Geophysical investigation using electrical resistivity method was conducted for groundwater exploration at Kashere town, with the objective of delineating channel-fill sand that may exist within the underlying Gombe Sandstone Formation in the study area. The survey utilizes the Vertical Electrical Sounding (VES) technique and the Schlumberger electrode array to acquire data at regular station intervals of 100 m along three E-W trending profiles (P1, P2, and P3) of 600 - 700 m in length. The investigation was able to delineate three channel-fills in the study area. One of the channel-fills is exposed along profile P2 and filled with clayey-sand and lateritic materials to the depth of about 10 m. The other two channel-fills occur as multi-storey channels with upper and lower channel that are centred at 200 m along profile P3. The upper channel occurs at the depth between 2 and 8 m and has a maximum thickness and lateral extent of about 7 and 200 m, respectively. This channel is filled with silty clay to very fine-grained sand that may not be of good reservoir quality. The second, lower channel is confined within fine-grained sediment and filled with medium- to coarse-grained sands that can serve as potential reservoir for groundwater storage and extraction. This channel-fill occurs at the depth between 8 and 22 m beneath profile P3 an

Geophysical method was used to study the subsurface properties formation of hydrocarbon contamination on a recent spilled and clean-up site. Electric technique was adopted, using Schlumberger with maximum current electrode spread of 200 m and Wenner array spread of 120 m laterally to determine the resistivity of the subsurface. A total of four data was collected; one Schlumberger to infer the lithology, while three Wenner to obtain the profile lateral changes. The IPI2WIN and RES2DINV software were used to interpret the field data. The result obtained showed that, the 1D data have resistivity values of 0.00045Ωm, 0.0032 Ωm and 0.829 Ωm at thicknesses 0.5m, 0.5m and 15.1m respectively, which implies that all three layers are top soil. For the 2D case, profile1 indicate that plume is spread downward from about 75m mark and laterally between 65 m and 85 m mark, while profile 2 serves as control, indicate absent of plume due to the direction of flow because of the elevation point. Geochemical analysis result was carried out in the laboratory, using the UV spectrometer, indicates high Total Hydrocarbon Content (THC) concentration of soil at 87.5 for mg/kg for S1, 205mg/kg for S2 and 85mg/kg for S3 when compared with the WHO permissible standard of 30mg/kg for soil, which confirm the hydrocarbon plume from the geophysical model. The result obtained will help to give a guide line direction, the best remediation technique to carry out clean-up on the surface/subsurface soil contamination with crude oil spill.

This study presents a comprehensive hydrochemical analysis of groundwater in a specific area, focusing on major ions such as calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), bicarbonate (HCO3 -), sulfate (SO4 2-), chloride (Cl-), nitrate (NO3 -), fluoride (F-), phosphate (PO4 -), and ammonium (NH4 +). The concentrations of these ions were measured and analysed against Nigerian and World Health Organization (WHO) standards for drinking water quality. The findings reveal that the groundwater in the study area is generally within acceptable limits for drinking water quality, with concentrations of major ions falling within regulatory standards. The sources of these ions vary, with calcium and magnesium originating from calcium-rich rocks and metasediments, while sodium is derived from clays and minerals like feldspars. Potassium may stem from K-bearing minerals or agricultural practices. Bicarbonate exhibits the highest concentration among the analysed ions, indicating its prevalence in the groundwater. Sulfate concentrations are below recommended limits, possibly originating from the dissolution of minerals in amphibolites. Chloride levels, though within permissible limits, show localized increases around areas with anthropogenic activities like waste disposal. Nitrate concentrations indicate potential pollution sources, including decaying organic matter and agricultural practices. Fluoride levels are generally below maximum limits, with possible sources being fertilizer and agrochemical leaching. Phosphate concentrations, primarily from agricultural activities, remain within acceptable ranges, except for a few samples. Physical parameters such as pH, total dissolved solids (TDS), and electrical conductivity (EC) provide further insights into groundwater quality. The dominance of calcium and bicarbonate ions reflects geological influences, while elevated nitrate and chloride levels suggest anthropogenic contributions. Hydrogeochemical analyses, including Piper trilinear plots, Durov plots, and Stiff diagrams, elucidate groundwater facies and geochemical processes. Seasonal variations in water types and geochemical evolution are observed, with different water facies identified during wet and dry seasons. The study underscores the importance of comprehensive hydrochemical analyses in understanding groundwater quality, identifying potential pollution sources, and informing sustainable water resource management strategies in the study area. Further research could explore long-term trends and dynamic interactions between hydrogeochemical processes and anthropogenic activities. Keywords: Anthropogenic sources; Environmental c

Water of good quality for domestic, industrial, and agricultural purposes is very essential to public health and overall wellbeing of the people. Domestic and agricultural activities are carried out within the study area without considering the geochemical and biological processes that occur in the groundwater zone. The water quality of Jalingo Area NE Nigeria was investigated with the aim of determining its suitability for domestic, industrial, and agricultural purposes. A total of 50 water samples were collected from surface water and groundwater sources which were analysed using standard methods: Atomic Absorption spectrophotometry for cations and conventional titration for anions. The water was characterized employing chemical indicators such as pH, sulphate, chloride and nitrate and the results indicate that most groundwater samples and some surface water samples are largely suitable for human consumption. Most of the surface water samples revealed total coliform bacteria values above the international permissible limits whereas most of the groundwater samples indicate values that are less than the international permissible limits. The chemistry of the different water sources suggests that alkaline earths (Ca+Mg) significantly exceed the alkalis (Na+K) and weak acids (HCO3+CO3) exceed the strong acids (CI+SO4) suggesting the dominance of CO3 weathering followed by silicate weathering. Hydrogeochemical studies disclosed the Ca2+- SO4 2- , Ca2+-CI-, Na+-HCO3 - and Na+-Cl- as the dominant ion types for surface water samples and Na+-HCO3 2- and Ca2+-HCO3 as the major ions for groundwater samples. The homogenous composition of groundwater indicates a common origin and source whereas the nonhomogenous composition of surface water samples reveals active groundwater mixing and significant water-rock interaction, the irrigation indices determined revealed 642 values of TDS (<421 mg/l), SAR (<10), EC (<750 μS/cm) and TH (<250 mg/l) obtained for most of the water sources are found to be within the safe permissible limits for irrigation. However, some samples which displayed values of MAR (> 50%), PI (<25%), KR (>1.00) and SSP (>75%) suggest salinity hazards and should be treated before use. The groundwater samples are generally slightly acidic, largely soft, with fairly low to moderate concentrations of dissolved solids that fall within the international limits for drinking domestic and irrigation. The concentration of nitrate in about 71% of the water samples is higher than the recommended limits of 0.3 mg/l and 10 mg/l respectively should be treated before use.