Physico-Chemical Quality of Groundwater in Keta South, Ghana

Abstract

Abstract:The paper investigated physico-chemical quality of groundwater, considering the relative proximity of hand dug wells to coastal environment, but most importantly close to insanitary facilities like refuse dumps, septic tanks and pit latrines; this was done in selected coastal communities in the Keta. Thirty vials of water samples from selected hand dug wells in two seasons were tested for pH, Total Dissolved Solids (TDS), Conductivity, Turbidity, Calcium, Magnesium, Nitrate, Sulphate, and Phosphate; WHO standards of drinking water were adopted to validate the results obtained and statistical analysis run. Statistical analysis of results showed a statistical significance in Turbidity, Nitrate, Phosphate, Calcium and Magnesium values at p<0.05, between the two seasons. There was a weak but significant correlation between Calcium and distance (r=0.398) and a strong correlation between Magnesium and distance (r=0.763). The study revealed that all the hand dug wells sampled recorded relatively high concentration of conductivity, turbidity, TDS, Calcium, Magnesium and Phosphates, irrespective of their proximity to the insanitary facilities and coastal environment, apart from nitrates when compared to WHO standards of drinking water.

Groundwater in the coastal areas of Ghana: Quality and associated health risks

“…We attribute the brackish nature of water to the influence of the sea through seawater intrusion and/or deposition of atmospheric sea aerosol, dissolution of minerals and infiltrating wastewater in the neighborhood of the wells. Similar to our findings for Accra and Winneba, another study [ 23 ] reported higher values of EC/TDS in the wet season compared to the dry season in their work in the Keta area. It is difficult to explain the observed higher EC/salinity values in the rainy season compared to the dry season for Accra and Winneba; it is common for the vice versa to be observed and usually attributed to dilution in concentrations of chemicals and other physical water quality parameters during the wet season and evaporation in the dry season increasing concentrations of chemical parameters and physical quality values.…”

“…For example, the Keta area is made up of unconsolidated sediments with a high possibility of entrainment of these loosely held sediments into flowing water during the wet season. A study in the Keta area made similar findings [ 23 ]. The high turbidity recorded in wells in Accra during the dry season cannot be explained, we speculate the possible seepage of wastewater into the shallow groundwater system of the area.…”

“…Furthermore, suspended particles can provide attachment for heavy metals. High turbidity values for the other three communities during the rainy season may be as a result of two possibilities: (1) direct inflow of run-off water into especially large diameter hand dug wells that lacks protective apron walls which was a common observation in the Keta area (note that the Keta area is known to experience seasonal flooding [ 23 ] and therefore compliments the assertion that run-off may flow directly into some of the wells); and/or (2) rapid changes in hydrodynamic conditions within the aquifer in the neighborhood of the wells and boreholes during the rainy season. Increased groundwater flow rates can result in dislodging of sediments from the surfaces of aquifer media and re-suspension of these sediments together with quartz colloids in water within groundwater flow lines.…”

“…Despite these shortfalls, not much have been done to fully assess the quality of self-supply water sources in the coastal areas of Ghana. Most work on the subject is limited to small communities and, in rare cases, districts and regions [ [23] , [24] , [25] , [26] , [27] , [28] ]. There is currently no broad assessment of groundwater that encompasses the entire coastal areas of Ghana.…”