Pollution And Health Risk Assessment Of Heavy Metals In Urban Soil And Dust Near The Mine

The paper took the heavy metals in Tongling City soil and dust for study.68soil and dust samples wree collected accordding differnt land-use types, that istraffic zone, industrial zone, square, residential area, commercial area, cultural andeducational areas. The contamination of heavy metals Pb, Cu, Cr, Zn, Ni, As, Cdand samples’ pH and organic matter were measured. The distribution characteristics,source analysis, and the degree of pollution, potential ecological risks analysis andhealth risk assessment were the five aspects of research. The results can besummarized as follows:(1) The space distribution diagram of heavy metals content can be drawn withordinary Kriging interpolation method based on ArcGIS software. The resultsshowed that: the regularity of spatial distribution of Pb and Cu was not obvious; thecontent of Cr was higher when it was further east; the content distribution of Znwas more uniform in the middle area, and the highest content was in the somewhereof central and southwest; the concentration of Ni was relatively low in the tworegions of southwest and southeast; the content of As had obvious characteristics ofspatial distribution, which was a growing trend from the northwest to the southeast.(2) The results of multivariate statistical analysis showed that there is asignificant correlation between Pb, Cu, Zn, As and organic matter. It can beextracted four principal components by fator analysis: the first main componentincluded Pb, Cu, Zn, As and organic matter; the second, third and fourth maincomponent included Ni, Cr and pH respectively. The content of Pb, Cu, Cr, Zn, Ni,As was mainly influenced by human activities.(3) The results of cumulative index showed that the order of heavy metalpollution levels was Cu> As> Zn> Ni> Cr> Pb. The results of Nemerow pollutionindex method showed that, for different functional areas, the order of pollutionlevels of heavy metals was traffic areas> Square> Industrial Zone> cultural andeducational areas> residential areas> business district.(4) The results of potential ecological risk index with deterministic modelshowed that the order of potential ecological risk factor about six heavy metals wasCu> As> Ni> Pb> Zn> Cr. The potential ecological risk factor of Cu and As was58.04and54.35respectively. RI was up to151.86which had reached a higher riskin soil and dust of Tongling City. And the results of potential ecological risk indexwith blind number model showed that Pb, Cu, Cr, Zn, Ni, and As were in the low level risk and RI was also in low level.(5) The results of health risk assessment with deterministic model and blindnumber model showed that for children the total non-carcinogenic health risks ofPb, Cu, Cr, Zn, Ni, As, Cd from three exposure pathways were6.900and4.706respectively; the carcinogenic risk of As from hand-oral pathway was far morethan the acceptable risk limits recommended by the USEPA. Heavy metal arsenicwas the mian factor which should be concerned in heavy metal pollution of surfacesoil and dust in Tongling City.