Subsurface Contamination In The Vadose Zone By Leachate At Four Open Refuse Dumps In Maiduguri, North East Nigeria
The paper investigates the behaviour of four parameters namely chloride, sodium, potassium and nitrate underneath open dumps in an arid environment. Four sites were chosen for the study. These are University of Maiduguri (Unimaid), Lamisula, Wulari and the Kasuwa Shanu (Cattle Market) refuse dump sites. The first three are domestic solid waste dumps while the latter is an animal market waste dump. Soil samples were collected from these four dump sites. From each site was taken background sample at depths of 0.01m. All the parameters were detectable at all sites understudied at this depth. Chloride showed the clearest and most consistent behaviour at the four sites for the parameters tested. The consistency of chloride qualified it to be used a base for consideration to establish any other consistent parameter. Chloride and/or sodium can be used as conservative tracers in the vadose zone of the arid region to monitor the movement of leachate to protect the ground water system. The natural soil studied exhibited attenuation properties.