| Heavy metals are common environmental pollutants,easy to cause harm to organisms,and danger to the food chain.With the rapid development of the industry,a large number of heavy metals go into the environment and it is a threat to human health.Antibiotics is a new class of organic pollutants,a growing number antibiotics can not be fully absorbed after the use of antibiotics by human and animals and absorbed by the soil after wastewater treatment plant,impacting on the aquatic environment,thereby affecting human health.Selected Guangxi Yongjiang River study area,through the study the Yongjiang River surface sediments sampling,testing,data processing and analysis,get the following conclusions:(1)Yongjiang River sediment using microwave digestion and ICP-OES to test the heavy metals content,the average levels is Fe>Mn>Cr>Zn>Cu>Ni>As>Pb>Cd.Cd were not detected,the remaining eight elements in the detection rate of more than 90%.The average content of heavy metals of Yongjiang River sediments are lower than secondary standards of the National Soil.Pb content is lower,reaching primary standard range of the national soil;compared to the northeast of Guangxi region(alluvial deposits)element background values,except Pb content lower than background value,the Cr content is seven times the background value,the content of Cu is four times the background value,As content is three times the background value,Ni,Zn content is 2 times the background value.In addition to the heavy metal content of Cd,Pb,of As outside,the rest of the heavy metal content in the Yongjiang sediments are higher than the content of heavy metals in the topsoil,and heavy metals in the world in soil.Compared with other regional rivers like Huaihe River,Lijiang River,Xiangjiang River,Weihe River and Huangpu River,Cr,Ni,Cu content in Yongjiang River is higher,As content is also slightly higher,just below the heavy metals in Xiangjiang River;Zn content are higher than the content of other rivers except Lijiang River and Huangpu River.(2)Base on the background value of the northeast of Guangxi region(alluvial deposits),using of Hakanson potential ecological risk index and the geological cumulative index to do the evaluation ecological benefits of the Yongjiang heavy metal environmental.Hakanson potential ecological risk index results show that the Yongjiang sediment heavy metal pollution is a minor pollution state;geological cumulative index show the different evaluation:Cr element of moderate pollution;in individual point Cu element of severe pollution,and the remaining points are less contaminated;in individual points Pb are partial to moderate pollution,the remaining minor contamination;Zn show light pollution;As elements of non-polluting.(3)Ten antibiotics categorized into three different groups(macrolides,sulfonamides and trimethoprim)were investigated in surface sediments in Yongjiang River of Nanning city,South China.The results indicated that the four macrolides antibiotics were the predominan pollutants with the detection rates of 100%an average content of 0.52-1.90 ng/g.While the detection rate of sulfonamides and trimethoprim were 0-83%and their average concentrations ranged from 0 to 1.00 ng/g.Overall,the Yongjiang River's antibiotic content was at a low level compared with the data in domestic and international river,but the pollution of the antibiotic resistance genes can not be ignored.Spatially,the pollution of the tributary was the most serious in the sampling sites.The content of macrolides antibiotics from upriver to downriver showed an increasing trend in main stream of Yongjiang River,while the most concent of sulfonamides and trimethoprim was detected in the upriver.Source apportionment showed that macrolides in the downriver were mainly from domestic sewage and medical wastewater,while sulfonamides and trimethoprim in the upriver maybe more related to livestock and poultry breeding and aquaculture. |
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