Hydrogeochemical and salinity appraisal of surficial lens of freshwater aquifer along Lagos coastal belt, South West, Nigeria

Abstract

In order to determine the hydrogeochemical processes and salinity status of the surficial lens of freshwater aquifer in the Lagos coastal basin, physicochemical parameters and hydrogeochemical tools were employed in this study. These tools include existing methods such as Piper diagram, Durov diagram, Gibb's diagram, statistical analysis and geochemical modelling, and the newly proposed cationic contribution evaluation and ionic ratio bivariate plots. The Piper plot revealed that chemical facies is rich in (Ca, Mg, Cl and HCO 3 ) and (Ca and HCO 3 ) for the groundwater in both wet and dry seasons while Mg-Cl and Na-Cl water types characterised the lagoon and the Ocean, respectively. The surficial aquifer is an essentially freshwater in the dry season and partly saline in the wet season due to flash flood, marine aerosol precipitation and infiltration from the surrounding brackish surface waters. The Ca 2þ þMg 2þ vs total cation (TZ þ ); HCO 3 -/Ca 2þ vs Ca 2þ /Mg 2þ and HCO 3 -/Ca 2þ vs Ca 2þ /Na þ plots as well as geochemical modelling indicated that carbonate weathering is the dominant chemical process controlling the groundwater chemistry for both seasons. In a descending order, water-rock interaction, ion exchange and evaporation are the geochemical processes controlling the groundwater quality in the area. Besides the natural processes, factor analysis revealed the imminent influence of anthropogenic activities (industrial and domestic) on the groundwater chemistry indicated by the presence of Mn, Fe, Ni, Cd, Pb, Cu and NO 3 above the permissible limit of drinking water standard, particularly in the wet season. In addition to the successful application of the proposed ionic plots, the study justifies the importance of multiple tools application in the hydrogeochemical deductions and recommends consistent monitoring of the shallow aquifers in the Lagos coastal basin.

Study of the quality index of groundwater (GWQI) and its use for irrigation purposes using the techniques of the geographic information system (GIS) of the plain Nekor-Ghiss (Morocco)

“…Numerous geological processes, including ion exchange, reverse ion exchange, evaporation, silicate weathering, water-rock interactions, sulfate reduction, oxidation processes, and human Frontiers in Environmental Science frontiersin.org activity, have an impact on electrical conductivity (Yusuf et al, 2021;Hao et al, 2022). The findings (Table 1) demonstrate that the samples examined compared to the WHO (2022) standard (1,500 μs/cm).…”

Investigation of groundwater vulnerability to open dumpsites and its potential risk using electrical resistivity and water analysis

“…The unfavourable dumpsite phenomena have been a difficult task for Nigeria to manage due to the ever-upsurging solid waste generated [ 8 ]. These situations predict difficult times for the future of environmental management in Nigeria [ [9] , [10] , [11] , [12] ], and the rest of the African nations [ [13] , [14] , [15] ]. Therefore, the prevailing indiscriminately disposal of solid wastes in open dumpsites in developing nations has reached a critical situation that poses hazardous impacts on human habitations [ 2 , 16 , 17 ].…”

An integrated seawater intrusion assessment in the Moroccan Ghiss-Nekor coastal aquifer using hydrogeochemical and geospatial techniques

“…Typically, SWI is assessed through a combination of hydrochemical and either 1) isotopic methods as seen in studies by Liu et al (2017), Chafouq et al (2017), Bahir et al (2018), Zhang et al (2015), Nair et al (2015), Liu et al (2014), Zhang et al (2022), Xia et al (2022), Chidambaram et al (2022), Balasubramanian et al (2022), Mosaffa et al (2021), Kim et al (2021), Telahigue et al (2020), Dhakate et al (2020), Boumaiza et al (2020), Nogueira et al (2019), Maurya et al (2019), and Mongelli et al (2013), or 2) geophysical methods as seen in studies by Sae-Ju et al (2020), Gopinath et al (2019), Sae-Ju et al (2018), Fadili et al (2015), Kura et al (2014), Lagudu et al (2013), Gurunadha Rao et al (2011), Kouzana et al (2009), 3 Lee et al (2002), and Bouzouf et al (2001). These combinations of interdisciplinary methods have been successful (Werner et al 2013;Kura et al 2014;Jiao and Post 2019;Yusuf et al 2021), but isotopic and geophysical methods can be expensive, which leads to their limited use in developing countries (Clark and Page 2011;Asare et al 2021). Alternatively, the hydrochemical approach can be used on its own to characterize SWI and has been effective through the use of geochemical modeling, ionic ratios, and SWI indices (Telahigue et al 2020;Subba Rao 2021;Ayar...…”