IMMINENT THREATS TO GROUNDWATER RESOURCES DUE TO UNCONTROLLED LANDFILLING

IMMINENT THREATS TO GROUNDWATER RESOURCES DUE TO UNCONTROLLED LANDFILLING

CHAPTER ONE

INTRODUCTION

1.1     BACKGROUND OF THE STUDY

The practices of solid waste management (SWM) and solid waste disposal (SWD) in Kano metropolis, Nigeria, were examined. The water quality of groundwater sources in the areas adjacent to the SWD sites was monitored in order to evaluate interactions and assess the possibility of groundwater contamination as a result of percolation of the leachates generated in the SWD sites. An integrated approach to the field investigation was employed in the study. This included an extensive desk study; a field survey of all existing SWD sites in the area; leachate and groundwater sampling; and laboratory-based experimental and instrumental analyses. The locations of the SWD sites relative to inhabited areas were examined, and eight sites and their environs were selected for leachate and groundwater sampling and quality assessments in May 2009 and May 2010. It was observed that SWM activities in Kano metropolis are unsystematic and pose a significant risk to both public health and environmental quality, especially in relation to local groundwater sources. It was also found that the leachates produced in the sampled sites contained significant concentrations of a wide range of contaminants; including nitrates, total alkalinity, total dissolved solids, chlorides and sulphates. The leachates were also observed to be in the methanogenic phase of biochemical degradation and were shown to have similar characteristics to other leachates from mature SWD sites in different parts of the world. Similarly, the physico-chemical characteristics of the groundwater samples around the selected SWD sites indicated high concentrations of nitrates, chlorides, total dissolved solids, total alkalinity, turbidity, iron and manganese, often above the WHO thresholds for acceptable drinking water quality. It is, therefore, concluded that the shallow groundwater sources analysed have been contaminated, due largely to improper SWM practice. This, in turn, affects not only the health and well-being of the local population, but also impedes developmental efforts and obstructs prosperity. Accordingly, some strategies for pollution prevention and control were developed for Kano metropolis, although they are also applicable to other urban areas with similar characteristics. These strategies, which are largely categorized as resource focused, source-focused or remedial measures, can be achieved through: (1) identification and mapping of pollution sources; (2) establishment of databases and information management system; (3) vulnerability mapping; (4) establishment of functional monitoring and evaluation system; (5) promotion of public awareness and participation; (6) establishment of protection zones; and (7) the integration of pollution prevention and control strategy into urban planning, development and management of municipal services.