Temporal And Spatial Variation Characteristics Of Perfluorinated Compounds In Different Water Environments In Qingdao City

In recent years,perfluorinated compounds(PFCs)compounds,as emerging permanent organic contaminants,have become a hot research topic in the academic community due to the uniquely physical and chemical properties and wide existence in the environment.The compounds are persistent against the degradation process and have potential toxicity for organisms.In the present research,water samples from urban rivers,Suburban River,Jiaozhou Bay,and sewage treatment plants(STPs)were collected to investigate the levels and distribution of PFCs in Qingdao city,solid phase extraction(SPE)and high performance liquid chromatography interfaced with a tandem tandem mass spectrometer(HPLC-MS/MS)were applied to determine the concentration of the target compounds including 15 PFAAs and 3 precursors.Besides,the contribution of PFAA precursors were estimated by converting the PFAA precursors in the water samples to perfluorocarboxylates(PFCAs)under oxidation condition.Moreover,the potential ecological risks of PFCs in water were also estimated.The main conclusions are as follows:(1)The PFCs pollution was widespread in waterbodies of Qingdao city.The range(average)concentration of ?PFCs was 3.23-120.65 ng/L(40.02 ng/L)for all the samples.The total concentrations of PFAAs in the water were in the range of 4.42-47.37 ng/L for urban rivers and Jiaozhou Bay and 53.69-112.34 ng/L for STPs effluent in Qingdao city.The average concentration of ?PFCs was 24.75 ng/L for river water,45.54 ng/L for the water of Jiaozhou Bay,and 83.53 ng/L for the STP effluent.Among the target PFCs,PFOS,PFOA,PFHxS,PFHx A,and PFNA were the most abundant compounds.(2)On the whole,the concentration of PFCs was in the order of STP effluent,Jiaozhou Bay,Haipo River,Baisha River,Dagu River.For each river,an increasing trend of ?PFAAs concentration was found from the upstream sites to the downstream sites.Industrial and municipal wastewater and STP effluents are significant pollution sources for PFCs to the aquatic environment of Qingdao city.(3)The concentrations of PFCs showed apparent variations in different waterbodies of Qingdao city.The average concentrations of ?PFAAs in April,August,and November were 38.58 ng/L,43.61 ng/L,and 37.86 ng/L for all the water samples,respectively.Therefore,the total levels of these compounds were obviously higher in August.(4)Although the detection rate and the concentration of precursors were in low levels in water,they are wideapread in the environment.And they are potential to convert into PFAAs.The concentrations of PFCAs were increased obviously after the oxidation treatment.The higher increased concentration of PFCAC4-C12 and lower increased ratios of the compounds were revealed in STP effluents than those in other water bodies,which verified the conversions of precursors into PFAAs during the sewage treatment process in STPs.(5)According to the risk assessment,PFOS pose high ecological risk to aquatic organisms.And PFBA,PFPeA,PFHxA,PFOA,PFBS showed lower risk to aquatic organisms.Considering the transformation from the PFAAs and bioaccumulation along food chain,meuch attention should be payed to the riskof PFCs.