Research Journal of Applied Sciences, Engineering and Technology 2(1): 39-44, 2010 ISSN: 2040-7467 © Maxwell Scientific Organization, 2009 Submitted Date: September 18, 2009 Accepted Date: October 08, 2009 Published Date: January 05, 2010 Corresponding Author: E.O. Longe, Department of Civil and Environmental Engineering University of Lagos, Akoka, Yaba, Lagos, Nigeria 39 Groundwater Quality Assessment near a Municipal Landfill, Lagos, Nigeria E.O. Longe and M.R. Balogun Department of Civil and Environmental Engineering, University of Lagos, Akoka, Yaba, Lagos, Nigeria. Abstract: The current research examined the level of groundwater contamination near a municipal landfill site in Alimosho Local Government Area of Lagos State, Nigeria. Water quality parameters (physico-chemical and heavy metals) of leachate and groundwater samples were analyzed. The mean concentrations of all measured parameters except NO 3 G, PO 4 + and CrG conform to the stipulated World Health Organization potable water standards and the Nigerian Standard for Drinking Water Quality. Mean concentration values for TDS, DO, NH 4 + , SO 4 + , PO 4 + , NO 3 G and ClG are 9.17 mg L G 1 , 3.19 mg LG 1 , 0.22 mg L G 1 , 1.60 mg LG 1 , 10.73 mg LG 1 , 38.5 mg LG 1 and 7.80 mg LG 1 respectively. The mean concentration values for Fe, Mn, Zn and Cr - in groundwater samples are 0.07mg L G 1 , 0.08mg LG 1 , 0.08mg LG 1 and 0.44mg LG 1 respectively. The current results show insignificant impact of the landfill operations on the groundwater resource. The existing soil stratigraphy at the landfill site consisting of clay and silty clay is deduced to have significantly influenced natural attenuation of leachate into the groundwater resource. It is however observed that in the absence of a properly designed leachate collection system, uncontrolled accumulation of leachates at the base of the landfill pose potential contamination risk to groundwater resource in the very near future. The research recommends an upgrade of the solous landfill to a standard that would guarantee adequate protection of both the surface and the groundwater resources in the locality. Key words: Contamination, groundwater, leachate, municipal, quality and stratigraphy. INTRODUCTION The intensity of man’s activities has led to increasing volume of solid waste worldwide despite the current level of technological advancement and industrialization. Explosive population growth is one other major factor responsible for increased municipal solid waste (MSW). Land filling of municipal solid waste is a common waste management practice and one of the cheapest methods for organized waste management in many parts of the world (El-Fadel et al., 1997; Dsakalopoulous et al., 1998, Jhamnani et al., 2009). In most low to medium income developing nations, almost 100 per cent of MSW generated goes to landfills. Landfill operations are most feasible in these countries as land is vastly available and moderately inexpensive. Even in many developed countries where land is scarce and where policies of reduction, reuse and diversion from landfills are strongly promoted, great percentage of their generated MSW are still land filled. For instance, in 2006, out of the 251 million tons of MSW generated in the United States of America, 138.2 million tons representing 55% was disposed of in landfills (USEPA, 2007). In England, out of the 29.1million tons of municipal solid waste generated between 2003 and 2004, 72% was land filled (DEFRA, 2005). The scenario is similar in Northern Ireland and Scotland where82.9% and 85.4% of their generated MSW were land filled in 2005 and 2007 respectively (EHS, 2005; SEPA, 2007). Today, however, there is a progressive decrease in the volume of MSW being land filled in these developed countries on a yearly basis as great efforts in solid waste management are today directed towards waste reduction and recycling programmes which is a real giant step in environmental improvements (USEPA, 2007, 2008). Landfills may however pose serious threat to the quality of the environment if incorrectly secured and improperly operated. The threat to surface and ground waters could be deleterious. The scale of this threat depends on the composition and quantity of leachate and the distance of a landfill from water sources (Slomczynska and Slomczynski, 2004). Municipal landfill leachate are highly concentrated complex effluents which contain dissolved organic matters; inorganic compounds, such as ammonium, calcium, magnesium, sodium, potassium, iron, sulphates, chlorides and heavy metals such as cadmium, chromium, copper, lead, nickel, zinc; and xenobiotic organic substances (Lee and Jones-Lee, 1993; Christensen et al., 2001; Tengrui et al., 2007; Ogundiran and Afolabi, 2008). The rate and characteristics of leachate production depends on a number of factors such as solid waste composition, particle size, degree of compaction, hydrology of site, age of landfill, moisture and temperature conditions, and