Assessment of Heavy Metal Pollution in Estuarine Intertidal Sediments and Soils: A Case Study in Dalian

Abstract

Heavy metal concentrations in estuarine intertidal sediments and adjacent agricultural soils of Dalian, northeastern China were monitored to indicate the status of heavy metal contamination and assess environmental quality of sediments and agricultural soils, which were analyzed by atomic absorption spectrophotometry for Zn, Cu, Pb and Cr. The sediment and soil environmental quality on the base of the environmental background value criteria were evaluated respectively by single- factor pollution index and Nemerow multi-factor pollution index method according to the first grade of Standards for Soil Environmental Quality of China (GB15618-1995). 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 ). Zn concentration is lower than background value. Contamination of Cr was the highest, followed by Pb and Cu. The sequence of pollution degree is upland soil > paddy soil > estuarine intertidal sediment. As for region, contamination degree in order is Biliu estuary region > Yingna estuary region > Fuzhou estuary region. The sediment and soil qualities are unpolluted as a whole and varied from unpolluted to low polluted status in Dalian coastal region.