Investigating Anthropogenic Impact On Groundwater Quality In The Ga East Municipality

ABSTRACT

Population growth and industrialisation have put a lot of pressure on water resources the world over. Accra is overpopulated due to influx of people from other part of the country to seek greener pastures with limited access to water supply from the Ghana Water Company Limited (GWCL) resulting in individuals supplying their own water through drilling of individual boreholes. Hydrochemical data from 39 water samples (i.e. boreholes, hand dug wells and surface water) from six communities within the Ga East Municipal Assembly were sampled and analysed for various physico-chemical water quality parameters including trace or heavy element and microbiological quality parameters using appropriate certified and acceptable international procedures in order to assess the sources and contamination of water types as well as their suitability of groundwater within the study area for drinking and irrigation purposes. Generally, groundwater in the study area is slightly acidic and slightly alkaline but majority of samples are within the World Health Organisation guideline for domestic use with samples dominated by Na ions over all other cations. From the Principal component analysis (PCA) model, it is clear that PC 1 represented rock/mineral weathering, PC2 represents contamination from agricultural waste and PC3 represents effluent from dumpsites. A Gibbbs diagram supporting the PCA also revealed that rock weathering and evaporation were the major hydrogeochemical process regulating the water chemistry of the study area. From the Piper plot, 3 facies of groundwater were obtained namely Na-Cl, Na-HCO3- and HCO3-Cl. Microbial analysis revealed that almost all samples analysed were bacteriologically contaminated since Total Counts and E.Coli bacteria were high this suggested that contamination was from faecal matter as a result from human activity. The study revealed that in all three types of water sampled, surface water registered the

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highest Coliform Counts followed by hand dug wells and lastly boreholes. From the Human Health Risk Analysis, 35% of borehole samples pose health risk to users since their Hazard Quotient and Hazard Index were higher than 1 especially for Pb, Cd and Mn in some sampling sites. The study also revealed that children mostly stand a high risk of health problems associated with consumption of theses heavy metals in the water samples. The research showed that human activities that might be compromising the groundwater quality in the Municipality were improper disposal of waste, drilling boreholes near crack septic tanks as a results of limited space, effluents from soak aways, runoff from irrigation sites, car washing bays, auto-mechanic shops, humans and animals waste in the various communities as a result of open defaecation etc. with poor sanitation been the highest culprit.