Physicochemical Characteristics of Groundwater Samples and Leachate from Gbagede Dumpsite, Amoyo, Kwara State, Nigeria

Yakubu, M.T. and Omar, S.A.

Abstract

This study determined the physicochemical properties of groundwater and leachate samples obtained from
dumpsite at Gbagede, Amoyo in Kwara State, Nigeria. Water samples collected from two wells located at a distance
of 15 m and 150 m from the dumpsite and leachate at Gbagede were analyzed for physical and chemical properties
using standard methods. The turbidity of the groundwater samples (GW1 and GW2) and leachate was higher than
the World Health Organization (WHO) Standard and Nigeria Standard Drink and Quality Water (NSDWQ)
(Reference Standards). The conductivity, nitrate, nitrite, chloride, sulphate, dissolved oxygen, biochemical oxygen
demand, zinc, copper, aluminum and nickel of the three samples were generally lower than the Reference Standards
while the total suspended solids was barely detected. The pH of the GW1 sample was within the Reference
Standards whereas that of GW2 and leachate samples were higher than the WHO and NSDQW standards. The
alkalinity of GW1 and GW2 was lower than the Reference Standards whereas that of leachate was higher than
Reference Standards. Phosphate levels in the groundwater samples were lower whereas in the leachate, it was higher
than the Reference Standards. The chemical oxygen demand was lower in GW1 and GW2 whereas it was higher
than the WHO recommended limit in the leachates. Lead content in GW1 and GW2 was lower whereas in the
leachate, it was higher than WHO standard. The cadmium content in GW1 was within the Reference Standards;
cadmium content in GW2 was lower than that of the Reference Standards whereas it was higher than the Reference
Standards in the leachates. In conclusion, the open dumpsite at Gbagede have minimally impacted (5% of the
physicochemical characteristics exceeded the reference limit) on the physicochemical characteristics of the ground
water whereas the dumpsite had more impact (53% of the physiochemical characteristics) on the physiochemical
characteristics of the leachate.