Physicochemical and Microbiological Parameters in Ground and Surface Water Quality Assessment

Physicochemical and Microbiological Parameters in Ground and Surface Water Quality Assessment Salako Adebayo Olayinka1, Olaiya Tolulope Bolanle2 1.Department of Mining and Geological Sciences, Ministry of Solid Minerals Development, Ilorin, Kwara State, Nigeria. 2University of Science and Technology of China, Hefei, China. Abstract Water is a vital and irreplaceable natural resource that plays a fundamental role in supporting the long-term viability of both terrestrial and aquatic life within the ecosystem. Water can be found in two forms: surface water and groundwater. The presence of water above or below the ground level determines which form it takes. Regardless of its geographical location, both ground and surface water are subject to the impacts of land use and various human activities such as mining, agriculture, and industrial development. The availability of potable water for human consumption is contingent upon the evaluation of water resources. Therefore, the objective of this study is to evaluate the quality of water based on its various forms of occurrence by utilising specific parameters, which include the Microbiological and Physiological indices. Keywords: Water Quality, Microbiological, Physicochemical, Freshwater, Groundwater, Surface-water The presence and maintenance of life in various habitats, whether on land or in water, rely on the presence, availability, and utilisation of fundamental natural resources, with water being of utmost importance. Studies have indicated that approximately two-thirds of the Earth's surface is covered by water, with the oceans comprising 97% of this total. In contrast, only 2.5% of the world's water exists in the form of fresh water (Itedo & Itodu, 2019; Oni et al., 2020). According to Jayalakshmi and Lakshmi (2014), approximately 75% of these resources are found in glaciers and ice caps, with lakes, rivers, and groundwater accounting for the remaining 25%. Water, as a crucial natural resource, plays a pivotal role in supporting various living systems. Additionally, it has demonstrated its significance in facilitating the operations of mining, industrial, and agricultural sectors, particularly in the domains of production and sewage disposal. The rapid growth of the human population, facilitated by advancements in medical, agricultural, and industrial technologies, has placed significant stress on the availability of water resources. This has resulted in escalating demands for water and a consistent decline in its availability, ultimately leading to a shortage of clean and potable water. The issue of global concern led to the declaration made in July 2016 during the United Nations Human Rights General Assembly, which emphasised the importance of ensuring access to clean and safe water that is suitable for human consumption (UN, 2016). The primary sources of water for domestic and industrial use are typically groundwater and surface water. These sources are susceptible to the indiscriminate disposal of effluents, gangue materials from mining activities, industrial by-products, and other contaminants.The likelihood of water bodies in close proximity to industries or areas with high population density being susceptible to pollution from agro-chemical discharge or indiscriminate sewage disposal increases as a result of the growing demand for industrialised goods. The main causes of surface water pollution and degradation of water quality are anthropogenic sources, including untreated industrial effluents, improperly disposed domestic wastes, and agricultural runoff (UN, 2016; Uddin and Jeong, 2021; Hasan et al., 2019). The presence of these waste materials, in conjunction with shifts in climatic conditions, progressively fosters the proliferation of disease-causing microorganisms. This, in turn, exacerbates human-induced activities that disrupt the natural hydrological cycle, ultimately resulting in a decline in the quality of water resources.According to Jin et al. (2020a, 2020b), water resources face significant endangerment due to pollution resulting from human activities and improper agricultural drainage practises in river systems. As the deposition of pollutants from chemical sources increases in aquatic environments, there is a corresponding increase in the proliferation of faecal microorganisms and pathogens, which subsequently impacts the quality of water. According to Caraco et al. (2003), the importance of water quality in rivers extends beyond human needs and encompasses the well-being of animals and the preservation of environmental integrity.According to Anoksike and Akaniuk (2007), the contamination of freshwater ecosystems, including rivers, streams, lakes, and ponds, primarily arises from industrial effluents, municipal waste disposal, and surface runoff. Surface water, such as lakes, rivers, streams, and springs, has been recognised not only as a source of water for essential domestic and irrigation purposes, but also as a natural habitat for aquatic organisms that provide a valuable protein source and other crucial resources for humans and various other organisms.Water sources provide significant social and economic advantages, such as tourism and recreation, which hold cultural and aesthetic value for individuals worldwide (Arain et al., 2008). However, these sources are also vulnerable to the uncontrolled practises of waste disposal, which can facilitate the spread of disease-causing pathogens among humans. The assessment of water quality is imperative due to the fundamental necessity of ensuring the availability of safe and portable water for human consumption and the sustenance of aquatic organisms. This evaluation is conducted by examining both microbiological and physiochemical parameters. 2.0 MICROBIOLOGICAL/MICROBIAL PARAMETERS OF WATER QUALITY Microorganisms, despite their inconspicuous nature, are naturally present in various environments, including the intestinal tracts of humans, as well as streams and springs, which serve as natural habitats for their development and growth (Wiesman et al., 2007). The potential impact of these organisms on human health is determined by the form, type, and concentration of the pathogen. Bacteria, protozoa, and viruses have been recognised as the principal agents of microbiological water contamination, typically associated with the transmission of waterborne illnesses (Russel and Walling, 2007). Nevertheless, the presence of supplementary classifications of microorganisms, including worms, fungi, and helminths, although less commonly observed, exhibits a substantial degree of contamination. The evaluation of water quality based on microbial parameters involves the analysis of microorganisms, taking into account factors such as the type and abundance of microorganisms, as well as their presence in water bodies due to faecal contamination. The existence of faecal matter deposition serves as an indication of the decline in water quality, which is also a contributing factor to the discharge of detrimental toxins leading to various illnesses including gastrointestinal disorders, nausea, cramps, as well as waterborne viral diseases such as respiratory ailments (e.g., acute febrile respiratory illness, pneumonia, conjunctivitis). In the following discourse, we endeavour to examine various microorganisms and classify them according to their types, morphology, and abundance, thereby utilising them as a means to evaluate the quality of water. 2.1 Bacteria Bacteria can exhibit either unicellular or multicellular forms, which are determined by their varying degrees of diversity and complexity. According to APHA (2005) and Nathanson (2004), these organisms are classified as single-celled plants due to their cellular composition and their method of nutrient intake. Bacterial cells can be classified into three fundamental shapes: rod-shaped, also known as bacillus; spherical-shaped, also known as coccus; and spiral-shaped, also known as spirellus (Tchobanoglous et al., 1985). Some of the prevalent bacteria responsible for causing diseases include Salmonella spp. (specifically S. typhi and S. enterica). These bacteria are commonly transmitted through both human and animal hosts, including birds and farm animals. These microorganisms are commonly observed in conjunction with and are ingested either directly or indirectly via the consumption of water that has been contaminated, such as through sewage, water runoff, or the disposal of agricultural waste. Consequently, this can lead to the development of various diseases, including salmonellosis, gastroenteritis, and typhoid fever, among others. Mycobacterium avium complex (MAC), a bacterial species, primarily originates from aquatic environments and is transmitted through soil and pipe-borne water supply, leading to respiratory and gastrointestinal tract illnesses. Another example is Vibro Cholera, which is present in water sources originating from aquatic environments that may have come into contact with or passed through sewage tunnels or conduits, subsequently leading to the development of severe and potentially fatal illnesses such as cholera. It is important to acknowledge that certain bacteria have a metabolic requirement for oxygen, known as aerobic metabolism, while others are capable of carrying out their metabolic processes without relying on oxygen, known as anaerobic metabolism. Furthermore, it has been observed that bacteria exhibit reduced growth and reproduction rates at lower temperatures, whereas the opposite trend is observed at higher temperatures. Based on this hypothesis, it is anticipated that deep waters, characterised by lower temperatures, will exhibit reduced bacterial activity in comparison to surface waters. In order to ensure the suitability of surface waters for domestic use, it is imperative to subject them to appropriate treatment procedures due to the presence of these bacteria. 2.2 Virus Viruses constitute an additional category of pathogenic microorganisms. These entities represent the smallest biological structures currently identified as possessing the complete genetic material required for their own replication. They exist in various forms, including: Enteroviruses and Hepatitis A are primarily transmitted through human and pig faeces. These viruses can be found in sewage, septic tanks, and agricultural sewages, leading to the spread of diseases such as diarrhoea, meningitis, and infectious hepatitis. Adenoviruses are commonly detected in human faecal matter and are frequently transmitted through sewage systems, leading to the development of respiratory, urinary, and gastroenteritis ailments. Certain waterborne viruses can be rendered inactive through the disinfection procedures implemented in water treatment facilities. 2.3 Protozoa Protozoa are a distinct group of microorganisms, with certain species being commonly found among them. The Protozoans include; Cryptosporidium oocyst, which has been observed to be present in the faeces of both humans and various animals, including birds. The transmission of these faeces occurs via sewage systems and stormwater run-offs, resulting in the development of respiratory illnesses, hepatitis, and reactive arthritis. Microsporidia Encephalitozoonidae are frequently detected in the faecal matter of livestock, rabbits, mice, pigs, cows, goats, and other domesticated mammals. These microorganisms are transmitted through sewage systems and can lead to gastrointestinal disorders, respiratory infections, and reproductive infections. Giardia lamblia cysts can be detected in the faeces of humans, birds, domestic animals, and wild animals. These cysts have the potential to contaminate water bodies through various means such as sewage discharge and stormwater runoff. When consumed, either through direct ingestion or indirect means, these substances can lead to various illnesses such as abdominal cramps and Giardiasis. These protozoa have the ability to form cysts that often exhibit resistance to deactivation. PHYSICO-CHEMICAL PARAMETERS OF WATER QUALITY In addition to microbial or microbiological parameters, the assessment of water quality can also encompass intrinsic physico-chemical characteristics, including but not limited to Potential of Hydrogen (pH), Colour, Electrical Conductivity, Turbidity, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), and others. The anticipated attributes of these properties are anticipated to possess established values that verify the suitability of water quality for human consumption, industrial utilisation, and the sustenance of aquatic organisms. In this discourse, we shall endeavour to examine a selection of these characteristics and explore the diverse factors that exert an impact on the quality of water. 3.1 Turbidity Turbidity is commonly regarded as the quantification of the amount of light that is able to traverse a body of water, resulting from the existence of suspended substances such as clay, silt, organic matter, plankton, and other particulate matter within the water (Alley, 2007). The physico-chemical property of water is of utmost importance as it plays a crucial role in determining its suitability for human consumption and the ability of aquatic organisms to thrive in it. This suggests that as the turbidity of a water body increases, it becomes less aesthetically acceptable for human consumption due to the increased cost of water treatment for various purposes. The measurement of turbidity is conducted using a nephelometric turbidimeter, and the results are expressed in Nephelometric Turbidity Units (NTU) or Turbidity Units (TU). In general, groundwater exhibits lower turbidity levels in comparison to surface water due to the inherent natural filtration process that occurs as water molecules infiltrate through the pore spaces of soil (Spellman, 2017; Viessman and Hammer, 2004). Conversely, surface water tends to have relatively higher turbidity levels as it is subject to continuous disturbance and agitation. The implications of turbidity on water systems can be succinctly summarised as follows: There are several negative effects associated with the presence of suspended materials in water. Firstly, it leads to an increase in the cost of water treatment for various purposes (Davis, 2010). Secondly, it reduces the resistance of aquatic organisms, such as fish, making them more susceptible to diseases due to the damage caused to their gills by these suspended materials. Additionally, the presence of suspended materials leads to an increase in water temperature and a decrease in the concentration of dissolved oxygen (DO). Conversely, a decrease in water temperature results in an increase in the concentration of dissolved oxygen (DO). Lastly, these suspended particulates can serve as hiding places for harmful microorganisms, protecting them from the disinfection process (Edzwald, 2010). 3.2 Color The aforementioned is an inherent physical characteristic of materials found on Earth, such as minerals, soil, and rock. It is frequently employed in the process of identifying these substances. Earth materials are commonly observed to undergo diverse reactions, encompassing both biological and chemical processes, resulting in the transformation of these materials into either simpler or more refined forms. The colour of water can be influenced by the decomposition of both organic materials, such as vegetation and dead animals, and inorganic materials like soils, stones, and rocks. This process, known as decomposition or biological reaction, can have negative implications for both aesthetic and health-related concerns (APHA, 2005; Tommar, 1999). The assessment of water suitability for human consumption often relies on the analysis of colour, which is regarded as a fundamental parameter. The colour of water is considered a fundamental parameter in determining its suitability for human consumption. Specifically, water must exhibit both colorlessness (true colour) and colorfulness (apparent colour resulting from the presence of dissolved salts or suspended materials) in order to meet the required standards of purity. Therefore, it can be concluded that any water sample that displays a colour other than the true colour of water, known as apparent colour, is fundamentally unsuitable for human consumption. The purity of a water sample is assessed based on its colour, which is measured on a scale ranging from 0 to 70. A score of 0 indicates that the water is clear and pure, while higher scores indicate the presence of additional suspended materials. It is important to acknowledge, however, that this test does not provide a definitive determination of pure water, as certain salts may be present in a water sample and still yield a colourless result. Therefore, additional examinations must be conducted to verify the quality and purity of the substance, thereby ensuring its suitability for consumption. 3.3 pH (Potential of Hydrogen) The measurement of pH is a fundamental method for assessing water quality, as it enables the determination of the acidity or alkalinity of a water sample. This information is crucial for evaluating the suitability of water for both human consumption and the support of aquatic organisms. As per Hammer's (2011) research, pH is a numerical value that lacks units and serves as an indicator of the acidity or alkalinity of a solution. In essence, it can be stated that acidic water is characterised by an excess of hydrogen ions (H-), whereas basic water is characterised by an excess of hydroxyl (OH-) ions (Alley, 2007). Among the various physiochemical parameters, pH is widely recognised as the most significant physico-chemical factor that governs the dynamics of other water-quality parameters, including the concentration of metals in aquatic ecosystems (Weiner, 2008; Osotuyi et al., 2021a). Hydrogen ion concentrations have been observed to exert an influence on chemical processes occurring in aquatic systems, including acid-base reactions, solubility reactions, and oxidation-reduction reactions. The presence and availability of aquatic organisms, as well as the suitability of water for consumption, are generally influenced by the pH levels, which can be either high or low. The pH values of water exhibit a range spanning from 0 to 14, with a pH of 7 being designated as neutral. In contrast, a pH value below 7 signifies a state of heightened acidity, whereas values above 7 indicate the presence of a basic solution. According to the World Health Organisation (2011), water that is deemed suitable for human consumption and capable of supporting aquatic organisms should ideally have a pH level ranging from 6.5 to 8.5. In contrast, water that is considered clean and pure typically exhibits a pH level of 7.0 at a temperature of 25°C, which is commonly regarded as room temperature. On the other hand, rainwater tends to possess a pH level of approximately 5.6, indicating a slightly acidic nature. This acidity can be attributed to the dissolved atmospheric carbon dioxide gas that is present within the rainwater (APHA, 2005). The determination of water pH levels can be conducted using two different methods, namely electrometric or colorimetric techniques (APHA, 2005). Water bodies exhibiting elevated pH levels are typically indicative of a concurrent increase in oxygen concentrations, whereas decreased pH levels are commonly attributed to the presence of dissolved salts, corroded metals, and chemical substances such as cyanides and sulphides. It is worth noting that these dissolved substances tend to become more toxic as they dissolve more readily. In a study conducted by Malecki et al. (2017), it was demonstrated that different municipal water suppliers choose to analyse the pH levels of their water sources in order to effectively monitor and control the presence of pollutants. This finding highlights the significance of pH as a fundamental instrument for identifying areas of contamination within bodies of water. 3.4 Electrical conductivity (EC) The assessment of water's appropriateness for domestic, aquatic, or industrial purposes often includes the consideration of electrical conductivity as a significant parameter. Water body conductivity refers to its capacity to carry an electrical current, which can also be described as the inverse of resistivity. This suggests that there is an inverse relationship between the resistivity and conductivity of a medium, such as water, whereby higher resistivity corresponds to lower conductivity and vice versa. According to Tchobanoglous et al. (2003), Electrical Conductivity (EC) is a quantification of the capacity of a solution to transport or conduct electric current or charges. The electrical conductivity (EC) of a water sample has been observed to exhibit a positive correlation with the concentration of ions present. Consequently, EC serves as a valuable parameter for assessing the quality of water. The measurement unit for conductivity is milliSiemens per metre (mS/m) or deciSiemens per metre (dS/m). Pure water, which is devoid of dissolved salts, is commonly recognised as a poor conductor of electricity. In contrast, water found in seas and oceans typically exhibits electrical conductivity values of approximately 5S/m. In regions where an aquifer is fully saturated with water, the presence of dissolved solids, dissolved chemicals, leachates that have infiltrated through the pore spaces, and minerals derived from weathered rocks (Osotuyi et al., 2022; Zhang et al., 2022; Song et al., 2022; Osotuyi et al., 2023) can potentially impact the conductive properties of both the water and the aquiferous formation (Falebita et al., 2018;