Toxic metals are natural components of the environment, but human activities, notably industrial and mining processes, have been responsible for the wider diffusion of these elements. The transport, residence time, and fate of pollutants in an ecosystem are serious social concerns. This monograph tries to trace the behaviour of heavy metals in the system soil-plants- animals. We studied the connection between the total quantity and the mobile forms of Pb, Cd, Zn and Cu in soils with different levels of contamination, the transition of these metals into rapeseed and their assimilation by rabbits, fed with a food that consists mainly of rapeseed. We hope that this investigation will contribute to enhancing the knowledge on heavy metals'' behaviour in the system soil-plants-animals. The monography is addressed mostly to specialists, involved in research in the field of agrarian science and ecology, as well as to a large public interested in learning about the problems and risks involved in environmental contamination.