Lead, cadmium, and arsenic residues in animal tissues in relation to those in their surrounding habitat

Abstract

The relationships of the residues of lead, cadmium, and arsenic in animal tissues to those in surrounding vegetation and soil were determined in a natural habitat representing a wide range of such residues. The samples studied were selected from 18 different locations. Analyses were performed on a total of 113 animals, 332 plant specimens (representing 33 species), and 408 soil samples (taken at different depths). For the purpose of evaluating relationships, the samples from each location were averaged and reported as parts per million on a dry weight basis. The average lead residues from different locations ranged from 1.4-9.2 ppm in the liver, 45-195 in bones, 4-283 in vegetation, and 15-1399 in soil samples. The cadmium contents ranged from 1-27 ppm in the liver, 3-77 in bones, 0.5-5 in vegetation, and 1-10 in soil. The arsenic contents in different components of the ecosystem varied with an average of 1-9 ppm in liver, 0.6-94 in vegetation, and 7-655 in soil samples. The soil residues varied considerably according to the depth of sampling. Little variation was noted in different species of vegetation or in soil and vegetation samples according to the time and year of sampling. Statistical analyses performed on the averages indicated a significant correlation between vegetation and soil residues for all three elements, and also between animal to vegetation and animal to soil cadmium residues. Multiple linear correlations for all elements in soil, vegetation, and animal tissues were determined. The results indicated a possibility of an increase in cadmium in animal tissues depending upon the increased residues of this metal in the environment.