Lead and cadmium in soils and vegetables from urban gardens of Salamanca (Spain).

The Pb and Cd contents of soils and vegetables from 16 urban gardens of Salamanca (Spain) have been determined. The metals were found to occur at concentrations in the ranges 20.1-96.2 and 0.20-0.95 microgram/g for Pb and Cd, respectively. The mean Pb concentration found was 2.60 times higher than that in natural soils of the Salamanca province, whereas that of Cd exceeded its mean concentration in natural and cultivated soils by a factor of 2.73 and 2.04, respectively. The Pb and Cd contents of the vegetables (branches) ranged between 4.17 and The Pb and Cd contents of the vegetables (branches) ranged between 4.17 and 52.7 micrograms/g, and between 0.35 and 3.05 micrograms/g, respectively. According to these results, Pb and Cd occur at pollution levels in the surveyed gardens. The total and soluble Pb (extractable with 1 N ammonium acetate) levels were found to be related to the traffic density. On the other hand, the Cd levels appear to be more closely related to the distance from roadways, as well as to the age of the garden and the flow of visitors.