Accumulation of cadmium, copper, lead, and zinc in soil and vegetation in the proximity of a smelter

Abstract

Soil and plant samples were collected along northeast-southwest and northwest-southeast transects crossing at the site of a smelter, and between transects. The concentrations of Cd, Cu, Pb and Zn in soils and plants decreased with increasing distance from the smelter, indicating the possible location of the source. Analysis of the soil profile established a negative relationship between metal concentration and depth. This suggests an aerial origin of the contamination. Soil samples were also collected in enclosed spaces under houses (protected soil), as well as around these houses (unprotected soil). The average ratios between the metal concentrations in the 0-20 cm layers of unprotected soil and comparable metal concentrations in the protected soil are 7.0 for Cd, 2.9 for Cu, 2.0 for Mn, 2.3 for Pb and 4.8 for Zn. These values serve as a general measure depicting the metal accumulation in the exposed soil. Coupled with the low pH, it indicates a deterioration of the quality of the soil in a region with a high native metal background level.