CADMIUM AND LEAD CONCENTRATIONS OF COMMERCIALLY GROWN VEGETABLES AND OF SOILS IN THE LOWER FRASER VALLEY OF BRITISH-COLUMBIA

The cadmium (Cd) and lead (Pb) concentrations in various tissues of ec onomically important crops (potato, cabbage, cauliflower, carrot, turn ip, corn and lettuce) grown in three regions within the Lower Fraser V alley were examined in a survey study. The objective of the study was to determine the current concentrations of Cd and Pb in Fraser Valley vegetables and vegetable-producing soils as background data for pollut ion evaluation and reference purposes. Concentrations of both metals i n the vegetable tissues and the soils (based on total metal analysis) were similar to those reported for uncontaminated soils of the world. Cadmium in edible parts of vegetables had site means that varied from 0.03 to 1.74 mu g g(-1) DM, while mean soil Cd in these sites varied f rom 0.17 to 1.02 mu g g(-1). Mean Pb in edible parts of vegetables at these sites varied from 0.03 to 0.16 mu g g(-1) DM, while soils varied from 4.9 to 26.4 mu g Pb g(-1). Potatoes grown on Spetifore soil seri es exhibited a high concentration of Cd in the tubers (site mean of 1. 74 mu g g(-1) DM), and coincided with high extractable soil sulphur an d sodium contents, which showed the influence of a marine environment on that soil. A comparison between a cultivated and uncultivated adjac ent site showed that the soil at the former had almost double the Cd c oncentration of the latter. The Pb concentration at the two sites did not differ. The increased Cd in the cultivated site coincided with a g reater amount of extractable phosphorus and potassium, which may indic ate a history of excessive fertilizer application. No clear relationsh ip was observed between total soil and plant tissue concentration for Cd or Pb. Cadmium was more variable in the plant tissues than Pb, part icularly in the leaves.