Zinc and Cadmium Contents of Agricultural Soils and Corn in Northwestern Indiana

Abstract

AbstractSoil and corn (Zea mays L.) leaf and grain samplings were conducted in northwestern Indiana to determine if airborne heavy metal particulates containing Cd and Zn from the northwestern Indiana industrial‐urban complex, situated on the south side of Lake Michigan, were contaminating soils and crops. Sampling in the region revealed no widespread metal contamination. Some metal enrichment had occurred on agricultural soils in Gary and East Gary, Ind. Corn leaf concentrations of Cd, Pb, and Zn fluctuated with sampling location, but grain Cd and Pb levels remained essentially constant at <0.05 and <0.4 µg/g, respectively. A comparison of Zn/Cd ratios in soils, and in corn leaves and grain, suggested that Cd was more actively accumulated in the corn plant but not the grain.Because of the limited acreage affected and the relatively low metal levels observed, no human or animal health problems are expected from harvested crops or silage.The use of log distance vs. log metal concentration in regression analysis showed that the limited metal contamination of agricultural soils was mainly in a southeasterly direction from the industrial‐urban area.