EVALUATION OF 3 HERBACEOUS INDEX PLANT-SPECIES FOR BIOAVAILABILITY OFSOIL CADMIUM, CHROMIUM, NICKEL AND VANADIUM

Uncultivated plants growing on disturbed sites may be useful for asses sing the bioavailability of some metals in soils, and thus the potenti al for metal mobilization up the terrestrial food chain, an important element in ecological risk assessment. A planted chicory cultivar (Cic horium intybus L. var. foliosum Hegi.) and the uncultivated plants hor seweed (Canada fleabane) (Erigeron canadensis L.) and dogfennel (Eupat orium capillifolium (Lan) Small) were evaluated for their ability to a ct as index plant species for soil Cd, Cr, Ni, and V at two field site s where these metals had been applied five yr previously to two highly weathered sandy Ultisols. Soil Cd was available to all analyzed plant tissues of all three plant species at both sites, particularly on the sandier Blanton soil. Chicory was an effective index plant for Cd on the finer textured Orangeburg soil but functioned as an indicator plan t (toxicity symptoms were observed) on the sandier Blanton soil. Horse weed and dogfennel were effective index plants for Cd in both contamin ated soils. Soil Cr, Ni, and V were less bioavailable than soil Cd and plant metal uptake was more sensitive to residual soil Cr, Ni, and V than was soil extraction with double acid. Horseweed and chicory may h ave potential as index plants for soil Cr. Chicory may have potential as a Ni index plant. Chicory and dogfennel may have potential as V ind ex plants.