Prevalence of Some Heavy Metals in Mango and Pawpaw Found inDumpsites of Obio/Akpo and Eleme Local Government Areas in RiverState, Nigeria

摘要

Concentrations of six heavy metals Pb, Cd, Zn, Mn, Cu, and Mg were investigated in dumpsites and non-dumpsites in parts of Rivers State. Similar sizes of two species of fruits mango (Mangifera indica) and pawpaw (Carica papaya) grown at these sites were used for the study. The levels of heavy metals were also investigated in the topsoil at each site. The samples were prepared and digested with mixture of mineral acids HClO4, HCl, H2SO4 and HNO3. They were analyzed by Atomic Absorption Spectrophotometer model 204. The results obtained in mg/Kg showed that heavy metals in mango occurred in the range; Pb (1.34-2.74), Cd (ND - 0.001), Zn (1.09-2.45), Mn (110-178), Cu (2.3-5.20), Mg (0.31-1.73). In paw paw the following were obtained Pb (1.24-1.57), Cd (ND -0.001), Zn (3.84-6.32), Mn (111-115), Cu (2.5-4.11), Mg (1.04-1.84) and in the top soil samples Pb (142-3.66), Cd (ND-0.001), Zn (5.27-8.63), Mn (106-179), Cu (1.24-6.84) and Mg (1.35-1.72). The results revealed that elevated concentrations of heavy metals were obtained in samples from dumpsites when compared to non-dumpsites. The results showed that samples from dumpsites will not be toxic to humans if consumed, as the levels of metals obtained were within standard set by WHO/FAO for daily intake of minerals except for Mn and Pb.