Journal of Geography, Environment and Earth Science International 19(1): 1-24, 2019; Article no.JGEESI.32939 ISSN: 2454-7352 Geochemical Characterization and Assessment of Groundwater Quality in Owerri Metropolis, South- Eastern Nigeria C. Chukwuemeka Onyeanuna1*, Patience John2 and N. Temple Nwankwo3 1Department of Environment, Land and Infrastructure, Polytechnic University of Turin, Piedmont, Italy. 2Department of Geosciences, Federal University of Technology Owerri, Imo State, Nigeria. 3Department of Agricultural Technology, Federal Polytechnic Oko, Anambra State, Nigeria. Authors’ contributions This work was carried out in collaboration between all authors. Author CCO designed the study, performed the statistical analysis and wrote the protocol. Author PJ performed the sampling, laboratory measurement and wrote the first draft of the manuscript. Author NTN reviewed the analyses of the study and literature searches. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JGEESI/2019/32939 Editor(s): (1) Dr. Kaveh Ostad-Ali-Askari, Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Iran. (2) Dr. Wen-Cheng Liu, Department of Civil and Disaster Prevention Engineering, National United University, Taiwan and Taiwan Typhoon and Flood Research Institute, National United University, Taipei, Taiwan. Reviewers: (1) Gopal Krishan, National Institute of Hydrology, India. (2) S. Selvakumar, Centre for Geotechnology, Manonmaniam Sundaranar University, India. (3) Ahoussi Kouassi Ernest, Universite Felix Houphouet Boigny, Cote D’ivoire. (4) Dorota Porowska, University of Warsaw, Poland. Complete Peer review History: http://www.sdiarticle3.com/review-history/32939 Received 04 November 2018 Original Research Article Accepted 23 January 2019 Published 07 February 2019 ABSTRACT A total of five borehole samples were collected from five towns in Owerri metropolis, South-eastern Nigeria and subjected to physio-chemical analysis using atomic absorption spectrophotometer (AAS) and other standard equipment with the aim of characterizing and analysing the groundwater quality indicators. These quality indicators are namely: pH, temperature, total hardness, turbidity, electrical conductivity, total dissolved solids, total suspended solids, dissolved oxygen, Ca2+, Mg2+, + + - 2- - - 2+ 2+ 2+ 2+ 2+ 2+ Na , K , HCO3 , SO4 , Cl , NO3 , Fe , Zn , Pb , Cu , Mn , and Cr . With the aid of geochemical diagrams acquired using Aquachem 2014.2, we classified the groundwater samples into their respective hydrogeochemical facies, identified their relative similarity and demonstrated the irrigability of the groundwater. The results showed that the groundwater quality indicators occur in _____________________________________________________________________________________________________ *Corresponding author: E-mail: [email protected]; Onyeanuna et al.; JGEESI, 19(1): 1-24, 2019; Article no.JGEESI.32939 the groundwater in amounts that fall within their respective permissible limits as set by World Health Organization (WHO) Drinking Water Standard, and therefore ascertained the groundwater portable and suitable for drinking. The pH of the groundwater has a mean value of 6.7 with a standard deviation of 0.26. The relative abundance of the majority of cations follows this sequence - Na+ > 2+ + 2+ - - 2- - Ca > K > Mg , while that of the anions follow this sequence - HCO3 > Cl > SO4 > NO3 . Heavy metals constituents of the groundwater follow this order of relative abundance - Zn2+ > Fe2+ > Mn2+ > Cu2+ > Cr2+ > Pb2+. Three hydrogeochemical facies were identified in the area and they are: the + - 2+ + - 2+ 2+ - Na —Cl water type, the Mixed Ca -Na -HCO3 water type and the Ca -Mg -HCO3 water type. Great similarities were identified between the geochemical composition of the samples and they are all evidently suitable for irrigation purposes. The TDS level and concentration of Ca2+, Mg2+ and Cl- demonstrated the freshness and softness of the groundwater, with no laxative effects. From series of computations and plots, silicate weathering and seawater intrusion were deduced to be the dominant factors controlling the groundwater chemistry, though there is evidence of poor rock dissolution – immature water-rock equilibrium. Keywords: Groundwater; aquifer; water quality; concentration; geology; geochemical; fresh water. 1. INTRODUCTION soil quality indices but equally affected the productivity of agroecosystems [3]. Land use Water is essential for livelihood and socio- change has significant impact on the feedback of economic development of any community. Fresh hydro-climatic processes on the surface water resources are unevenly distributed hydrology [4]. Kigne [5] stated that urbanization throughout the world and their availability are is the most forceful of all the changes that affect becoming scarce day by day owing to population the hydrology of an area; this forcefully results to growth and diverse human activities. In quest to a decrease in the infiltration rate of water into the fill up the gap created by the absence of fresh soil as the excess flow becomes runoff. Changes surface water resources, groundwater is in groundwater quality with subsequent exploited to meet the demand exerted by various contamination can undoubtedly, affect human sectors. Groundwater may become surface water health [6]. Groundwater quality depends, to some through springs and drainage into rivers, lakes degree, on its chemical composition which may and wetlands. Conversely, surface water bodies be modified adversely by natural and may seep into the ground and recharge the anthropogenic sources [7]. Rapid urbanization, aquifers, e.g. when flood water percolates especially in developing countries like Nigeria, through the vadose zone to the saturated zone has affected the availability and quality of [1]. Movement of faults and other forms of groundwater due to improper and uncontrolled tectonism on the earth is predictably influenced waste disposal practice, especially in urban by the interplay of groundwater lubrication. areas. Groundwater may not be confined only to earth; the formation of some of the landforms observed Groundwater pollution is a growing on Mars may have been influenced by environmental problem, especially in developing groundwater, there is also evidence that liquid countries and impairs the usefulness of water, water may also exist in the subsurface of causing hazard to public health through toxicity Jupiter's moon Europa [2]. or spread of disease [8]. Wastes generated in the study area are disposed of in open dumps, along In Nigeria, many major cities, suburbs and river banks, erosion sites, septic tanks, pit villages depend on groundwater for water latrines, abandoned borrow and quarry-pits. Oil supplies, mainly because of its abundance, and gas spills from the numerous petrol stations, stable quality and because it is inexpensive to industrial effluents, and wastes from agricultural exploit. Owerri and its environs have witnessed a activities are also potential sources of pollution in substantial industrial and population growth the area. Particularly, open dumps are sited during the past two decades. Demography and indiscriminately in Owerri without consideration fast urbanization of Owerri metropolis have led to of the protection of the underlying aquifer [9]. profound social, economic and ecological This results in aquifer deterioration, since some alterations to the extent that poses an increasing of these waste products may be discharged threat to the attainment of a healthy environment. directly into the aquifer system [10]. Through Land use trend in Owerri not only affected the precipitation, irrigation waters or liquid wastes, 2 Onyeanuna et al.; JGEESI, 19(1): 1-24, 2019; Article no.JGEESI.32939 water soluble wastes can be dissolved and the set standards. Some of these constituents eventually seep through the vadose zone of the occur in significant amounts while others are of soil into the saturated zone to pollute the minor importance or are present as trace groundwater. Once groundwater is elements. Spatial variation in groundwater quality contaminated, its quality cannot be restored by in response to local geologic set-up and stopping the pollutants from source [11,12]. As anthropogenic factors warrants the evaluation of groundwater has a huge potential to ensure the quality for many purposes including that of sustainable water supply, it is important that human consumption [7]. Since groundwater human activities on the surface do not negatively occur in geologic setting which is dynamic, it affect the precious resource [13]. Poor possible for near-surface aquifer that produced environmental management creates havoc on clean water in a given year to produce polluted the water supply and hygiene and undermines water in the following year. Therefore, constant public health [14]. monitoring of groundwater quality is vital to ascertain their fitness for human consumption In sub-Saharan Africa, the water use efficiency and to determine the appropriate remediation estimated for the year 2005/07 and projected for measure to be taken if significant alterations to the year 2050 is 22 and 25 percent respectively, the quality are observed. which is by far less than the world average which is 44 and 46 percent respectively [15]. Although, Some scholars who have studied some aspects the current water withdrawal for agriculture and of the hydrogeology in South-eastern Nigeria other purposes is