COMPARATIVE ANALYSIS OF HEAVY METAL BIOACCUMULATION CAPACITIES OF THREE MAJOR YAM SPECIES FROM MINING AND NON-MINING AREAS IN EBONYI STATE, NIGERIA

Abstract

Possible bioaccumulation of metals by crop plants grown within mining sites is a source of fear to many informed consumers. Three main yam species majorly consumed in Ebonyi State were sourced from within the mining sites (Nwakpu Enyigba Community and Ndufu-Alike) of Ebonyi state, Nigeria and were screened for possible bioaccumulation of some heavy metals including: Lead, Mercury, Cadmium, Chromium, Zinc, Arsenic, Copper and Nickel using standard methods. The result showed that water yam from mining sites accumulated highest amounts of copper, mercury, zinc and cadmium while yellow yam from mining sites compared with the water yam from mining sites only in copper concentration but higher in both arsenic and chromium. The concentration of nickel in all the yams could be said to be negligible. It is worthy of note however that water yam from the non-mining sites had no trace of the various metals except for copper. Yellow yam and egum from mining sites both had a lead concentration of 0.03ppm each, while all the yams from non-mining sites had no lead content. The concentrations of nickel were found to be negligible in all the yam samples studied. Although the yams grown in the mining areas contained various levels of the heavy metals studied, it should be noted that the heavy metals are still within the WHO Maximum Allowable Limit and therefore, consumption of yams from such areas may not actually posse any health risk