| In recent years,pharmaceutical and personal care products(PPCPs),which have drawn great attention of environmentalists due to their widespread detection in the environment and the continuous development of environmental toxicology research,have become a hot issue in environmental research.PPCPs refer to a large class of organic compounds produced in service of human activities,including drugs used to prevent or treat human and animal diseases;various main ingredients of personal care products,such as musk,skin care and cleansing products,disinfectants and bactericide chemicals used for disinfection.The sources of PPCPs in the environment are mainly in the form of point sources(like sewage treatment plants)and non-point sources,such as rural domestic sewage and agricultural drainage.Because PPCPs cannot be completely removed in sewage treatment plants,they are widely detected in the aquatic environment.Some PPCPs will have long-term toxicological effects to organisms in the environment at low concentrations(such as endocrine interference),so they can cause risks for the ecosystem of the aquatic environment which cannot be ignored.This study optimized the method of enrichment and analysis of target PPCPs.In this study,the solid phase extraction method was used to enrich the target and the ultra-high performance liquid chromatography tandem mass spectrometry was used for qualitative and quantitative.The sensitivity of this analytical method can reach the ppb level and the lowest detection limit can reach 0.01 ng/L.What’s more,the R2 of the working curve in the experiments can be stabilized over 0.998.This study investigated both the Pearl River estuary in the winter of 2018 and the summer of 2019 and the Jiulong River estuary in the winter of 2018 and spring of 2019.The surface water samples of the estuaries were analyzed to find out the distribution patterns and seasonal variations of 11 PPCPs,and mechanism of the biodegradation of PPCPs in the Pearl River estuary was studied through deck biodegradation experiments.The main conclusions of this research are as follows:(1)Most of the PPCPs are ubiquitous in the surface water of the Pearl River Estuary and the average detection frequencies in winter and summer are 79%and 45.5%,respectively.The concentration of caffeine is the highest in both winter and summer with 579.8 ng/L and 66.4 ng/L,respectively.The detection frequency and concentration of PPCPs in winter were higher than those in summer,the reason of which was that the runoff in summer was greater than that in winter.In addition,both temperature and bacterial abundance in summer were higher than those in winter,which means the rate of microbial degradation of PPCPs is faster.Except gemfibrozil and benzophenone-3,the other detected compounds showed the trend of higher in upstream and lower in downstream.Glibenclamide was conservative during the Pearl River estuary,however,triclocarban,triclosan,caffeine,carbamazepine,hydrochlorothiazide,ibuprofen,gemfibrozil,benzophenone-3 and benzophenone-1 showed a non-conservative trend in the Pearl River estuary.Gemfibrozil and benzophenone-3 showed addition behavior during the mixing process,and other targets exhibited removal phenomena in the estuary.To better understand the microbial degradation of PPCPs,this study conducted field biodegradation experiment to investigate the potential and rate of microbial degradation of PPCPs in Pearl River estuary in winter and summer.The results indicated that the abundance and community structure of microorganisms controlled the degradation of PPCPs,and the difference of temperature caused changes of the biodegradation rate of ibuprofen and hydrochlorothiazide.After 15-days experiment,most compounds can reach the maximum degradation degree,and the results illustrated that the microbial degradation rates of PPCPs were related to the octanol-water partition coefficient of the compounds.(2)The analysis of 11 kinds of PPCPs in the surface water of the Jiulong River estuary,which has a small population,small runoff and relatively low degree of urbanization,found that most PPCPs are also widespread in the Jiulong River estuary.The concentration of benzophenone-1,gemfibrozil and triclocarban in winter is higher than that in spring in the Jiulong River estuary,but the average concentration of caffeine,carbamazepine and triclosan is higher in spring.The reasons why differences of the other compounds in the two seasons were not significant were that the variations of runoff and temperature in winter and spring were not remarkable.The concentration of most targets in the Jiulong River estuary decrease with the increase of salinity.The migration and transformation of triclocarban,benzophenone3,caffeine and carbamazepine in the Jiulong River estuary in winter is conservative.In addition,caffeine and carbamazepine in spring were also conservative.The concentration of benzophenone-3(in spring)and glibenclamide(in winter)increased in the middle salinity area,and there were input phenomena of gemfibrozil and triclosan in both seasons in the middle and lower reaches of Jiulong River estuary.Although the less urbanized of Jiulong River estuary,its per capita emissions of PPCPs are higher than that of the Pearl River Estuary,indicating that the estuaries with low urbanization are also at high risk of environmental pollution. |
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