Evaluation of heavy metal contamination and implication of multiple sources from Hunchun basin, northeastern China

Present concentrations and distributions of heavy metals through profiles, surface soil, and stream sediment samples in the Hunchun area, north-easter n China, were investigated to determine the elemental background values. Th is study also aims to characterize potentially toxic materials such as pulv erized fly ash (PFA) from power stations or ash and slag from coal used dom estically in urban areas, agrochemicals applied inappropriately, and urban sewage sludges from Hunchun City, as well as to ascertain the possibility o f natural enrichment through site characterization by mineralogical and geo chemical investigation. The distribution of contaminants in the alluvial so ils (fluvisol) of this area has been influenced by several interacting fact ors. The parent alluvial materials from weathered products of amphiboles ha ve made coatings such as ferrihydrite, goethite, and hematite. This natural inheritance factor is supported by the fact that the concentrations of wea k acid-extractable (plant-available) heavy metals are very low, except for Fe and Mn. However, in agricultural soils and adjacent stream sediments, an anthropogenic input of Cd, Pb, Ni and Cr by agrochemicals is strongly sugg ested. Also, F contamination by coal combustion and the dissolution of F-be aring minerals could cause some future problems. Wide distribution and sign ificantly high concentrations of Cd, Fe, Mn, and F in soils throughout the combination of pollutants originating from lithogenic and the anthropogenic sources pose potential problems in utilizing water resources.