Heavy metal and chemical uptake patterns of water and plant (Ipomoea Aquatica) obtained from Agodi Reservoir in Ibadan

Abstract

The basis and mode of heavy metal pollution of sampled water and plant (Ipomoea aquatica) obtained from Agodi Reservoir, Ibadan were investigated in this study. Of interest was possible gradient effect in the reservoir and variations that could be associated with changing climate. The aims were to determine the water quality and estimate ecological resilience of adjoining flora. Chemical analyses of the water samples were done using standard analytical methods while heavy metals in the water and plant samples were determined using Atomic Absorption Spectrophotometer (AAS). Heavy metal concentrations in sampled water were Cd 0.12, Co 0.19, Cu 12.40, Fe 43.75, Mn 64.81, Ni 0.17, Pb 0.005 and Zn 23.12 all measured in mg/L. All of these except for Cu and Pb exceeded the WHO standard. The concentration of heavy metals (mg/kg) in Ipomoea aquatic were Cd 0.24, Co 0.19, Cu 0.31, Fe 153.07, Mn 28.26, Ni 0.03, Pb 5.82 and Zn 35.90. The values obtained for Cd, Fe, Mn and Pb were higher while that of Co, Cu, Ni and Zn were lower to the WHO standards. Among the chemical parameters analyzed, only total hardness (TH) was higher, while SO42-, PO43-, NO3-, Cl- and Alk were lower than the WHO allowable limits for drinking water. One-way analysis of variance (T-statistics) showed that the chemical contents and heavy metals recorded in the water and plant samples were insensitive to their location inside the reservoir, exhibiting no gradient effect. Also, there was no seasonal variation (wet or dry season) in the heavy metal concentration and the chemical parameters measured except for TH which is higher in the dry season. Albeit, the higher concentrations of Cd and Pb in Ipomoea aquatic and Cd, Cu, Fe, Mn, Ni and Zn in the water are concerns for safety when water and plants from the reservoir would, one way or the other, find their way into the food chain.