Assessment of heavy metals transfer from a moderately polluted soil into the edible parts of vegetables

In the present study we have grown plants of Brassica oleracea L., Lactuca sativa L. and Lycopersicon esculentum L., widely cultivated in the Mediterranean area, on garden soils contaminated with different amounts of cadmium, copper, nickel and zinc. The aim was to assess the translocation and accumulation of metals into the edible parts of the vegetables in question. Soil contamination caused no symptom of suffering in the species tested; the quantities of metal detected in the edible parts varied significantly both in relation to the metal quantity in the growth substrate and in relation to the plant genotype. The quantities of metals absorbed by the plants are below the critical level of toxicity for the species in question; however, for Cd and, to a lesser extent, Zn, the tolerability levels for foodstuffs are exceeded. This indicates that the use of plants grown on contaminated soils may constitute a hazard for human health.