[Soil environmental background concentrations in old course of the Yellow River in Shandong Province]

The environmental background concentrations of soil heavy metals, HCH, DDT and organic matter in old course of the Yellow River (Shandong area) were studied. Heavy metals vertical distribution, correlative analysis between organic matter and heavy metals, and the effect of different land use types were analyzed. The results showed that the background concentrations were 13.46 mg x kg(-1) for Cu, 16.23 mg x kg(-1) for Pb, 42.31 mg x kg(-1) for Zn, 30.97 mg x kg(-1) for Cr, 0.090 mg x kg(-1) for Hg, 3.90 mg x kg(-1) for As, 8.01 mg x kg(-1) for Co, 36.42 mg x kg(-1) for V, 426.83 mg x kg(-1) for Mn, 0.063 mg x kg(-1) for Cd, 18.71 mg x kg(-1) for Ni, and 0.74% for organic matter respectively. The detection rates of HCH and DDT were 100% and 60% respectively, and their concentrations were lower than Grade II of environmental quality standard for soils. All the heavy metals in soils were lower than Grade I of environmental quality standard for soils, and were lower than the background concentrations in the whole country, Shandong Province and the Loess Plateau area except for Hg. Mercury was significantly enriched in the surface soil, and the concentration of Cd was higher in the sublayer soil. The differences were significant between the layer 0-20 cm and 20-40 cm for Hg, Cd and organic matter, but not for the other heavy metals. The differences were not significant for environmental background concentrations among different land use types. Organic matter had highly positive correlations with Cu, As, Mn, Pb, Zn, Cr, Co and Ni.