ENVIROMENTAL STUDIES OF WATER, SOIL, SEDIMENTS AND PLANT SAMPLES IN SANGO-IJOKODO AREA OF IBADAN, NIGERIA.

Abstract

Increasing population density had led to growth in domestic and commercial activities due to urbanization. This has severe effect on the environment because of indiscriminate disposal of domestic waste and sewages and non-availability of effective waste management. Thus, this study is focused on the evaluation of environmental quality of Sango - ijokodo area of Ibadan. Samples of surface and ground water, soil, sediment and plant were collected from five sampling points across the area. A total of fifty- one samples were collected for analysis. Water samples were analysed for general quality parameters like solids, chloride, sulphate, pH among others using standard methods. Soil and sediments were evaluated for pH, nitrate, phosphate, sulphate, nitrite and total organic carbon. Six metals Fe, Cu, Cd, Pb, Cr and Zn were evaluated in all samples after wet oxidation. The digested samples were subjected to analysis by Atomic Absorption Spectrophotometer to determine metal concentrations .The data obtained were analysed statistically using ANOVA and Duncan multiple range test. The result of water quality parameters revealed that surface water had pH range of 6.82-7.51, Total solid (TS) concentration in the range of 973mg/l-1266mg/l, mean concentration of Cl (154.3mg/l), sulphate (4.126mg\l) while the groundwater had a pH range of 6.32-6.95. The groundwater Total solid (TS) had concentration range from 248- 323mg/l, and had mean concentration of Cl 23.84mg/l, sulphate 2.02mg/l. The mean concentrations of metals in the surface water were Fe (5.7mg / l), Cu (0.37mg/l), Cd (0.02mg/l), Pb(0.74mg/l), Cr (0.38mg/l) and Zn (0.44mg/l).This was generally higher than metals in groundwater with mean concentrations Fe(0.54mg/l), Cu (0.28mg/l), Cd (9.2ug/l), Pb (0.62mg/l), Cr(0.28mg/l) and Zn (0.38mg/l). The soils and sediments in this study area were rich in nitrate, phosphate and sulphate with higher concentrations in soil than sediments. Metals in soils and sediments showed Fe as the most abundant metal with average concentrations 7058mg/kg in soil and 6179mg/kg in sediments. Generally the metals had higher occurrence in soil than sediment with Pb being significantly high in soil. Plant metal concentration are Fe (239.7mg/kg), Cu (10.71mg/kg), Pb (4.54mg/kg), Cr (2.14mg/kg), Zn (87.9mg/kg) while Cd was not detected in the plant. Overall, the domestic activities waste disposal and other anthropogenic activities are negatively affecting the environmental quality of the study area. The ground water is within the regulatory standard limits and may be safe for uses. Fe has seemingly contributed significantly into the environmental media from the natural geological structure of the soil of the area.