Browsing by Author "Adebowale, Adeshina Titus"

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    Assessment of groundwater quality in the vicinity of Isale Osun solid waste dumpsite in Osogbo, Osun State. Nigeria.
    (Obafemi Awolowo University, 2015) Adebowale, Adeshina Titus
    This study determined the composition of solid wastes and the physico-chemical quality of groundwaterwithin the vicinity of the Isale Osun solid waste dumpsite. This was with a view to assessing the impact of dumped solid wastes on the groundwater quality of the study area. An area of 1 m2 portion was randomly selected on the dumpsite for three trials. Solid wastes on each of the selected portion were collected, sorted, weighed and classified according to their constituents. Groundwater samples (24) were also collected from six hand-dug wells at varying distance (161 m, 164 m, 206 m, 215 m, 249 m and 362 m ) away from the perimeter of the dumpsiteover the two seasons of annual cycle (dry and rainy seasons)from September 2013 to May 2014. The water samples were analysed for their physico-chemical parameters such as: pH, electrolytic conductivity, apparent colour, turbidity, dissolved oxygen (DO), biological oxygen demand (BOD5), total suspended solids (TSS), total dissolved solids (TDS). The other parameters determined were: alkalinity, acidity and major ions (Cl-, HCO3-, SO42-, Ca2+, Mg2+, Na+, K+), nutrient compounds (NO3-, PO43-) and some heavy metals (Cu, Pb, Cr, Fe, Mn, Cd, Zn). All determinations were carried out using standard instrumental methods involving the use of pH/conductivity meter, flame analyser, colorimeter and spectrophotometer while the main non-instrumental method adopted was volumetric/titrimetric analysis with adequate quality assurance and quality control measures. The data obtained were analysed using the descriptive statistics (mean, range and percentage), ANOVA, regression and correlation analysis, cluster analysis and principal component analysis (PCA). The results showed that theoverall average waste compositions at the dumpsite comprised:food/wood (43.48%), textile (11.02%), papers (8.56%), plastic (4.19%), glass (2.94%), metals (0.64%) while the unclassified component was 11.75%. The physico-chemical parameters such as: pH, conductivity, TDS, acidity, alkalinity, total hardness, HCO3-, PO43-, Cl-, Mg2+, Ca2+, K+, Na+, Zn, Mn, Fe, Cr, Pb, Cu and Cd were significantly (p < 0.05) higher in the water samples collected closer to the dumpsite than those collected further away. However, some of the parameters, notably alkalinity (135.75 mg/L), SO42- (35.88 mg/L), NO3- (1.22 mg/L), HCO3- (162.87 mg/L), Ca2+ (66.77 mg/L), Mg2+ (25.21 mg/L), Na+(18.75 mg/L), were significantly (p < 0.05) higher in the dry than the rainy seasons. Most of the physico-chemical parameters were within the maximum permissible levels recommended by WHO except turbidity (0.37 – 75.50 NTU), TSS (8.0 – 329 mg/L) and acidity (51.45 mg/L). Amongst the heavy metals tested for, only Cd (0.007 mg/L) exceeded the WHO acceptable limit in all the water samples collected during the entire study period. This study revealed that the high concentrations of some of the physico-chemical parameters of groundwater in the study area could be associated to the occurrence of the Isale-Osun dumpsite. The degree of groundwater pollution tended to decrease with distance away from the dumping site.