Goronyo Dam is located across the Rima River at Goronyo (Latitude 13° 25' 56''E) in the Iullemmeden basin of Sokoto state, Northwest Nigeria. It has a storage capacity of 942 million cubic metres, mainly for water supply and irrigation to Sokoto and Birnin Kebbi states with population of over 8.5 million people. Recently, the water level in the dam has been reported to have depleted by 90% of its installed capacity, the worst since the construction of the dam over 30 years ago. Climate change with the shortage of rainfall in 2017 and the siltation of the dam has been attributed to this serious water level depletion. This has resulted to inadequate water supply to the Water Board that depends on water from the dam for water supply, irrigation, and other uses. The impact of the water shortage due to this climate change include dislocation of the socio-economic life of the people, families and livestock will be compelled to migrate thereby igniting socio tension and poor personal and communal hygiene with consequences of epidemics like cholera and dysentery etc. Construction of tube wells and effective management of water has been recommended to provide water supply to these communities until the rainfall situation improves.

An assessment of the groundwater quality and sanitation facilities in some selected schools in Potiskum was carried out. The study was aimed at determining both natural and anthropogenic effects on the physical, chemical and bacteriological composition that may affect the potability of groundwater in the schools. Geology and hydrogeology of the area was studied based on existing literature, water level in wells and boreholes were determined using dip meter. Thirty (30) schools were assessed comprising of twenty (20) primary schools generally with populations of over 2000 pupils and ten (10) secondary schools, two of which are boarding schools. 30 Water samples were taken from wells and boreholes in the schools, physical parameters were measured at the point of water sample collection while chemical analyses were carried out in the laboratory using colorimetry, titrimetry and flame photometry analytical procedures while bacteriological analysis was done using a microscope to count the coliform units. Potiskum is underlain by the Kerri-Kerri Formation and consist of grit, sandstone and clay. Water level ranges from 12 – 18 m, hand dug wells have an average depth range of 15 – 20 m while boreholes have a depth range of 45 – 100 m. The water has a mean temperature of 32°C, pH of 6.75 and Electrical Conductivity of 89.53 mS/cm. Chemical constituents that occur in higher concentration include sulphate (16.98 mg/l), chloride (15.7 mg/l), bicarbonate (15.06 mg/l) and calcium (9.11 mg/l). Trace elements that occur in higher concentration include copper (0.09 mg/l), iron (0.03 mg/l) and chromium (0.03 mg/l). The Piper plot revealed the dominant water type to be Calcium – Magnesium – Sulphate – Chloride water. The Durov and Gibbs plots indicated that hydrochemical process controlling the chemical composition of the water is simple dissolution or mixing. The water also has a high concentration of coliforms which may lead to gastrointestinal problems. Sanitary facilities seen in the selected schools are mainly Ventilated Improved Pit (VIP) latrines, ordinary pit latrines and pour-flush systems with average distance to water points of less than 20 m. This does not comply with the required standard. It could therefore be concluded from field observation of WASH facilities in selected schools in Potiskum that most of the water sources in these schools are in poor condition with the surrounding mostly unkept and wastewater flowing in dirty unplanned drains around the schools. Coliform bacteria are considered “indicator organisms”; their presence in the analysed water samples warns of the potential presence of disease-causing organisms and should alert the relevant authorities responsible for the water to take precautionary action.

Groundwater pollution status, related to heavy metal leachates from gold mine tailings, was investigated in Bariki and environs. It involved mapping rock outcrops, groundwater elevation, total dissolved solids (TDS), electrical conductance (EC), acidity – alkalinity level (pH), heavy metal concentration, and electrical resistivity sounding. Heavy metals’ composite contribution to pollution status was ascertained with metal pollution index (MPI). The rock outcrops are gneiss, schist, amphibolite, quartzite, and granite. The main TDS plume exists in vicinity of active mine site 6. Subsidiary plumes exist within neighbourhood of abandoned mine sites 1 and 2. The plume diminishes southward in direction of the groundwater flow. Highest EC value exists around main TDS plume. Other high TDS values occur around subsidiary plumes. The pH is lowest in vicinity of main plume. Highest pH value within lowest TDS area indicates regolith adsorption in an alkaline environment. Largest concentrations of Co (0.42 ppm), Cr (3.4 ppm), Cd (0.22 ppm) and Ni (0.7 ppm) associates with main TDS plume, highest EC, and lowest pH within neighbourhood of active mine 6. Very high concentrations of Cd and Ni also exist within neighbourhood of abandoned mine site 2. Regolith resistivity is lowest around mine sites 1, 2 and 6. It is highest within Latitudes N09° 29' 10" to N09° 29' 24" and Longitudes E06° 31' 30.0" to E06° 31' 48.0", where TDS and ionic concentration are lowest. This implies regolith resistivity is inversely related to TDS and ionic concentration. The groundwater overshot globally recommended concentration of Co, Cr, Cd and Ni in potable water. Computed MPI is 2.004, which indicates elevated heavy metal concentration. This reveals that the groundwater is polluted due to heavy metal leachates from mine tailings.

Evaluation of the solid waste disposal on the groundwater resources of Okene metropolis was carried out with the view of assessing the hydrochemical quality of the shallow groundwater system. The research methods applied involved field sampling and in situ measurements of physico-chemical parameters followed by hydrochemical analyses of the water samples. In situ measurements revealed Electrical conductivity (EC) value ranging from 2.00 to 1717.00μS/cm (average 688.04μS/cm) and the pH value ranged from 7.00 to 9.00 (average 7.37). Results of the study show that the cationic and anionic concentration varies as follows: Mg2+ ranges from 1.90 to 1532.29mg/l, (average 538.44 mg/l). Ca2+ ranges from 70.50 to 1540.00mg/l, (average 410.23mg/l) K+ ranges from 0.40 to 122.10mg/l, (average 20.9mg/l). Na+ ranges from 0.20 to 2.10mg/l, (average 0.76mg/l). Fe ranges from 0.00 to 0.35mg/l, (average 0.07mg/l). HCO3- ranges from 30.30 to 2010.00mg/l, (average 798.29mg/l) Cl- ranges from 3.00 to 176.40mg/l, (average 98.14mg/l). SO42- ranges from 0.80 to 42.10mg/l, (average 19.89mg/l). The study also reveals that the groundwater in areas where solid wastes are being dump, in most cases, is slightly alkaline (pH ranges from 7.00 to 9.00), slightly saline (TDS varies from 124.00 to 7839.00mg/l), and belongs to the following hydrochemical facies; Mg-Ca-HCO3, Mg – HCO3, Ca-Mg-HCO3, Ca- HCO3 and Ca-HCO3-Cl in order of increasing dominance. The abundance of chemical concentrations in groundwater within the study area is in order of Mg > Ca > K > Na for the major cations and HCO3 - > Cl > SO4 2- for the major anions. Statistical correlation reveals positive correlation between most of the parameters. Heavy metal parameters such as Cu, Pb, and others such as Cl, NO3, H2S in most of the sampled areas are above World Health Organisation, Nigeria Standard for Drinking Water Quality and European Union Standards for drinking water. Conclusively, Shallow Groundwater resources in the study area is considered to be unsafe for drinking purposes but can be considered excellent for irrigation with respect to Percentage sodium (Na%), sodium Adsorption ratio (SAR) and bicarbonate hazard.