Evaluation of Toxic Metal Accumulation in Calotropis procera

Abstract

Calotropis procera samples around municipal waste contaminated sites within
Bauchi L.G.A were analyzed for heavy metals using the Atomic Absorption
Spectrophometer, in order to determine the ability of the plant species to bio-
accumulate these metals. Results showed that mean concentrations of cadmium,
chromium, copper, lead, except manganese and zinc in the aerial parts and root of
the plant samples were higher than the normal ranges in plants and control site
values. The weighted means of the studied metals in the plant in Yelwa were in the
order: Zn (94.93mg/kg)> Mn (81.23mg/kg) > Pb (73.51mg/kg) > Cu (49.10mg/kg) >
Cr (25.21mg/kg)> Cd (3.97mg/kg), while in Wunti Dada, the order was: Cu
(68.67mg/kg)> Mn (53.67mg/kg)> Pb (48.53mg/kg)> Zn (43.07mg/kg)> Cr
(19.94mg/kg)> Cd (9.95mg/kg). ANOVA results indicated that there were no
significant differences among the average concentration factors (CFs) of Cu, Pb, Mn
and Zn in the plant studied in both contaminated sites. Cu has the highest CF values
of 0.71±0.07mg/kg while that of Cd (0.21±0.03) was the lowest. The order for the
translocation ratio (TR) for the metals in the plants were Pb (2.81)> Mn (2.22)> Cr
(1.92)> Zn (1.14)> Cu (0.88)> Cd (0.23). The high TRs values for these metals are an
indication that the plant has the potential to phyto-extract these metals from
contaminated soils.