The Applications of Chemical Analyses of Sediments and Soils in ...

near a large zinc smelter in Japan with 20-88 ppm in the soil(Kobayashi, 1972). Similarfindings were made by other observers (Lagerwerff et al, 1973; Buchauer, 1973).Near a battery plant, oat shoots contained 16-19 ppm with 46 ppm in the soilwhereas the control was 0.51 - 0.86 ppm Cd in soil and 1.3 ppm Cd in the shoots (Johnet al, 1972). Cadmium concentration is often high in sewage sludge; however,conflicting results have been obtained on its uptake from plants grown on soil treatedwith sludge. In one test, a significant increase in Cd in soybean was obtained in soiltreated with sludge containing 227 ppm (dry wt.) Cd over three years (Jelinek, 1973).Cadmium is adsorbed on soils according to soil Langmuir adsorption isotherms(John, 1972).ZINCZinc is less important toxicologically, because of the wide range between normalenvironmental levels and toxic levels. It is normally found in high concentration inassociation with lead and cadmium in soils close to smelters. "Availability"of the zincpresent in the soil varies for different species of plants. Similarly, in animal nutrition"plant" zinc is less absorbable because of the formation of insoluble phytates (O'Delland Savage, 1960) whereas soluble chelates may be formed with "animal" zinc , suchas with amino acids (Evans et al, 1974).Zinc is more available to plants under acid soil conditions than under basic11