Litho-stratigraphic and hydrogeological evaluation of groundwater system in parts of Benin Metropolis, Benin City Nigeria: The key to groundwater sustainability

Abstract

Previous studies revealed that soil properties play a significant role in aquifer contamination. Consequently, it is necessary to understand the nature and properties of soil in carrying out groundwater evaluation. This study evaluates the subsurface geology and groundwater flow direction in Okpagha, Iguomo, Ikhueniro and Okhuahe suburbs in Benin City, Nigeria. Six boreholes were drilled by means of manual (rotary) method in different parts of the study area and each borehole was logged in order to understand the lithology, depth to water table, static water level as well as flow direction. The results obtained show that aquifer within the study areas were confined, semi confined to unconfined and was dominated by sands with minor clay and lignite interbed. It was observed that aquifer becomes shallower towards eastern portion of the study areas with increase in sand and decrease in clay materials. It was also observed that groundwater flow map revealed a flow direction of NorthWest to SouthEast from North West to South East. The decrease in the depth of aquifer and increase in sand material could be explained by the closeness to sea level. This phenomenon can enhance the infiltration of contaminants into aquifer thereby contaminating the groundwater bodies. It is therefore necessary to constantly monitor the groundwater quality in this suburbs in order to be aware of the quality of water resources being consumed because poor water quality can impact public health negatively. Furthermore, the authors advise that boreholes should be drilled in the direction of groundwater flow for maximum yield

Burial leakage: A human accustomed groundwater contaminant sources and health hazards study near cemeteries in Benin City, Nigeria

“…In the case of this study, common originality could be considered priority in reference to Tredoux et al [ 55 ] records. In general, high levels of correlations observed among parameters characterised in the groundwater support the findings on litho-stratigraphic and hydrogeological study by Omorogieva and Imasuen [ 59 ] which revealed that the materials overlaying the aquifer within Benin City are dominated by sands with traces of clay and lignite inter-bed and this condition has enhances infiltration of contaminants into aquifer.…”

“…Our results showed incidents of organic pollution and heavy metal contamination of the groundwater [ 50 , 95 ] which are potential impacts from burials leakage [ 23 , 24 ]. This finding of our research study further portrays the low capacity of the overlaying earth materials (dominated by sands) to prevent infiltration of contaminants [ 59 ]. Trang and Luan [ 6 ] reported incident of heavy metal contamination in groundwater sampled from area of two longstanding cemeteries in Ho Chi Minh City.…”

“…The brown reddish-yellowish colour is because of the limonitic coatings. Benin Region is drained by three river networks which include Ikpoba River, Ogba River and Owigie-Ogbovben River [ 62 ] while the hydrogeology study by Omorogieva and Imasuen [ 59 ] showed the aquifer underlying Benin region to be shallow flowing in direction of North-West to South-East from Northwest to Southeast and the overlaying materials dominated by sands with traces of clay and lignite inter-bed. Topography of this area is undulating in nature and has been described as a tilled plain in the southwestern direction as it is surrounded by the Benin historical moats [ 62 , 64 ].…”

“…It is worthy to note that no previous studies have investigated the health risks associated with presence of carcinogenic and non-carcinogenic metals in groundwater resources upon which the populace within the locality of this study depend on to meet their daily demand for water. Our study is significant as it determines the extent to which the groundwater is impacted as previous study on litho-stratigraphic and hydrogeological [ 59 ] revealed that the materials overlaying the aquifer within Benin City are dominated by sands with traces of clay and lignite inter-bed and this condition has relatively low barrier to prevent infiltration of contaminants into aquifer. The results of our study would provide an important scientific understanding of the impact of longstanding cemeteries on groundwater quality and invariably argument valuable information for various stakeholders including policymakers and town/urban planning managers to implement appropriate remediation methods that would ensure the safety of groundwater resources.…”

Assessments of Heavy Metal Contamination in Groundwater Source from Benin Formation Aquifer in and around Dumpsite Environment, and its Impact on Human Health

“…Some aquifers within Benin Metropolitan City (BMC) Nigeria are susceptible to groundwater contamination due to open dumping of municipal and hospital wastes in excavated sites. For example, Omorogieva (2018) reported that wastes dumped in Ikhueniro open dumpsite in Benin City include lead acid battery, sewage and industrial effluents, ferrous and non-ferrous materials, abandoned vehicles, polythene wastes, chemical containers, food wastes, e-waste, garden wastes, paint and chemical solvent. These wastes contain hazardous environmental contaminants like Pb, Fe, Cr, Mercury (Hg), Arsenic (As) among others, and are beyond the OMOROGIEVA, OM; TONJOH, JA; BRISIBE, O average crustal values.…”