risk. BPF and BPA were the main risk contributors. BPs in sediments increased steadily during the investigation. The special accumulative point was where slow flow maintained, especially caused by the hilly change. This comprehensive study of BPs in hilly irrigation canals should be valuable for reference in similar areas. And it will be beneficial for environmental protection and production safety.