Occurrence of trace metals of toxicological potential in common grass African foxtail (Cenchrus ciliaris)

Anthropogenic activities often result in the introduction of noxious contaminants into the environment with resultant distribution and transfer across the food chain. This study reports on the level of trace metals (Cd, Pb, Cu and Zn) in African foxtail (Cenchrus ciliaris) plant; widely referred to as “common grass” and possible implication across the food chain. Plant samples were collected from stratified study area, processed and analysed using validated acid leaching protocols. Instrumental analysis of the metallic content was by ICP-OES. Quality assurance of the analytical protocol revealed its’ applicability to the environmental samples through metallic recoveries (n=3) in the range of 85.6 – 91 %. The overall mean concentration of analysed metals in samples ranged from 9.34 mg/kg – 38.6 mg/kg; 64.2 mg/kg – 105.2 mg/kg; 0.28 mg/kg – 0.73 mg/kg and 0.54 mg/kg – 16.3 mg/kg for Cu, Zn, Cd and Pb respectively across SCP1-SCP4. Incremental order of analysed trace metals across the SCPs were Cu: SCP1>SCP2>SCP3>SCP4; Zn: SCP1>SCP2>SCP3> SCP4; Cd: SCP1>SCP2>SCP3 = SCP4 and Pb: SCP1>SCP2> SCP3>SCP4. Strong correlation (r > 0.99) was obtained between all the analysed trace metals. Significant difference at (p < 0.05) was found between the analysed metals and SCP 1 while those between the metals and SCPs 2- 4 were non-significant. Accumulation of these metals in ruminants and transfer across the food chain is most probable.