The project area, Enugu and environs, is defined by Latitudes 60 14' 15" to 60 31' 20" North of the Equator and Longitudes 70 22' to 70 35' 20" East of the Greenwich Meridian. It covers towns and villages such as Ngwo - Enugu, Ukana, Oriemba and Ninth Mile Corner with Enugu urban at the Centre.\r\nThe cuesta is the dominant physiographic feature that trends North-South west of Enugu town. It acts as water divide for groundwater and surface water between the Anambra Basin to the west and the Cross River Basin to the east. The project area falls within the Anambra Basin and is geologically underlain by Agbani Sandstone, Enugu Shales, Mamu, Ajali and Nsukka .Physico-chemical interpretation of groundwater in Enugu

Physico-chemical interpretation of groundwater in Onitsha

The study area lies between latitudes 100 26' to 100 40'N and longitudes 70 19' to 70 33'E with a total surface area of 630km2. The major town in the study area is Kaduna, which is the capital of Kaduna State.\r\n\r\nThe area is underlain by the Nigerian Basement Complex. The dominant rock types are the migmatite-gneiss complex and the Older Granites, which intruded the host gneissic rocks. Prolonged in-situ weathering of the crystalline Basement Complex rocks under tropical conditions has produced a sequence of unconsolidated material (laterites) whose thickness and lateral extent vary extensively. \r\n\r\nThere are three major aquifers in the study area namely weathered overburden aquifer, fractured bedrock aquifer and the stream alluvial deposits aquifer. The three aquifers are interconnected and form one hydraulic system with unconfined water table. \r\n\r\nEighty-eight (88) hand-dug wells, with depths ranging from 0.2 to 11.6m, were studied and thirty-four (34) representative water samples were analyzed in the laboratory. The results were compared with WHO (2006) and NAFDAC standards for drinking water. \r\n\r\nResults of physical parameters showed pH ranged from 4.83 to 7.80, electrical conductivity from 20-980µS/cm and TDS from 10-490mg/l. Results of the cations showed Na+ varied from 1.66-221.20mg/l, Ca2+ from 0.23-92.00mg/l, Mg2+ from 0.12-154.00mg/l, K+ from 0.72-71.48mg/l, Fe2+ from 0.02mg/-0.22mg/l and Pb2+ from 0.18-0.95 mg/l. Results of the anions showed Cl- ranged from 2.67-176.94 mg/l, SO42- from 1.00-250 mg/l, NO3-from 0.05-55.00mg/l ,CO32- from 4.80-50.40mg/l and HCO3- from 2.40-62.00mg/l. Result of the microbial analysis showed Cfu/ml varied from 80-240. The concentration values of the cations and anions (except Fe2+ and SO42-) exceeded the WHO (2006) and NAFDAC recommended limits for drinking water in some places. The dominant cation and anion in the groundwater are magnesium and chloride respectively. The water types are Mg-Cl, Ca-Mg-SO4 and Na- K waters. \r\nThe high concentration of sodium and chloride in the water samples from some places in the study area could be from contamination by saline effluents or leachates from waste dumps. The relative high concentration of nitrate in the study area could be as a result of pollution from septic tanks. \r\nWaste dumps of serious environmental concern were observed at Fire Brigade, Tudun Nupewa, Tudun Wada, Hayin Banki, Ungwan Dossa, and Kawo. Kaduna River around the factories at Kakuri and downstream of River Kaduna are polluted with industrial waste. \r\nIt is recommended that the factories located in Kaduna South should process their industrial wastes before discharging them into the river. In addition, the water from hand-dug wells in the area should be treated before drinking.\r\n

Hydrogeology, geology and geophysics were used to study the groundwater potentials of Ibadan and its environs. These potentials include quantity, quality and availability of groundwater to the masses of the people. Due to the factor of affordability, hand dug wells are more in use than deep bore holes which are exclusively for the rich. \r\n\r\nRecords from 690 sample points such as wells, bore holes, streams and the results from ninety-three (93) analyzed water samples form the basis of conclusion and recommendations in this report.\r\n\r\nChemical analysis shows HCO3+CO3 dominated water with low to medium salinity hazard. Nitrate is too low there by allaying the fear of present level of contamination. \r\n\r\nIncident of groundwater contamination by leachates could be a problem in the immediate future because of indiscriminate dumping of solid wastes in unauthorized locations and river system. Lowering of groundwater level due to over extraction should be prevented with appropriate laws. The quality of water is fair as more than half of respondents claim they only use the water for domestic chores except drinking. Microbial contamination is average as most wells lack proper hygiene. \r\n\r\nContinuous monitoring and education is necessary to safe guard the groundwater resources of Ibadan and environs.\r\n

The study area, Uyo and its environs, is located in Akwa Ibom State, south-southern Nigeria and is bounded by latitudes 04° 56' 00" to 05° 07' 30"N and longitudes 007° 49' 30" to 008° 2' 00"E with an areal extent of 625km2 and is made up of extracts of 1:50,000 Sheets Ikot Ekpene, Uwet, Opobo and Calabar; namely, 331NW, 330NE, 323SW and 322SE. The Local Government Areas covered in the course of this study are Ibiono Ibom LGA, Ikono LGA, Itu LGA, Uruan LGA as well as Uyo LGA. \r\n\r\nThe objective of the project was to determine the distribution of physicochemical parameters and microbial loads in the water, which will be useful for the planning and sustainable management of surface and groundwater resources in the area.\r\n\r\nThe methods adopted for the project were geological mapping, geophysical studies, hydrogeological and hydrochemical mapping as well as hydraulic conductivity determination of the soil media within the study area. The hydrochemical and hydraulic conductivity were determined after conducting laboratory analyses on water and soil samples following standard laboratory procedures.\r\n\r\nThe study area is underlain by Tertiary to Recent continental fluviatile sands and clays of Benin Formation, also known as Coastal Plain sands. Geologically, the study area is composed of coastal sediments of sands/sandy clay, clayey sand, pebbly, clayey sand and minor clay. Conglomeratic bands occur at various horizons within the section (as shown in Plate 1). The sediments reflect continental environment of deposition. The rock units are generally porous, poorly sorted, loose and friable. The loose and friable nature of the upper part of the formation gave rise to gully erosion at various parts of the study area.\r\n\r\nFour main hydro-stratigraphic units were delineated within Uyo based on stratigraphic relation and lithology. These include upper, middle and lower sand aquifers, in increasing geologic age and depth of burial with the Imo shale aquitard separating the most extensive middle aquifer from the lower sand aquifer. The upper sand aquifer of the recent alluvium deposits and Pleistocene-Pliocene Benin Formation form the major aquiferous units in the study area. The deposits include lateritic sands, fine to medium-grained sands and dark grey carbonaceous muds.\r\n\r\nThe highest water elevation of 92m was recorded in the northern portion of the study area while the lowest elevation of -66m (66m below mean sea level) was recorded in the south. In the study area, the Groundwater flow displays a general north - south and easterly direction which is attributable the subsurface basins in the south and east respectively and likely responsible to the presence of swampy flood plain east of the study area. Hydrogeologically, widely spaced contour areas, as observed in Uyo and its environs, are very prolific in groundwater yield.\r\n\r\nThe water samples are predominantly earth-alkaline water species (Ca2+ and Mg2+) with predominantly Cl- and HCO3-. Analysis revealed that the relative abundance of the major cations is as such: Ca > Mg > Na+K, with the Ca being the most dominant cation in all the water samples analyzed. While the relative abundance of the major anions for the water samples is as such: Cl > HCO3 > SO4, with Cl being the most dominant anion.\r\n\r\nAccording the classification of Permeability based on Terzaghi and Peck (1967), the permeability of the soils in the study area ranged from Low Permeability to Medium Permeability, with Low Permeability being restricted to the eastern flank of the study area where the swamp exists, and which is characterized by clayey sand.\r\n\r\nGeophysical investigation using the electrical method (Vertical Electrical Sounding) revealed that the study area generally has fair to good groundwater yield, which can be tapped through borehole drilling predominantly for domestic and small-scale industrial uses. These aquifers are thin and are mainly recharged by precipitation, hence, may not support heavy industrial water needs. It is therefore paramount to probe in excess of 500m depth for probable high yield aquifers for such industrial use. The geophysical survey also revealed the presence of a deep-seated incision trending approximately north - south across the entire study area.\r\n\r\nThe physical and chemical parameters of the water samples conformed to international standards of potable water except for a few water samples having concentrations of certain constituents exceeding the WHO and NSDWQ maximum permissible limits in drinking water, which rendered the water in those localities unfit for human consumption unless treated. \r\n

Effect of rock-water interactions in Calabar area

The study area, Katsina town and its environs, is located in Katsina State, northwestern Nigeria. It is defined by longitudes 7° 30'E to 7° 45'E and latitudes 12° 52' 10"N to 13° 07' 10"N with a total area of 625km2.\r\n\r\nThe objective of the project was to study the hydrogeochemical characteristics of water in the area and the impact of waste dumps on the water quality. The methods adopted for the project were geological mapping, geophysical studies, hydrogeological mapping and waste management assessment coupled with laboratory analyses of water and soil samples.\r\n\r\nThe area is underlain by both Crystalline Basement rocks and sedimentary rocks and it lies at the eastern periphery of the Iullemmeden (Sokoto) Basin. The conglomeratic sandstone of Gundumi formation constitute the aquifer in the sedimentary area while the weathered overburden, fractured and jointed zones constitute the aquifers in the basement underlain areas as revealed by geophysical studies.\r\n\r\nThe water type in the project area is earth-alkaline (calcium and magnesium) and predominantly chloride (Cl-) and bicarbonate (HCO3-) water species.\r\n\r\nThere is no officially-designated waste dumpsite(s) in the project area, which resulted in indiscriminate dumping of wastes in unapproved sites such as road sides, drains, streams and river channels. Handdug wells, hand pump boreholes and deep boreholes are located indiscriminately close to dumpsites, latrines, septic tanks and drains.\r\n\r\nThe physical and chemical parameters of the water samples particularly those of the groundwater conformed with international standards of potable water except groundwater in the vicinity of dumpsites, that had electrical conductivity, total dissolved solids, nitrate, chloride and Coliform Counts exceeding the WHO and SON maximum permissible limits in drinking water, which rendered the water unfit for human consumption, unless treated.\r\n\r\n\r\n

The study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\nThe study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\nThe study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.The Federal Government of Nigeria should formulate a stringent regulation to force the states Governments to always design, construct and monitor landfills in their states and also to force their people to take the refuse collected to the designated landfills.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\nThe study area is between Latitudes 080 46' - 090 00'E and Longitudes 090 48' - 10 02'N and covers an area of about 635km2. The area covers about 5 local governments: Jos North, Jos South, Jos East, Bassa and some parts of Toro Local Government in Bauchi state. \r\n\r\nThe topography of the area is virtually undulating. The undulations are due to the rocky nature of the terrain and several water paths that follow the basement structure. The area is covered with high relief older granite plutons and younger granite ring complexes.\r\n\r\nThe geology of this area can be divided into six major lithological groups: (i) the precambrian migmatites and granite gneisses of the basement complex covering an area of about 97km2 (i.e. 15%) in the Central and Northern parts of the map; (ii) the pan-African older granites comprising of coarse porphyritic biotite and biotite hornblende granite and fine grained biotite granite occupying an area of about 83km2 (i.e. 13%) in the Western margin and Central part of the map; (iii) the Jurassic younger granite series comprising of granite and porphyries occupying an area of about 349km2 (i.e. 55%) in the Central, South East, North West and North Eastern parts of the map; (iv) the late cretaceous older basalts occupying an area of about 25km2 (i.e. 4%) in the South-Western and North Western parts of the map (v) the late tertiary/quartenary newer basalts occupying an area of about 36km2 (i.e. 10%) in the Central part of the map; and (vi) the Neogene sediments (Alluvium) occupying an area of about 25km2 (i.e. 4%) along the rivers in the entire area.\r\n\r\nStreams, rivers, springs and mining ponds provide the surface water resources of the area. The major Rivers in the area are River Bauna, River Dilimi, River Tilden Fulani, River Rukuba, River Gell and Shen River. The drainage pattern of all the rivers and streams in the area is controlled by chains of mountains and hills of high relief on the Jos Plateau. \r\n \r\nGroundwater in this area occurs in 4 different aquifer types: (i) the weathered or overburden or regolith aquifer (ii) the fractured basement rock aquifer (iii) the alluvium aquifer and (iv) the fluvio-volcanic aquifer. The overburden or regolith aquifer is the main aquifer in the study area which provides water to about 95% of the population via hand-dug wells. The aquifer is unconfined. It is discontinuous due to the rocky nature of the area. It is generally clayey. It is porous but not very permeable. The water table ranges from less than 3m in the rainy season to a maximum of 10m in the dry season. The younger granite in the study area is characterized by a pronounced set of open joints which show a persistent northerly trend and contain a lot of water. As a result shallow ground water occurs almost every where in the decomposed zone (regolith aquifer) overlying the fresh rock. This is extremely developed for domestic purposes by means of numerous hand-dug wells.\r\n\r\nThe electrical resistivity survey carried out at 16 locations in the area shows that the basement rocks of Jos appear to be highly weathered and fractured hence, the area has high water potential. The survey also shows that the depth to the probable aquiferous layer varies between 9.4m and 42. 5m. Since the basement in the study area is shallow and in most cases fractured, contaminants/leachates could easily find their way to pollute the ground water. \r\n\r\nThe waters in the wells and streams of Jos town and its surroundings villages are dominantly calcium bicarbonate (Ca-HCO3) and sodium chloride bicarbonate (Na-Cl-HCO3) waters. This is because of the dominance of Ca++, Cl-, Na+ and HCO3- ions in the waters. \r\n\r\nThe regolith aquifers in the surrounding villages and some parts of Jos town (like the G. R. A and millionaires quarters) show relatively low mineral content (TDS of 4.83 to 169 ppm) while concentrations in excess of 958 ppm occur within the congested parts of Jos town where land surface derived wastes contribute to the excess. \r\n\r\n94% of the water samples are slightly acidic with the pH range of 5.1 - 6.9 while 6% of samples are slightly alkaline with the pH range of 7.1 - 8.8. The moderately low pH values (i.e. 5.1 - 6.9) or the slightly acidic nature of the samples may be due to the clay rich nature of the overburden weathered sediments of the basement rocks. The pH values of water samples in the study area (i.e. 5.1 - 7.88) have nearly fallen within the permissible range for drinking water recommended by WHO, NAFDAC and NPDWR (USA) which are 7.0 - 8.5, 6.5 - 8.5 and 6.5 - 8.5 respectively. Therefore, in terms of pH, the waters in the regolith aquifers in the study area are good for drinking, washing and cooking. \r\n\r\nThe amount of all the cations and anions present in the waters of all the hand-dug wells and streams studied cannot pose any problem, as regards drinking washing, bathing and other domestic uses when compared with the WHO, NAFDAC and NPDWR (USA) standards for drinking water. The waters are also free from deleterious metals like copper and arsenic. The waters that contain high total dissolved solids in the study area were found to contain a lot chloride and nitrate. The chloride is in excess of 172 mg/liter at location 282 (Dodo Street) and the Nitrate is in excess of 43 mg/liter at location 289 (Abba Na Shehu Street). This is due to the leachates from the numerous waste dumps around as confirmed by the medium permeability of the 4 soil samples collected from the bottoms of 4 refuse dumps in this area. The presence of nitrates in all the samples is a sign of pollution from inorganic wastes and fertilizers used in the farms.\r\n\r\nGenerally, the levels of faecal pollution in the well waters of Jos town and the surrounding villages are high. This could be connected to the (i) siting of wells near pit latrines or septic tanks or refuse damps; (ii) using contaminated containers to fetch water; (iii) throwing of containers used for fetching water on the ground near the wells when not in use; (iv) washing dishes near the wells (v) leaving the wells open when not in use; (v) presence of animals and chickens near the well.\r\n

The study area covers Ilesha and its environs in Osun State, south-western Nigeria. It is defined by latitudes 7°31' to 7° 44' N and longitudes 4° 37' to 4° 51'E and falls within 1:100,000 Sheet 243 Ilesha and covers an area of 625km2.\r\n\r\nThe objective of the project area is to study the hydrogeological characteristics of the area and the impact of waste dumps on the water quality.\r\n\r\nThe methods adopted were geological mapping, geophysical studies, hydrogeological mapping and laboratory analyses of water and soil samples.\r\n\r\nThe rock types in the area in order of abundance are mica schist, quartzite/quartz schist and granite gneiss within these rocks are intrusions of pegmatite and quartz veins.\r\n\r\nThere are peculiar wells that were dry during raining season and have water during the dry season. The clayey nature of the overburden was adduced to have caused delayed recharge of the aquifer due to the low permeability of the overburden materials.\r\n\r\nThe results showed that the waste dumps in the project area have affected the water quality. This is induced by the high nitrate content, high coliform counts and high proportions of trace elements like Iron (Fe), Copper (Cu), Chromium (Cr), Lead (Pb), Nickel (Ni), Cadmium (Cd) and Arsenic (As) which have values that exceed the World Health Organization (W.H.O.) recommended limits. All these are indicators that both the surface and ground waters in the area are polluted (contaminated).\r\n\r\nThe concerned authorities should as a matter of urgency embark on the supply of potable water to the people of Ilesha and environs.\r\n

The effects of waste dumps on the groundwater supply in Kano and the environs are being investigated. Water samples were collected from the ubiquitous hand-dug wells which form the major source of water supply to the Kano populace, as 96 of the samples were analyzed for their cation and anion contents. \r\n\r\nThe chemical analyses revealed the presence of Ca2+, Mg2+, Na+, K+, Fe2+ , etc. as cations while anions include: HCO3-, Cl-, SO42-, NO3-. The chemical analyses also showed that the groundwater is polluted by leachates from the waste dumps because the values of total dissolved solids, conductivity and salinity were very high in wells near the dumpsites. For instance, at the Court Road dumpsite in Kano metropolis, the total dissolved solids in the wells near it were 983mg/l, conductivity 2000 microsiemens and pH 7.8, while at Yanlemu dumpsite, the total dissolved solids was 1240mg/l conductivity 2520 microsiemens and a high chlorine content of 16.2mg/l. The pH ranged from 5.57 to 7.60 though with most values between 6.0-7.0.\r\n\r\nMicrobial analyses showed that the wells are polluted by micro-organisms like Escherichia coli that could cause epidemic of cholera and such gastrointestinal diseases.\r\n\r\nThe Vertical Electrical Sounding (VES) was used to complement the hydrogeological mapping. A total of 24 VES points were chosen based on different lithologies. It was deduced by the VES that the depths of the topsoil (mainly laterites) to the weathered basement, which is the aquifer, varied from 0.4 - 13.1metres. \r\n\r\n\r\nSieve analysis was performed to further complement the study of the groundwater infiltration. The silty, medium and coarse gravels permit passage of rainwater into the vadose zones and thence to the water-table.\r\n\r\nThe state government could reduce reliance on wells especially for domestic use by providing adequate tap water to the populace. Such will increase the quality of life and improve the economy of the area.\r\n