Hydrogeochemical Characterization and Vulnerability Assessment of Shallow Groundwater in Basement Complex Area, Southwest Nigeria

Abstract

Thirty-five (35) groundwater samples from Owo area were analyzed for physicochemical parameters. Results show that the mean value of pH is 6.32, TDS is 208.92 mg/l, temperature is 28.77°C, EC is 545.16 μs/cm; TH is 111.09 mg/l, SO4 is 71.73 mg/l, Cl is 0.07 mg/l, HCO3 is 14.09 mg/l, Na is 25.06 mg/l, Ca is 37.07 mg/l, K is 24.36 mg/l and Mg is 4.41 mg/l. The results were compared to the WHO and NDSQW standards. All parameters were within the permissible limit except EC in well OW6 and K is above the stipulated standards in 69% of the total samples. The high concentration of K is linked to the use of NPK fertilizer in the area for agricultural purposes. The groundwater belongs to Ca-Na-K-SO4 and Na-Ca-SO4 water type respectively. The ionic concentration in the groundwater is due to the dissolution of the rock that makes up the aquifer. Plagioclase and silicate-bearing rocks are the sources of major ions in the water. SAR, PI, RSBC and KR reveals that groundwater in the area is good for irrigation purpose. DRASTIC model further revealed that groundwater in the area is less vulnerable to contamination under the current environmental conditions.

Control of aquifer weathering degree to the groundwater chemical composition in Wates Coastal Aquifer, Yogyakarta, Indonesia

“…Groundwater chemical composition depends on several processes: (i) mixing of saline water from various origins (marine intrusion, former trapped sea water,etc.) with fresh water of aquifer, (ii) rock-water interactions through chemical dissolution/precipitation of aquifer materials, (iii) evaporation and (iv) cation exchange processes on clay [2]. Concomitantly, geochemical processes involve the interaction of lithology with water leading to the development of secondary minerals [3].…”

Groundwater quality assessment and characterization of shallow basement aquifers in parts of ado ekiti metropolis, Southwestern Nigeria

“…Water of this facies is usually pure, natural and safe groundwater [31]. This type of water typified any water tapped from continental basement (weathered and fractured) aquifers [12]. Mixed CaNaHCO 3 type occupies the smallest water type (11%) of the study area which is usually formed from the recharge water (precipitation) and dissolution of minerals along the flow path [32,74].…”

“…Several methods have then been adopted in the evaluation of groundwater pollution. Hydrochemistry has become one of the tools in the evaluation of water suitability for different purposes such as industrial, domestic and agricultural purposes [7][8][9][10][11][12][13][14]16]. This is due to the ability of water in dissolving anything (minerals, rocks and solids), and it comes in contact with.…”

“…Other methods such as multivariate statistical analysis (factor analysis (FA), hierarchical cluster analysis (HCA), analysis of variance (ANOVA) and ordinary kriging (OK)) have also aided further understanding and interpretation of the hydrogeochemical and bacteriological processes influencing groundwater quality. This is due to their simplicity and straightforwardness interpretation in the characterization of groundwater quality [12,13,23,24]. The contribution of geogenic and anthropogenic inputs in the pollution of groundwater has been recorded in several places [25][26][27][28].…”

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

“…Groundwater pollution assessment studies have aided accurate assessment of the vulnerability of groundwater to pollution coupled with in-depth understanding and knowledge of hydrogeochemical processes which have been found important in groundwater quality assessment. Hydrogeochemical processes greatly influence the pollution or contamination of groundwater all over the world (Krishna Kumar et al 2014;Batabyal and Chakraborty 2015;Adewumi et al 2018;Batabyal 2017;Lapworth et al 2017;Olofinlade et al 2018;Oyedele et al 2019). This study is, however, aimed at the delineation of groundwater recharge and discharge areas in an urban metropolis, like Akure, the capital city of Ondo State, south-western Nigeria, for their pollution potential as well as the hydrogeochemical processes prevailing in the area.…”