Study On Pollution Level And Traceability Of Heavy Metals In Surface Sediment Of Jiehe River(C Section Of Yantai City)

There are a large number of gold smelting,stone processing and other industrial enterprises in Jiehe drainage area.Because of the lag of sewage pipe network and illegal discharge of pollutants in the early years,a large number of heavy metal were discharged into the sediment.And Jiehe drainage area is the focused region of China thirteenth five-years-plan.In order to respond to national requirements,the local government carried out a project named "the ecological restoration and comprehensive renovation of Jiehe river ".It is necessary to study the degree of heavy metal pollution in rivers sediment while carrying out the project,in order to make a reasonable plan.At the same time,to prevent the repeated pollution and to ensure the effect of governance,we need to find the souce of heavy metal.Therefor,the study on heavy metal traceability method need to be implemented.In this paper,the sediments of Jiehe river sections and sewage discharge outlets were studied in the two respects:the heavy metal content and the heavy metal morphological structure.Then two evaluation methods were used to evaluate the river.On that basis,the mathematical statistics was used to explore the method of heavy metal pollutants traceability.At last,the typical pollution companies was analyzed in the region.The relevant conclusions were as follows:(1)The distribution of heavy metals in the river section was not balanced,and the heavy metal pollution in river upstream was much more serious than that in the river downstream.And the concentration of some heavy metals rised up in the end of the river.Cr?Pb did not exceed the standard,the excessive rates of Ni?Cd?Zn and Cu were 33%?100%?66.67% and 50%.The morphology of Pb mainly existed in F4,its F1 level was similar to F3.The morphology of Ni ?Cu and Zn mainly existed in F1 and F4.The morphology of Cr was F4>F2>F3>F1.The morphology of Cd was F4>F3>F2>F1,and this form of structure was more stable.The order of effective form of heavy metals was Ni>Cr>Cd>Cu>Pb>Zn.Cr?Pb did not exceed the standard in the sediment of sewage discharge outlets,and the excessive rates of Ni?Cu?Zn?Cd were 88.89%?22.2%?33.3%?100%.The differences of heavy metals emissions source of the sewage sludge caused the differences in heavy metal distribution.Risk assessment of the river was carried out by two different risk assessment methods.The order of the potential ecological risk of river sections was J1>J3>J2>J6>J4>J5.The order of potential ecological risk of heavy metals was Cd>Cu>Ni>Pb>Zn>Cr.And Cu?Cd had made a major contribution.RAC showed that the order of the risk of heavy metals was Ni>Cu>Zn>Cr>Pb>Cd.And all sections were in medium risk,and in the order of J3>J5>J6>J4>J1>J2.(2)In river sections samples,the coefficient of variation was in the order of Cd>Cu>Pb>Zn>Ni>Cr,Cr was in moderate variation and the others were in highly variable.The coefficient of variation in sewage discharge outlets was in the order of Zn>Cu>Cd>Ni>Cr>Pb,Pb was in moderate variation and the others were in highly variable.There were ignificant positive correlation between Ni and Cr?Cu and Zn.And the correlation of Cu and Zn was more closely.So,the homology of Cu and Zn was stronger.PCA showed that: The main component 1 was industrial source;the main component 2 was waste water and water for farming;the main component 3 was traffic source;the main component 4 was soil.Pb mainly came form component 1?3;Ni and Cr mainly came form component 2?4;Cu and Zn mainly came form component 1;Cd mainly came form component 2?3.All points wrer divided into 4 cluster,cluster 1 included J1?J2?J4?P2;cluster 2 included J4?J5?J6;cluster 3 included P1?P4;cluster 4 included P3?P5~P9.(3)The Jinchiling waste water did not exceed the standard,but it had high content of Cu.The contents of Pb?Ni?Cu?Zn?Cd were all the highest in G2 and their morphological structure were different to that of other points of Guoda samples.So G2 maybe the potential discharge outlets.Pb?Cu?Zn and Cr exceeded the standard in the waste water of typical stone business company.In the soil samples,Ni did not exceed the standard,but the other elements exceeded the standard and reached the maximum value in SC2.The morphological structure of Pb and Cr were similar,and mianly existed in F4.Other elements' morphological structure in SC2 were different from that of other points.so,SC2 maybe the potential discharge outlets of the company.