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 form of trace element contamination of soil. The primary risk posed by Cd contamination is through the ingestion of vegetables grown on Cd-contaminated soil. A variety of garden vegetables selected as representatives of the major food groups were grown on long-term sludge and control 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 the 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 (Phaseolus vulgaris), which shows very low Cd uptake, it was possible to define a statistically significant log linear relationship with Cd accumulation in lettuce. When only the more contaminated treatments were included, a more quantitative relation between Cd in the indicator crop and Cd in the other vegetables (including bean) was defined. This indicates that a RUI may be appropriate for risk evaluation on more heavily Cd-contaminated soils.