Abstract:
Due to the high efficiency of pesticides in controlling plant diseases, they are widely used in various agriculture production activities, resulting in a series of environmental problems. Several traditional organochlorine pesticides have been banned due to hazard to ecosystems and human health, and the kinds and usage of emerging pesticides with low toxicity and high efficiency are constantly increasing. This study focuses on four emerging pesticides (trifluralin、chlorothalonil、chlorpyrifos and dicofol) in the Yellow Sea and Yangtze River Estuary. In 2017, surface seawater and sediment samples were collected from the Yellow Sea and Yangtze River Estuary. Gas chromatography mass spectrometry was used to analyze the concentration and spatial distribution of four emerging pesticides in the Yellow Sea and Yangtze River Estuary, and to evaluate their potential ecological risks. The results showed that four emerging pesticides were frequently detected in the Yellow Sea and Yangtze River Estuary, and chlorpyrifos and dicofol were the main pesticides detected. The total pesticides concentrations in water (particulate and dissolved phase) and sediment were 37.56−418.1 pg/L and 215.2−2035 pg/g dw, respectively, indicating that dicofol had a high consumption level in China before being banned. The high polluted areas of four pesticides in seawater are mainly located in North Yellow Sea offshore and Yangtze River Estuary. From nearshore to offshore, the concentration of four emerging pesticides in water showed a slightly decrease trend, which may be related to agricultural activity emissions along the coast. The high values of four emerging pesticides in sediment mostly concentrated in muddy areas. The concentrations of four emerging pesticides in the Yellow Sea were generally higher than that in the Yangtze River Estuary. The ecological risk assessment results showed that the risk level of chlorothalonil exceeded the others, and the overall ecological risk to aquatic organisms was low.