Cd and Pb contents in soil, plants, and grasshoppers along a pollution gradient in Huludao City, Northeast China.

Cd and Pb contents in soil, plants, and two grasshopper species (Locusta migratoria manilensis and Acrida chinensis) were examined to quantify the influence ranges of zinc smelting on heavy metal contamination. Samples were collected simultaneously from Huludao City, a chemical and nonferrous smelting base in Northeast China. Cd and Pb contamination in soil and plants were serious. Cd and Pb contents were 13.32 and 8.83 mg/kg in L. migratoria manilensis and 16.67 and 15.00 mg/kg in A. chinensis, respectively. Correlation analysis indicated the same metal source for Cd and Pb in soil, plants, and grasshoppers. Cd and Pb contents in soil, plants, and grasshoppers were all significantly related to distances far from the zinc smelter in good negative logarithm model. The fitting curves indicated that the influence radius of the smelter on heavy metal contamination was about 4,000 m for soil and plants and about 2,000 m for grasshoppers.