COMPARISON OF THE ACCUMULATION OF CADMIUM, LEAD AND ZINC IN CULTIVATED AND WILD PLANT-SPECIES IN THE DERELICT ENYIGBA LEAD-ZINC MINE

Twenty-four leaf samples from ten different types of edible crops, and seventeen leaf samples from fifteen wild plant species were collected from various sites on the derelict Enyigba-Abakaliki Lead-Zinc mine, Nigeria in December, 1991. This mine transect had contrasting flora and a few plant species in common. They were analysed for their contents of cadmium (Cd), lead (Pb), and zinc (Zn). Pb seemed to have been accumulated similarly by all the plant species. There was greater uptake of Cd and Zn by the wild plant species. The uptake of the heavy metals by both the edible and wild plants tended decreasingly in the order: Zn > Pb > Cd. It is suggested that the results may indicate more adversary competition between plants for nutrients than is obtainable in a normal environment, with some adaptation/tolerance of the plant species to survival in the harsh environment.