Low heavy metal bioavailability in soil at contaminated Korean shooting sites

The bioavailability of metals at eight military shooting ranges in the Kyungkido and Kangwondo districts in Korea was examined through measurements of the metal content of the tissues of plants growing at the sites. Analysis of the metals in soil samples showed that only a small fraction of the total metal in the soil was soluble (soluble Cd, 0.01-0.43 mg/kg; soluble Cu, 1.63-10.05 mg/kg; soluble Pb, 0.01-414.46 mg/kg; and soluble Zn, 0.01-0.32 mg/kg). Correlation analyses of the levels of Cd, Pb, Cu, and Zn in soil samples and in 14 plant species collected near the sites showed that plant concentrations of Cd and Pb (shoot and root) were significantly correlated to the levels of Cd and Pb in the soil, whereas the concentrations of Cu and Zn in shoot and root tissue showed no correlation with the concentrations of metal in soil. Moreover, no direct relationship was found between the soil microbial respiration activity and soil metal concentration. These results indicate that there are only small amounts of bioavailable metal in the soil at the military shooting ranges studied.