USE OF SOME ORNAMENTAL PLANTS IN PHYTOREMIDATION TECHNIQUE OF SOIL CONTAMINATED WITH SOME HEAVY METALS (NI, CD, PB).

A potting experiment was conducted in plastic house using soil with loam texture, to studying process of phytoremidation of soil contaminated with some heavy metals (Lead, Cadmium and Nickel) using three ornamental plants: : Ficus elastica (Fix) and Catharanthus vinca and Carissa, to evaluate the efficiency of ornamental plants above in absorbing and accumulating the above heavy metals from soil contaminated with them, and to evaluate the contamination of soil and plants with heavy metals by adopting the concentration according to international standards.Seedlings of ornamental plants were planted at one age (three months), they were fertilized with NPK elements according to fertilizer recommendation. They were irrigated with tap water after depleting 35% of available water. The experiment continued for four months. The experiment was conducted globally according to a completely randomized design (CRD) using three ornamental plants and three levels of three heavy metals Pb, Cd and Ni, namely 0, 100 and 200 mg L-1 for Lead, 0, 10 and 15 mg L-1 for Cadmium , 0, 50 and 100 mg L -1 for Nickel with four replications, so that the number of experimental units is 108. Soil samples were taken before and after the end of experiment, and the available and total heavy metals were estimated. Plant samples (leaves) were also taken after the end of experiment, concentrations of heavy metals were estimated. Results showed an increase in total and available concentrations of heavy metals in the cultivated soil and for all plants after the end of experiment, directly with the increase in levels of added heavy metals. Total concentrations of Lead, Cadmium, and Nickel were (32.27, 28.62, and 33.56), (1.593, 1.009, and 1.326) and (12.17, 8.41, and 10.61) mg kg-1 for heavy metals, respectively, for Ficus elastica (Fix) and Catharanthus vinca and Carissa, respectively. Available concentrations, were (12.28, 13.11, 12.63), (0.015, 0.012, 0.022) and (2.5000, 2.247 and 2.453) mg kg -1 for the heavy metals respectively for the above ornamental plants respectively. Soil contamination with heavy metals led to an increase in the concentrations of these elements in the plant (leaves) directly with the increase in levels of addition for all plants. Plants can be arranged in terms of their efficiency in absorbing heavy metals as follows: Catharanthus vinca > Carissa > Ficus elastica, which indicates the high ability of plants to transfer and accumulate heavy elements from soil to plant. As for the heavy metals, they can be arranged according to the amount absorbed from them as follows :