Heavy Metal Pollution of Agricultural Soils in Central Regions of Korea

Abstract

In an effort to establish databases for the heavy metal pollution in agricultural soils in the central regions of Korea, we have measured the HCl-extractable concentrations of six metals (Cd, Pb, Hg, Cu, Zn, and As) from a total of 260 surface soil samples collected during the spring seasons of 1994 and 1995. All of our measurements were made from three different soil groups that were divided by the surrounding environmental characteristics such as: (1) soil group I – cultivated soils within the purely agricultural regions, (2) soil group II – both cultivated and uncultivated soils near various livelihood facilities, and (3) soil group III – mainly cultivated soils near major pollution sources. The mean concentrations for the three soil groups ranged as follows: 0.118–0.146 (Cd), 4.938–6.078 (Pb), 0.045–0.110 (Hg), 2.823–3.501 (Cu), 4.694–7.818 (Zn), and 0.355–0.782 (As) ppm (on dry-weight basis). Comparitive analysis of these data sets indicate many important aspects of metal distributions in agricultural environments. The metal contents for the relatively unpolluted soil environs (groups I and II) were comparable not only between each other but also with previously reported background concentrations. However slight, but systematic, differences were apparent between the data for the group III and the rest. Results of a regression analysis for inter-metal relationships exhibited somewhat contrary patterns wherein the patterns of soil group I were rather comparable to those of soil group III. Although the common occurrences of strong correlations between As and other metals were difficult to account for, the abundant similarities between group I and III suggest that homogeneities in soil composition may exert significant influences on metal-to-metal distribution characteristics.