Metals and metalloids in wild asparagus at uncontaminated and mining contaminated sites.

Wild edible plants are considered more healthy than crops because they are unaffected by fertilizers, herbicides and pesticides. However, the occurrence of potentially toxic elements in wild plants is poorly known and needs to be assessed. In this study, 22 elements were determined by ICP-MS in wild asparagus (Asparagus acutifolius L.). Asparagus shoots were collected in uncontaminated environments (20 sites) and areas contaminated by past mining (15 sites) in Sardinia (Italy). Beryllium, Bi, Te, Tl and U in asparagus were undetected (< 0.03 µg g-1), Ag, As, Co, Cd, Li and Sb were very low (median: 0.01 to 0.05 µg g-1), B, Cu, Fe, Mn, Rb and Zn were relatively abundant (median: 10 to 58 µg g-1), and Ba, Mo, Ni, Pb and Sr showed large variations (median: 0.4, 0.3, 3, 0.1 and 0.5 µg g-1, respectively). Median concentrations of detected elements were similar either in asparagus collected in uncontaminated environments or mining related-areas. An exception was Cd in asparagus collected in mining-related areas (median: 1.4 µg g-1) being much higher than asparagus samples in uncontaminated environments (median: 0.01 µg g-1), indicating that high Cd in bedrocks affect contents in asparagus shoots. Also, Sb- and As-rich substrates in mine areas resulted in asparagus with Sb and As concentrations much higher than asparagus samples of predominant Pb-Zn mines. Results of this study indicate potential health hazards to worldwide residents living in areas affected by past mining.