SITE INVESTIGATION AND REMEDIAL STUDY AT DARAKDAE ARTILLARY SHOOTING RANGE FOR FULL SCALE PHYTO- AND BIOREMEDIATION

摘要

Darakdae artillery shooting range, located on the Hantan River, Kyunggi, Republic of Korea, has been in operation more than 40 years, since 1957. Major contaminants are explosives and heavy metals. Site investigation estimated 1009 kg of RDX, 591 kg of TNT, 129 kg of Cd, 2,805 kg of Cu, and 123 kg of Pb, spread over 26.3 ha. Two paths of contaminant migration were identified from mountain ridges in which targets are located, to grassland on the foot of a mountain during rainfall. Most of the contaminants were in the topsoil (< 40 cm), but the contaminants have migrated more than 800 m from the target areas. Long-term in situ remediation technologies, phytoremediation and bioaugmentation, which require less labor and equipment, were proposed as remedial options. To demonstrate feasibility of the remediation technologies, an off-site pilot-scale bioassisted-phytoremediation study was conducted with 4 native annual plants and a mixed microorganisms isolated form the contaminated soil. The 4 plants were indian mallow, indian jointvetch, sunflower, and barnyardgrass (Echinochloa crusgalli var. Frumentacea). TNT readily disappeared within two months whereas RDX removal was highest (80.4%) when treated with bioassisted phytoremediation. In addition, Indian mallow uptake of Cu was more than 3 times higher with the addition of the microorganisms. However, translocation of Pb to shoot was noticed only in sunflower.