Occurrence, seasonal variations, and eco-risk of currently using organochlorine pesticides in surface seawater of the East China Sea and Western Pacific Ocean.

We studied 19 targets currently using organochlorine pesticides (CUOCPs) from 98 samples in the Western Pacific Ocean and the East China Sea collected in 2019, 2020, and 2021. The samples were analyzed using a novel High-throat/High-volume Solid-Phase Extraction method. Eighteen individual CUOCPs were above the method detection limits. The levels of ∑CUOCPs ranged from 0.13 to 17.80 ng/L, with an average of 3.13 ± 14.67 ng/L. Dicofol was the main pollutant in the Western Pacific Ocean, while Pyridaben dominated the East China Sea. In the summer, land-source input was the primary source in the Western Pacific Ocean and the East China Sea. Historical residues were the main source in the East China Sea in spring. In the summer, the ecological risk assessment results indicated a relatively low risk to the Western Pacific Ocean and the East China Sea.