Hydrogeochemical investigation and characterization of shallow groundwater within Ankpa Town, North Central Nigeria

Abstract

Physico-chemical analysis of groundwater samples from Ankpa, north central Nigeria was carried outto investigate the quality of the water for drinking and irrigation purposes. The results revealed water of average low pH, indicating slightly acidic conditions of the water. The water is soft, and it is characterized as Na + +K -HCO 3 type. It is good for drinking and other domestic uses. Four indices were evaluated from the groundwater chemistry in order to establish the suitability of the water for irrigation purposes. They are the sodium adsorption ratio (SAR), the percentage sodium (%Na), the magnesium hardness (MH) and the permeability index (PI). The SAR values range from 0.86 to 11.19, with an average of 5.68. The interpretation indicates that the groundwater is good to excellent for irrigation. It further shows that over 90% of the samples can be classified as S1 waters, with no alkali hazard anticipated for the crops grown with the water. The range of the %Na in the groundwater in this study is between 16.28 and 73.97, with an average value of 51.27. This shows that the water ranges from excellent to doubtful for irrigation. The magnesium hardness (MH) in the groundwater ranges from 2.05 to 41.04%, with an average of 20.35%. This indicates that the entire water is safe for use for irrigation purposes. The chloride and sulphate concentrations in the groundwater indicate that the water is excellent for irrigation. However, the permeability index shows completely opposite conditions in the area, with all samples with values above 75.

Evaluation and characterization of groundwater of the Maastrichtian Lafia formation, Central Benue trough, Nigeria

“…The trend of the Ca 2+ + Mg 2+ water type in a straight line on the Piper diagram (figure 6) is an indication of a solution or precipitation. The source of the HCO − 3 + CO − 3 water type is rainfall mixed with atmospheric carbon dioxide, usually low in calcium and magnesium and is said to be juvenile water (Akpah et al 2017). The Stiff pattern diagrams showed similar patterns for all samples with the exception of samples 8, 15 and 17.…”

“…It showed that 23.33% of water samples are good, permissible and doubtful, respectively, while 16.67% are excellent and 13.34% are unsuitable for irrigation. Low Na + water can be used for irrigation on all soils with minimal danger of harmful exchangeable Na + developing (Singh et al 2009), while on the other hand, high sodium water in most soils will require special soil management, such as good drainage, high leaching and organic matter as it produces harmful exchangeable sodium (Akpah et al 2017). High Na% in water will result in the replacement of Mg 2+ and Ca 2+ by Na + which impedes soil permeability, reduces soil drainage, affects soil structure and aeration and therefore, affects plant growth (Singh et al 2008(Singh et al , 2009Akpah et al 2017).…”

“…Based on SAR, 96.67% and 3.33% of the groundwater are classified as excellent and doubtful waters, respectively. The low SAR of the water samples implies that the water will make the soil soft, loose and pervious with little sodium accumulation in the soil, as high SAR is responsible for compact, hard and impervious soils (George 1983;Akpah et al 2017). Plants in the study area will have low susceptibility to sodium hazard or sodicity (Uzoije et al 2015) as the soil's physical conditions will be suitable for good plant germination.…”

“…groundwater ranges from 6.52% to 60.58%, with an average value of 25.83%. MH >50 is considered unsuitable or harmful for irrigation (Szabolcs and Darab 1964;Singh et al 2009;Brindha et al 2014;Akpah et al 2017). Only 6.6% of the water samples fall within this category, while 93.4% with MH <50 are considered suitable for irrigation (Al-Tabbal and Al-Zboon 2012).…”

“…Kumar (2013) studied groundwater chemistry and identified natural processes as controlling factors of the hydrochemistry, while Ishaku et al (2012) identified anthropogenic contaminations, natural mineralisation and cation exchange as factors controlling the hydrochemistry. Groundwater quality for drinking and agricultural or other purposes has been studied (Onwuka et al 2004(Onwuka et al , 2013Ehirim et al 2009;Prasanna et al 2011;Ishaku et al 2012;Rao et al 2013;Omonona et al 2014;Das and Nag 2015;Akpah et al 2017).…”