Geoaccumulation Index and Enrichment Factor to Assess Heavy Metal Contamination in Estuarine Intertidal Sediments and Their Adjacent Arable Soils in Dalian, Northeastern China

An exploratory study on sediment and soil contamination of heavy metals was carried out along Dalian coastal regions in Liaoning province, China. Estuarine intertidal sediment samples and their adjacent upland and paddy soil samples were analyzed by atomic absorption spectrophotometry for Zn, Cu, Pb and Cr. The contamination of the sediments and soils was assessed on the basis of enrichment factor (EF) and geoaccumulation index. The data reveal elevated concentrations of Cu (16.7-25.3 mg kg^-1), Pb (24.2-37.9 mg kg^-1) and Cr (64.5-117 mg kg^-1). Except for Zn, other 3 heavy metals have been accumulated (EF>1). The highest EFs of Cu, Pb and Cr are 1.77, 2.16 and 1.89, respectively. It is possible to suggest the sequence of contamination for Cu, Pb and Cr in the analyzed samples as the following: Pb> Cr > Cu. There is no obvious pollution of Zn in the studied area. For land type, the order of contamination is upland soil > paddy soil > estuarine intertidal sediment. Results of geoaccumulation indices of Zn, Cu, Pb and Cr in samples indicated that the sediment and soil qualities are unpolluted as a whole and varied from unpolluted to low polluted status in Dalian coastal region.