RELATIVE UPTAKE OF CADMIUM BY GARDEN VEGETABLES AND FRUITS GROWN ON LONG-TERM BIOSOLID-AMENDED SOILS

Cadmium contamination of soils has been viewed as the most dangerous f orm of trace element contamination of soil. The primary risk posed by Cd contamination is through the ingestion of vegetables grown on Cd-co ntaminated soil. A variety of garden vegetables selected as representa tives of the major food groups were grown on long-term sludge and cont rol plots at high and low pH levels to determine their patterns of Cd uptake in reference to an indicator crop. This was done to determine t he potential for a relative uptake index. This relative uptake index ( RUI) can be used to assess the risk potential for transfer of soil Cd to the food chain for contaminated sites. Lettuce (Lactuca sativa) was used as the indicator crop. For all vegetables excluding dry bean (Ph aseolus vulgaris), which shows very low Cd uptake, it was possible to define a statistically significant log linear relationship with Cd acc umulation in lettuce. When only the more contaminated treatments were included, a more quantitative relation between Cd in the indicator cro p and Cd in the other vegetables (including bean) was defined. This in dicates that a RUI may be appropriate for risk evaluation on more heav ily Cd-contaminated soils.