Hydrochemical characterization of abandoned quarry and mine water for domestic and irrigation uses in Abakaliki, southeast Nigeria

Abstract

The Abakaliki area has been renowned for lead–zinc mining and hard rock quarrying, and these activities generate acid mine drainages (AMDs) and chemical dissolution of minerals into the water, respectively. This research is aimed at assessing the influence of AMDs and other dissolved elements on water quality for domestic and irrigation uses in the area. Thirty-five water samples were collected and analyzed for physicochemical parameters, including: pH, total dissolved solid, electrical conductivity, major cation and anion and heavy metals using atomic absorption spectrophotometric methods. Mathematical calculations were used to deduce irrigation parameters. Result indicates that pH of water samples is slightly basic to acidic, and EC ranges from 5.28 to 1492 µS/cm. Only samples around Nigercem, Nkalagu and lead–zinc mines at Enyigba were above WHO permissible limit for drinking water. The concentrations of Na+, K+, Ca2+, Mg2+ and HCO3− were within WHO set standard for drinking water, while Cl− and SO42− were above the WHO set standard. Irrigation parameters showed soluble sodium percentage between 8.33 and 100.00, sodium percentage ranges between 2.77 and 300.00%, Kelly ratio ranges from 0.03 to 3.00, magnesium absorption ratio ranges between 16. 92 and 123.5, total hardness ranges between 3.00 and 125.0, residual sodium bicarbonate ranges between − 23.84 and 0.11, and potential salinity ranges from 2.93 to 14.77 within the study area. Abandoned mine water in the area is fairly suitable for irrigation uses, but unsuitable for domestic uses. This is due to high chemical activities taking place in the mine ponds, and these 17 ponds have been abandoned for over 2 decades. Deductions from Soltan classification revealed that 98% of groundwater falls within deep meteoric water.