EFFECTS OF SOIL POLLUTION BY HEAVY METALS ON ANNUAL PLANTS IN SAKAI CITY

Abstract

Concentrations of Zn, Cu, Cd, and Pb in surface soils and annual plants, Capsella bursa-pastoris (L.) MEDIK. and Poa annua L., collected from 76 sites in Sakai City near Osaka were measured. The correlations among the concentrations of Cu, Cd, and Pb in the plants were significant (p<0.01), whereas correlations between Zn and the other heavy metals were not significant, and a negative correlation for Capsella suggested an antagonistic relation. Distribution maps of the heavy metals in the plants indicate that the main sources of the pollutants exist in the coastal industrial area and the adjacent downtown area in the northwestern section of the city. A power function was obtained between the distance from the center of pollution and the concentration of the heavy metals in the surface soils and plants. Except for Cd, the mean levels of heavy metal pollution in soils and plants in Sakai City showed that the soil and plant pollution has already progressed too far in Sakai City.