Spatiotemporal distribution and fate of typical pesticides in the Bohai Sea and surrounding rivers, China

Abstract

Pesticide leakage has lasting and profound effects on the stability and health of marine ecosystems. To explore the occurrence, distribution, and fate of typical pesticides in marine environments, three sampling campaigns were conducted in the Bohai Sea and surrounding rivers. Atrazine was the most pronounced pesticide, with a high concentration and detection frequency in both seawater and sediment. The presence of typical organophosphorus pesticides (OPs) was significantly lower than historical levels. Pesticide concentrations decreased from inshore to offshore. Furthermore, the spatiotemporal distribution characteristics of the pesticides highlighted the agricultural patterns and differences in pesticide use. Environmental factors and physicochemical properties jointly determined the behaviors and fates of pesticides in the marine environment. Sediment served as both a sink for widely used atrazine and a source of restricted OPs. Although some pesticides have been restricted or banned, such as dimethoate and chlorpyrifos, the risks caused by their long-term use and environmental accumulation cannot be ignored and the normalized monitoring of typical pesticides is necessary in the marine environment.