Diffusion of heavy metals in plant species occurring in natural and improved grasslands of Sardinia

Although heavy metal (HM) contamination of crops is a matter of concern, such contamination has been little investigated in natural areas. Within the frame of a project funded by Regione Sardegna, we checked the spread of heavy metals in vegetation of natural and improved pasturelands selected according to their proximity to potential sources of pollution. We found a wide range of cadmium (Cd) concentrations, and generally a high Cd concentration in vegetation and soils of pasturelands close to military, industrial and mining areas, compared with control areas. The detected HM concentrations are discussed in terms of their impact on the food chain and compared them to values available in literature in order to ascertain critical values for sheep breeding.