Abstract This study highlights the distribution of
hydraulic conductivity (K) in the regional aquiferous Ajali
Formation of SE-Nigeria on one hand and assesses the
possible influences of textural and geochemical characteristics
on the hydraulic conductivity on the other hand. The
investigation approach involved field sampling and collection
of 12 sandstone samples from different outcrop
locations, followed by laboratory studies such as grain-size
analysis (GSA), constant head permeameter test and geochemical
analysis of major and trace elements using X-ray
fluorescence method. GSA and textural studies show that
the sandstones range from fine to medium sands, constituting
about =–99% sand fraction, with graphic mean
grain size of 0.23–0.53 mm. Other parameters such as
coefficient of uniformity (Cu) range from 1.58 to 5.25 (av.
2.75), while standard deviation (sorting) values of 0.56Ø–
1.24Ø imply moderately well sorted materials. In addition,
the order of the estimated K values is Kpermeameter[
KBeyer[KHazen[KKozeny-Carmen[KFair-Hatch with average
values of 1.4 9 10-3, 4.4 9 10-4, 3.8 9 10-4, 2.2 9 10-4
and 8.1 9 10-5 m/s, respectively. These values fall within
the range of 10-5 and 10-3 m/s for fine to medium sands.
However, multivariate factor analysis of the data revealed
significant positive dependence of the empirically determined
K values on graphic mean grain size and percentage
sand content and much less dependence on sorting and total
porosity. Geochemical profiles of the fresh samples are
dominated by quartz with corresponding SiO2 content of
76.1–98.2% (av. 89.7%) while other major oxides are
generally below 1.0 wt.% in the fresh samples. However,
the ferruginized samples exhibited elevated concentrations
of Al2O3 (3.50–11.60 wt.%) and Fe2O3 (1.80–3.60 wt.%),
which are clear indications of weathering/ferruginization
processes with attendant trace metal release/enrichment
(2.5 mg/l Cu, 7.5 mg/l Pb, 6.5 mg/l Zn, 3.9 mg/l Ni and
19.6 mg/l Cr) call for concern in respect of the chemical
quality of the groundwater system. The associated
groundwater is generally soft, slightly acidic, and with low
dissolved solids (EC = 14–134 ls/cm) dominated by silica;
implying water from clean sandy aquifer devoid of
labile and weatherable minerals. Nonetheless, most of the
metals (with exception of Si, Fe and Mn) exhibited higher
degree of mobility (2–12 folds), which can be attributed to
reduction of Fe-/Mn-oxyhydroxides as sinks/hosts for trace
metals. Consequently, infiltration-induced geochemical
reactions (redox, ferruginization and leaching processes)
signify potential environmental impact in terms of
groundwater quality as well as borehole/aquifer management,
especially under humid tropical environment of the
study area.
Tijani, M (2021). Hydraulic, textural and geochemical characteristics of the Ajali Formation, Anambra Basin, Nigeria: implication for groundwater quality. Afribary. Retrieved from https://tracking.afribary.com/works/hydraulic-textural-and-geochemical-characteristics-of-the-ajali-formation-anambra-basin-nigeria-implication-for-groundwater-quality
Tijani, Moshood "Hydraulic, textural and geochemical characteristics of the Ajali Formation, Anambra Basin, Nigeria: implication for groundwater quality" Afribary. Afribary, 22 Apr. 2021, https://tracking.afribary.com/works/hydraulic-textural-and-geochemical-characteristics-of-the-ajali-formation-anambra-basin-nigeria-implication-for-groundwater-quality. Accessed 09 Nov. 2024.
Tijani, Moshood . "Hydraulic, textural and geochemical characteristics of the Ajali Formation, Anambra Basin, Nigeria: implication for groundwater quality". Afribary, Afribary, 22 Apr. 2021. Web. 09 Nov. 2024. < https://tracking.afribary.com/works/hydraulic-textural-and-geochemical-characteristics-of-the-ajali-formation-anambra-basin-nigeria-implication-for-groundwater-quality >.
Tijani, Moshood . "Hydraulic, textural and geochemical characteristics of the Ajali Formation, Anambra Basin, Nigeria: implication for groundwater quality" Afribary (2021). Accessed November 09, 2024. https://tracking.afribary.com/works/hydraulic-textural-and-geochemical-characteristics-of-the-ajali-formation-anambra-basin-nigeria-implication-for-groundwater-quality