Fate and ecological risk of legacy and emerging POPs in coastal waters in China.

Short-chain chlorinated paraffins (SCCPs) and dechlorane plus (DPs) are persistent organic pollutants of emerging concern, however, little is known of their fate and ecological risks in coastal waters compared to legacy contaminants in marine environment. Here, we analyzed SCCPs, 2 DP isomers as well as legacy contaminants including 24 organochlorine pesticides and polychlorinated biphenyls (PCBs) in seawater from Hangzhou Bay (HZB) and Liaodong Bay (LDB) for comparison using GC-Orbitrap MS. The total contaminant load in seawater was dominated by SCCPs with the highest detection frequency, in concentrations ranging from 25.38 to 388.23 ng/L in HZB and 7.45 to 144.48 ng/L in LDB, respectively. The congener patterns of SCCPs differed significantly, where HZB was predominated by C-CPs (accounted for 83 %) and C-CPs (40.4 %) was the most abundant in LDB. SCCPs were positively correlated with legacy contaminants in HZB, indicating similar sources. In terms of legacy contaminants, HZB exhibited higher levels of hexachlorobenzene, whereas LDB showed a prevalence of hexachlorocyclohexane. The ocean current in HZB and direct terrestrial input with the impact of intensive human activities around LDB were suggested to attribute to their spatial distribution characteristics, respectively. The contaminants were identified to have medium risks to aquatic organisms by using the risk quotient method. SCCPs contributed most with proportions of 45 % and 80 % for HZB and LDB, the monitoring of which needs to be strengthened in the future.