FIELD TRIALS FOR IN-SITU DECONTAMINATION OF HEAVY-METAL POLLUTED SOILS USING CROPS OF METAL-ACCUMULATING PLANTS

Certain wild plants as well as crop plants, so-called hyperaccumulator s, are able to accumulate large amounts of heavy metals in aerial part s. This property may be exploited for the clean-up of soil contaminate d by metals (phytoremediation), if the yield and metal accumulation ar e big enough to finish remediation within a reasonable period (e.g. fi ve years). Therefore, the ability of various plants to accumulate zinc and cadmium were compared in field trials. The wild species Thlaspi c aerulescens and Alyssum murale as well as the tree Salix viminalis sho wed a strong ability to accumulate zinc and cadmium. However, phytorem ediation of investigated soils contaminated with cadmium (6.6 ppm) or zinc (810 ppm) lasts too long based on present technology. Literature data and preliminary experiments indicate that major obstacles could b e overcome: Yield and metal-uptake rates have to be increased dramatic ally in order to allow remediation within reasonable periods.