Assessment of Groundwater Contamination Using the World Health Organisation Sanitary Risk Inspection Protocol in Urban Areas in Ghana

ABSTRACT

Introduction: In the last decade, there has been a significant increase in urbanisation with its attendant increase in demand for most social amenities including water. The relevant company is unable to meet the unending demand for pipe water. They are only capable of supplying intermittent and limited access to piped water especially in urban and peri-urban areas. These issues have caused most households in the urban and peri-urban areas to resort to the use of groundwater sources from wells and bore holes for their domestic activities. Although there are existing observational checklists for identifying potential contamination hazards around groundwater sources, these checklists were designed for rural rather than urban areas. It has therefore become necessary to update the checklist to include other contamination hazards peculiar to urban areas which are not in the existing checklist. Objective: To assess the replicability of an expanded sanitary risk inspection checklist for use in urban and peri- urban areas. Method: This was a cross sectional study carried out in urban and peri-urban communities in the Greater Accra region. The study sample of 62 wells were recruited after seeking approval from their owners. Structured questionnaire including the expanded sanitary risk inspection checklist was used to collect data on demographics, anthropogenic activities and possible hazards around the well. To evaluate the replicability of the updated checklist, two independent inspections were done in each household to identify the contamination hazards around urban and peri-urban groundwater sources concurrently. A sample of the well water in each household was taken for laboratory work to check for the presence of total aecal coliforms. Distribution of background characteristics are presented in frequencies, percentages, and averages. A binary logistic regression was used to test the association and effects of the possible hazards on the presence of total aecal xi coliforms. Area Under Receiver Operating Characteristic Curve (AUROC) was used to assess the model performance. Cohen Kapa test was used to test for agreement between responses of the two independent inspectors. Results: More than half of the wells were contaminated with total coliform and faecal coliforms (65% and 63% respectively). Among the hazards, holes in cement floors, ponding within 3m, waste floors, within 3m, polythene in blocked storm and the presence of algae in blocked drain were as significantly associated with the presence of Total coliform in and around water. The presence of faecal coliform was associated with rain prior to study day, faecal in blocked storm drain and the presence of blocked storm drain within 30 m of the well. Anthropological activities found to influence the presence of faecal coliform in groundwater were washing of clothes, washing of cars and farming around wells while none of the human activities has any relationship with presence of total coliform. Replicability results have shown that there is a very high level of agreement between independent by different individuals working in the same locations. Conclusion: Most of the groundwater sources in urban and peri-urban areas are contaminated according to the World Health Organisation (WHO) standards. Anthropogenic activities around the wells contributed to the contamination of the groundwater. The level of replicability among the inspectors indicates that it is possible to expand the inspection checklist to include the urban and peri-urban hazards.