Pollution potential and causative hydrogeochemical processes in unconfined aquifer systems in a typical urban setting: emphasis on recharge and discharge areas

Abstract

The inhabitants of Akure Metropolis, southwestern Nigeria, depend solely on groundwater for their domestic, industrial and irrigation purposes. There is a need to delineate recharge and discharge areas for assessment and management of groundwater in these areas. One hundred and ninety (190) dug wells were selected for this assessment. Elevation and water table data aided accurate delineation of recharge, discharge and groundwater divide areas. Thirty-six wells representative of recharge and discharge areas were subjected to pollution assessment [DRASTIC, water quality index (WQI) and runoff potential]. The results revealed that the recharge areas have higher pollution potential and runoff amount than the discharge areas. This implied that groundwater sourced from recharge areas was more pollution prone than that sourced from discharge areas. WQI results revealed that the waters from recharge and discharge areas fall within excellent, good, poor, and unsuitable quality categories. Hydrogeochemical results revealed that concentrations of cations and anions are in order of Ca 2+ > Mg 2+ > K + > Na + and HCO 3 − > Cl − > SO 4 2− with a predominant Ca-HCO 3 facies typifying water from a basement complex environment. Gibbs plot and chloro-alkaline index affirmed the rock dominance and existence of imprints of ion-exchange processes influencing the groundwater quality. Intense weathering activities aided with long resident time spent by the water in the voids of the aquifer media are characteristic in this terrain. Recharge of precipitating water through infiltration into the weathered basement aquifers is a pointer to the greater yield of water in the wells. The possibility that precipitation-weathering process has led to the increase in concentrations of all ionic species and possible pollution of the groundwaters from the recharge and discharge areas cannot be ruled out at all.

Potential health risk and level of heavy metal in groundwater in the highly-dense area of Akure, Southwestern Nigeria

“…In other words, when one variable changed, another changed in a completely unrelated manner. This shows that human activity is the primary source of heavy metals in groundwater as well (Eyankware et Statistical approach to health risk assessment A sample of questionnaire was designed and administered to fty ve ( 55) persons to determine the potential health risk of water on the inhabitants of the area in the last ten (10) years. The result showed that certain percentage of the sampled people have suffered or experienced every common water borne diseases listed in the questionnaire, namely; diarrhea, typhoid fever, cholera, dysentery, hepatitis A and Giardia (Table 12).…”

Efficient adsorptive removal of paracetamol and thiazolyl blue from polluted water onto biosynthesized copper oxide nanoparticles

“…The use of contaminated water has had serious negative impacts on vegetation, people and other living things 6 . In developing nations, the local population's most dependable source of clean water, which is groundwater, is being rapidly polluted by industrial discharges of both organic and inorganic effluent 7 .…”

Adsorption mechanism and modeling of radionuclides and heavy metals onto ZnO nanoparticles: a review

“…The use of polluted waters has resulted in severe adverse effects on plants, humans, and living organisms in general (Ezemonye et al 2019;Lellis et al 2019). Groundwater which is the most reliable source of clean water for use by the local population in developing countries is rapidly being polluted from the agricultural application of pesticides and fertilizers, as well as from organic and inorganic effluent discharge from industries (Edokpayi et al 2018;Kiwaan et al 2020;Asiwaju-Bello et al 2020). In recent years, toxic pollutants were found to be present in unacceptable quantities in water in some developing countries, which poses a serious health threat to the local population (Ahmad and Danish 2018;Imran et al 2020).…”