bioavailability and environmental implications of major and trace metals in manihot esculenta (cassava) grown on shaly and calcareous soils in parts of southern benue trough, nigeria.

Abstract

The study was carried out to investigate the concentration of major and trace metals in shaly and calcareous soil and their uptake in cassava plant parts in order to compare the levels of this metals in both soils as well as the cassava plant growing on the soil. Soil samples (0-30 cm and 30-60 cm) depth and cassava plants (leaves, stems and tubers) were collected from cultivated farm lands and analyzed for major and trace metals. (Ca, K, Al, Na, Fe, Cu, Zn, Pb, Co and Mo) using inductively coupled plasma mass spectrometery (ICP-MS). The pH and L01 of the soil sample were also measured. Results show that calcareous soils were moderately acidic to basic while shaly soils were acidic to neutral. The organic matter content were relatively higher in surface soils than subsurface soils. Levels of metals were generally higher in shaly soils compared to calcareous soils except for Ca, Na, and Mo. Values of enrichment factors revealed deficiency to minimal enrichment (Ef<2) of Al, K, Ca, Fe and Na, moderate enrichment (Ef2-5) of Cu, Zn, and Co and significant enrichment (Ef5-20) of Mo and Pb for shaly soils. In the case of calcareous soils, minimal enrichment was noticed for Al, Fe, K, Cu and Ca while Na, Zn, Pb and Co showed moderate enrichment with only Mo indicated very high enrichment. The principal analysis for cancerous and shaly soils in the study area indicate that the main source of metals are environment, geochemical and anthropogenic activities.