Pollution Characteristics And Ecological Risk Assessment Of Typical Pharmaceuticals And Personal Care Products (PPCPs) In Offshore And Coastal Rivers Of Qinzhou Bay

Pharmaceuticals and personal care products(PPCPs)as emerging contaminants,which may pose threats to ecosystem and human health,have aroused widespread concern over the last two decades.Qinzhou Bay,located at the vital node of the "Belt and Road",plays an important role in the economic interaction between China and neighboring countries.The rapid development of urbanization has led to a sharp rise in the population of Qinzhou,with multiple phamaceuticals entering the environment in different ways.As a traditional advantageous industry,aquaculture leads to the direct discharge of large quantities of aquaculture pharmaceuticals into Qinzhou Bay.Currently,the researches on PPCPs in Qinzhou Bay are limited to antibiotics,and studies on non-antibiotic PPCPs have not been reported so far.Therefore,the study of non-antibiotic PPCPs in this area is of great significance to local environmental protection.In this study,the pollution characteristics and environmental risks of 15 commonly used non-antibiotic PPCPs in surface water and sediments in the summer and winter of 2017 were investigated in Qinzhou Bay and coastal rivers The results showed that 14 out of 15 target PPCPs were detected.N,N-diethyl-m-toluamide(DEET)and caffeine respectively were the dominant contaminants in the summer and winter,with their highest concentrations up to 33.7 ng/L and 26.8 ng/L.Higher concentrations for most of target PPCPs were observed in winter except for DEET and indomethacin.Spatially,concentrations of PPCPs in the inner bay were generally higher than those in the outer bays,and followed the trend of Qin River>Maowei Sea>Mao ling River>Dafeng River>Qinzhou Outer Bay>Sanniang Bay.11 target PPCPs were detected in the sediments,among which triclocarban,triclosan and DEET were the dominant contaminants in the two seasons,with the highest concentrations of 11.9 ng/g dry weight(dw),6.76 ng/g dw and 3.06 ng/g dw,respectively.In terms of seasonal variations and spatial distributions of PPCPs,sediments are similar to water.The high ratios(>10)of caffeine to carbamazepine showed the direct discharge of large amounts of untreated domestic sewage into the surface water.Principal Component Analysis-Multiple Linear Regression shows that untreated sewage and effluents of sewage treatment plants are the major sources of target PPCPs in water and sediment.The contribution in water was 44.3%and 55.7%,and in sediment was 59.4%and 40.6%Risk assessment indicated that diclofenac posed at least medium risks to aquatic organisms,with one site at a high risk in winter.In addition,the mixture risk quotients(MRQ)of PPCP mixtures ranged from 0.001 to 0.620 and 0.001 to 1.49 in summer and winter.Each MRQ value is higher than the corresponding single PPCP RQ value,indicating that the risk of mixed contaminants to aquatic organisms is higher than that of individual PPCPs.None of the target PPCPs detected in the sediment showed risk due to low concentrations.This work will enrich the information of PPCPs pollution,help to identify potential sources and elaborate the risk of aquatic organisms,providing important insights into the environment management in Qinzhou Bay.