Abstract
The impact of uncontrolled municipal solid waste disposal of 3800 tons per day on surface and groundwater in the downstream of Jawaharnagar dumping site was studied. The un-engineered solid waste dumping yard site spreading over an area of about 300 ha is located on topographic high (hillock), and falls in Madyala stream and Dammaiguda watersheds of Musi sub-basin. The area is underlain by granites of the Archaean age. Both surface and groundwater samples, collected covering hydrological cycles of 2011and 2012, were analyzed for major chemical constituents. During 2012, 15 samples of both seasons were tested for BOD, COD, and TOC. The mean values of some tested chemical constituents of surface water samples (15) were - EC 13066 m S/cm, TH 753, Na+ 813, K+ 530, HCO3− 978, Cl− 1304, and NO3− 262 (all in mg/l) which prove that the tanks and stream near dump yard were pools of leachate. The average values of contaminated groundwater samples among the four sampled sessions (17) indicate EC was above 5000 m S/cm, TH 1624, Cl− 1502, and SO42− 284 (all in mg/l) which were found much above the threshold values. Very few samples were found suitable for drinking purpose and most of the samples fall in Good class of WQI. Very high content of TOC, BOD, and COD in both surface and groundwater samples indicate the presence of organic pollutants sourced from domestic waste dumps. Wide temporal and spatial variability in the concentration of many ion species can be attributed to deviation in rainfall, topography, plume dynamics, and aquifer hydraulics. Low resistivity values (5 to 25 ohm.m) at a distance of 4 km from the dumping site and high infiltration rate (29 cm/hr) at Madyala stream, which were contaminant hotspots, indicate the mass flux was controlled by hydrological features. Scattered and limited distribution of contaminants can be accounted for heterogeneous nature of country rocks, retarded lateral and vertical flow of water which restricts the movement of contaminants to certain preferred pathways. The study supports the hypothesis of solid waste dumps were the epicenter of pollution which generates leachate and dissipate contaminants to the aquatic environment influenced by factors like soils, topography, and aquifer hydraulics and contaminant kinetics.
The impact of municipal solid waste disposal in Ado-Ekiti metropolis, Ekiti-State, Nigeria