摘要
Introduction:In this study,metal pollution and their sources in surface soils were evaluated by pollution indices and multivariate statistical techniques in association with a geographical information system(GIS).Methods:Surface soil samples were collected in dry season from different locations of Dhaka Aricha highway and analyzed by energy dispersive X-ray fluorescence(EDXRF).Results:Thirteen different metals were found in the tested samples.Pollution indices are determined by enrichment factor in an order of Zr>Sn>P>Mn>Zn>Rb>Fe>Ba>Sr>Ti>K>Ca>Al.The resulting geoaccumulation index(Igeo)value shows the following order:Sn>Zr>P>Mn>Zn>Rb>Fe>Ba>Ti>Sr>K>Ca>Al.Contamination factors(CFs)of the metals range from 1.422 to 3.979(Fe);0.213 to 1.089(Al);0.489 to 3.484(Ca);1.496 to 2.372(K);1.287 to 3.870(Ti);2.200 to 14.588(Mn);5.938 to 56.750(Zr);0.980 to 3.500(Sr);2.321 to 4.857(Rb);2.737 to 6.526(Zn);16.667 to 27.333(Sn);3.157 to 16.286(P);and 0.741 to 3.328(Ba).Pollution load index calculated from the CFs indicates that soils are strongly contaminated by Zr and Sn.Principal component analysis(PCA)of parameters exhibits three major components.R-mode cluster analysis reveals three distinct groups in both site and metal basis clustering that shows a similar pattern with the PCA.Conclusions:These results might be helpful for future monitoring of further increase of heavy metal concentrations in surface soils along highways.
