Trace metal levels and speciation pattern in the surface water of Aiba reservoir, after sorption on Amberlite XAD-16 resin.

Abstract

A study was carried out to assess the concentration of five trace metals and speciation pattern in surface water Aiba reservoir in Iwo, Nigeria, after sorption with Amberlite XAD-16. Atomic absorption spectrophotometer was used for estimation of trace metals. The total mean concentrations of trace metals in the surface water of the reservoir was in the decreasing order of Fe (0.47 ± 0.15) > Mn (0.26 ± 0.09) > Zn (0.16 ± 0.07) >Cu (0.07 ± 0.02) >Pb (0.005± 0.001) mg/L. Fe and Mn were above the WHO-specified limit, Zn and Cu were below limit and Pb was exactly equal to the specified limit. The speciation pattern revealed that suspended metal, organic bound, and free metal ions had the highest percentage distribution in Mn and Fe, Pb, Zn and Cu, respectively. The suspended particulate metals and those that are bounded to humic and fulvic acid in the natural organic matter present in water, have very low toxicity. In this study, the free metal ion had the highest percentage of Zn and Cu and this was an indication that they were potentially toxic and may have adverse effects on the aquatic habitats living in the reservoir.