Concentration and bioavailability of cadmium by some plants

A survey was carried out to evaluate the existing level of cadmium in three plant species within and around a refuse site at Ojota, Lagos State, Nigeria. Concentration ranged from background levels to levels well in excess of the maximum tolerable limit in agricultural soils. In the leaves, the least (highest in bracket) of cadmium concentration was 0.24 (4.99)mg/kg while in the roots, it was 0.39 (11.03)mg/kg. The apparent influence of anthropogenic inputs at the refuse site was reflected by the relatively higher concentrations than other sampling locations. The influence of some physicochemical parameters such as pH and Soil organic matter on the relative mobility of cadmium and its redistribution amongst the different plant species was investigated and found to be generally consistent with findings and experimental observations of other workers. An initial evaluation is made of the potential of the species as indicator plants and that vegetables from refuse sites should be avoided and discouraged either as livestock or human feeds