Distribution and extent of heavy metal(loid) contamination in agricultural soils as affected by industrial activity

Abstract

In Korea, rapid industrialization has often caused severe soil and water pollution near industrial complexes. Particularly, heavy metal(loid) contamination of agricultural lands could induce serious long-term problems for crop safety and productivity, requiring continual safety assessment. This study investigated heavy metal(loid) contamination of agricultural lands near fifteen industrial complexes. At each of industrial sites in Gyeongsangbuk-do, topsoils and subsoils were collected at two different distances from each site (0-500 m and 500-1000 m). For comparison, at each site, non-polluted soils were also collected more than 1000 m away from each industrial complex. With the exception of one sample, heavy metal(loid) concentration of all soils were lower than the Korean guidelines for soil contamination. However, the difference between the heavy metal(loid) concentrations of Cu, Pb and Zn in topsoil and subsoil increased the closer the samples were the industrial complexes, which implied that these elements were being generated by industrial activities and were freshly loaded on to near surface soils. While the heavy metal(loid) concentration in the studied sites did not exceed the Korean guideline, the geoaccumulation index of each soil indicated that the degree of Cd, Cu, and Pb contamination was heavily or extremely serious in more than twenty of the examined soils. The elevation of specific metals associated with industrial activity in soils in close proximity to industrial sites is of some concern and should be taken into consideration for the future management of agricultural soils around such complexes as well as the industrial complex operation itself.