Distribution Characteristics and Risk Assessment of Pesticides in the Soils of the Water Level Fluctuation Zone of the Three Gorges Reservoir, China
摘要
The water-level fluctuation zone (WLFZ) serves as a critical buffer that intercepts terrestrial pesticides from entering reservoirs and protects aquatic environmental security. In this study, 78 soil samples were collected via systematic sampling from multiple elevations and typical sites across the Three Gorges WLFZ. Pesticides were extracted by modified QuEChERS and quantified with LC‑MS/MS combining non-targeted screening with targeted quantification to investigate residue profiles, spatial patterns and ecological risks. Six pesticides (prosulfocarb, tolfenpyrad, mandipropamid, pyraclostrobin, acetamiprid, and pyroquilon) were universally detected. Among these, acetamiprid was the most prevailent with a mean concentration of 0.23 ± 0.44 mg kg⁻1. The FLA site exibited the highest average residue level (0.73 mg kg⁻1), substantially exceeding those of the other 11 locations; The maximum concentration of 8.12 mg kg⁻1 was recorded at an elevation of 160 m, compared to the regional average of 0.68 mg kg⁻1. Around 92% of samples exhibited a high ecological risk, indicating severe pesticide pollution in local WLFZ. These findings facilitate targeted monitoring, source mitigation and ecological restoration, thereby supporting for scientific reservoir pollution management.