Abstract:

Based on the measurements of heavy metals in the samples of sediments collected from 12 sampling points along the moat of Suzhou City of Anhui Province,pollution degrees of heavy metals (V,Cr,Ni,Cu,Zn,As and Pb) of the sediments in the moat were analyzed using Nemero index and sediment enrichment factor,and sources of the heavy metals identified using cluster (Pearson correlation coefficient) and factor analyses. Results show that Cu and Zn was quite high,Ni,As and Pb,moderate,and Cr,low to moderate in pollution degree,while V was nil. In terms of integrated pollution degree of the 7 heavy metals,the 12 sampling sites displayed an order of H7> H10>H3> H9 >H1>H11>H6>H5>H12>H8> H2>H4. Sampling site H7 ranks first in the order because it is quite close to the industrial zone,while Sampling site H4 ends the order because it is located near the juncture of the residential area with the moat. Cluster analysis sorts the pollutions of the 7 heavy metals into Category Ⅰ(Cu,Zn,As and Pb),Category Ⅱ(Cr,Ni) and CategoryⅢ (V) and the elements in each category are quite similar in geochemical process. Factor analysis of the rotated component matrix extracted 3 principal components  (PC1,PC2 and PC3) out of the heavy metal element variables,which tallied quite nicely with the result of the cluster analysis and were adequate to explain 90. 97% of the total variable. Specifically,PC1 (Cu,Zn,As and Pb) is typical of pollution from the transportation and the coal industry,PC2 (Cr and Ni) of machine manufacturing,and PC3 (V) of natural process.

Key words: coal city, moat, sediment, heavy metal, pollution degree, source