CAPACITY OF SIX PLANT SPECIES TO ACCUMULATE LEAD IN CONTAMINATED SOILS

Abstract

The use of plant species to clean up soils contaminated with heavy metals represent an alternative and inexpensive technology without disturbing the ecosystems, deserving to be studied. The following species: Cenchrus ciliaris, Helianthus annus, Ricinus communis, Nicotiana tabacum, Sorghum sudanens, and Brassica campestris were cultivated in pots in a sandy loam soil artificially contaminated with 0, 500 and 1000 mg Pb kg^-1 soil. The aim of this study was to evaluate the Pb accumulation. These species varied in their capacity to accumulate Pb. In the treatment 500 mg Pb kg^-1 of soil, the Pb extraction capacity (P ≤ 0.05) was: N. tabacum (3.27 y 3.08 mg de Pb kg^-1 total dry matter and shoots, respectively) > R communis > C. ciliaris > S. sudanense > B. campestris > H. annus. In treatment 1000 mg Pb kg^-1 of soil, the order (P ≤ 0.05) was: R. communis (6.79 y 3.94 mg de Pb kg^-1 total dry matter and shoots, respectively) > S. sudanense > C. ciliaris > H. annus > N. tabacum = B. campestris. According to the specialized literature, none of these species can be classified as “Lead hiperaccumulator”.