Effects of Leachate from Osisioma Open Dumpsite in Aba, Abia State, Nigeria on Surrounding Borehole Water Quality

Abstract

Samples of leachate from the Osisioma open dumpsite and water from four boreholes from the surrounding residence were collected using the four cardinal point model. The sampled boreholes were assigned BH 1, BH 2, BH 3, and BH 4 with distances of 80, 251, 348, and 455 (m) respectively from the location of the dumpsite which is at the center as regards to the cardinal point model used. Physicochemical and microbiological parameters were analyzed to determine the quality of the water. pH, Conductivity, Temperature, TDS, Colour, alkalinity, DO, BOD, COD, Nitrate, Nitrate-Nitrogen, Iron, Chlorine, Chromium, Copper, Arsenic, Lead, Zinc, total bacterial count, E. coli and total coliform count were analyzed. pH ranged from 5.2 to 6.3 in borehole water indicating toxic pollution and was neutral (7.1) in the leachate sample. The temperature of borehole water and leachate ranged from 26.70 to 29.70 °C, Colour (Platinum Cobalt Unit) ranged from 13 to 13850PCU in borehole water and leachate. The concentrations of, Lead, Chromium, Copper, Nitrate, Chlorine, Zinc and Iron ranged from; Lead 0.001 in BH 3 to 0.125 in BH 1, Copper 0.00 in BH 3 to 0.08 in BH 4, Chromium 0.014 in BH 3 to 0.037 in BH 2, Nitrate 234.2 in BH 4 to 343.0 in BH 1, Chlorine 0.35 in BH 3 to 1.71 in BH 4, Zinc; 0.09 mg/L in BH 3 to 0.25 in BH 4 and Iron 0.19 in BH 3 to 0.42 in BH 4 respectively. Alkalinity in water sample was below the WHO permissible limit. Arsenic and Iron were above the permissible limits in BH 1 (0.031 and 0.40 mg/L) and BH 4 (0.020 and 0.42 mg/L). Lead also exceeded the limit in BH 1 at 0.125 mg/L. DO, nitrate, nitrate-nitrogen and chlorine exceeded the limits across all the boreholes water sampled. In the microbiological analysis, Total Bacteria Count, E. coli, and Total Coliform Count were analyzed with mean values of 62.00, 6.50 and 23.75 respectively. All the microbial parameters analyzed exceeded WHO permissible limits which make the water unfit for direct consumption. The variations in concentration of microbiological parameters were in respect to distance from the dumpsite and elevation of the sampling points. There is therefore a need for major water treatment to be carried out on the borehole water before human consumption. Dumping of fresh refuse in the study area should be discouraged with the use of sanctions and fines on defaulters. Government should adopt eco-friendly solid waste disposal management systems such as sorting before disposal, incineration, landfill, waste conversion to biogas and compost as well as provision of portable water to reduce indiscriminate borehole construction to preserve the soil structure.