The Occurrence,distribution And Source Of Emerging Organic Contaminants In Three Typical Rivers

With the rapid development of industry and agriculture,water resources are becoming more and more susceptible to pollution from various sources.In recent years,various organic pollutants have been discharged into the surface water,which has gradually attracted people’s attention.With the advancement of technology and the deepening of research,emerging organic contaminants(EOCs),as a substance that was not of concern in the past,have not been included in traditional monitoring.In recent years,studies have shown that EOCs can cause potential adverse effects on the environment and the human body,even at very low concentrations.For example,organophosphorus flame retardants(OPFRs),bisphenols(BPs),and triclosan(TCS),as EOCs,exhibit neurotoxicity,estrogen effects,and endocrine interference.However,compared with traditional persistent organic pollutants,the research on these emerging pollutants is relatively limit.We selected the Pearl River,Xiaoqinghe River and Lianjiang River,three typical river basins for research.The concentration ranges of sixteen OPFRs,eight BPs,and triclosan were 21.2–91.0,8.46–37.3,and 1.47–5.62 ng/L,respectively,in aqueous samples,and 25.2–492,14.0–86.3,and 0.69–17.5 ng/g,respectively,in SPM samples.Hydrophobic and π-πinteractions could be contributing to the distribution of EOCs.Principal component analysis indicated that consumer materials,manufacturing,and domestic sewage might be the main sources of the EOCs.In addition,our study also investigated the impact of discharges reduction activities on the occurrence of EOCs.The result showed that the concentrations of EOCs did not change considerably before or after discharge reduction activities,although NH3-N showed a substantial decrease following pollution control measure.Thus,temporary reductions of contaminant discharges to the Pearl River had only limited effect on the levels of EOCs.In the Lianjiang River and Xiaoqinghe River,we investigated the occurrence of OPFRs,TBBPA and their metabolites.OPFRs,OPFRs metabolites(m OPFRs),TBBPA,TBBPA metabolites(m TBBPA)were all detected in Lianjiang River,with a range of 220 to 1.4×104,0.11 to 2.35,108 to 3.1×103,4.8 to 414 ng/g,respectively.The concentrations of OPFRs and TBBPA in Xiaoqinghe River were ranged from 4.15 to 31.5,0.76 to 2.51 ng/g,respectively,while m OPFRs and m TBBPA were not detected.The different composition characteristics and spatial distribution have been found in two areas,it could be ascribed to the different local environment and different industry.Most metabolites of OPFRs and TBBPA are shown a strong positive correlation of parent compounds,the average ratio of m OPFRs to OPFRs,debromination products to TBBPA,bromine/chlorine transformation products to TBBPA are ranged from 3.6×10-4 to 2.8×10-3,0.007 to 0.16,2.3×10-4 to 4.0×10-3,respectively.Consider the limit study of metabolites,more research on the occurrence,fate,and toxicity data of metabolites are urgently necessary.In general,the concentration of EOCs in the water phase and particulate phase of the Pearl River is at a medium or low level.The concentration of pollutants in the Lianjiang River is higher than that in Xiaoqinghe River,indicated that the environmental impact of e-waste recycling activities is greater than that of flame retardant manufacturers.The dismantling activities of e-waste such as burning circuit boards may accelerate the metabolism of compounds.In addition,there is a strong positive correlation between metabolites and parents compounds,suggested that they may be degraded from parents compounds in the environment.