Environmental Pollution and Public Health: Case Studies on Air, Water and Soil from an Interdisciplinary Perspective

Environmental Pollution and Public Health: Case Studies on Air, Water and Soil from an Interdisciplinary Perspective provides detailed case studies showing real-world applications of the latest technologies surrounding pollution in air, water and soil. Sections cover the environment and its nexus with public health, highlighting how the health of our environment can invariably influence our public health. Following this, atmospheric pollution is addressed, identifying various air pollutants, methods for identification, impacts on the environment and health, and mitigating technologies. Final sections are dedicated to liquid waste management, focusing on wastewater and treatment options including emerging technologies that are compared to existing options.

The book finishes with case studies and information on regulatory frameworks for environmental pollution for those wanting to implement the remediation techniques covered. This is a necessary read for postgraduates, academics, professionals and researchers in environmental science, soil science, environmental health, and waste management who need the latest sustainable remediation practices and case studies and the efficacy of the associated techniques.

• Offers a broad overview of the environmental and practical aspects of pollution, pollution control measures, and environmental impact assessment
• Focuses on providing detailed, global case studies with an emphasis on cost, efficiency and sustainability of the techniques for treating wastewater, contaminated soils and solid waste
• Provides theoretical and technical information that will assist professionals and practitioners in their goals to address current challenges stemming from environmental pollution

• Language: English
• Publisher: Elsevier Science
• Release date: Jan 15, 2024
• ISBN: 9780323959681

Book preview

Part 1

The environment and its critical nexus with public health

1 Bacterial and viral contaminants in drinking water: Why do they really matter to us 3

2 The health of our environment and Sustainable Development Goal 3 29

Chapter 1

Bacterial and viral contaminants in drinking water: Why do they really matter to us

Blessing I. Nwadike, Olutayo I. Falodun and Adeniyi A. Ogunjobi

Department of Microbiology, Faculty of Science, University of Ibadan, Ibadan, Nigeria

1.1 Introduction

The main challenge to water security is embodied in water pollution. Water pollution refers to the change in the normal composition of water as a result of the deposition or presence of foreign substances in such water (Cheesbrough, 2010). However, these foreign substances arise from diverse sources such as urbanization, industrialization, agricultural, and anthropogenic activities (Meybeck, 2003). It is important to note that these foreign materials make water scarce and unavailable as potable water for humans. The extraneous materials in water come along with loads of bacterial and viral contaminants that endanger public security and as well as animal lives (Ogunjobi, 2017). All plants, humans, and animals need water to survive. There can be no life on earth without water. Why is water so important? Water is essential for life right from the time that primeval species ventured from the oceans to live on land, a major key to survival has been the prevention of dehydration. Without water, humans can survive only for days. Water comprises 75% of body weight in infants to 55% in the elderly and is essential for cellular homeostasis and life (Nicolaidis, 1998). Nevertheless, there are many unanswered questions about this essential component of human body and our diet. All cells, organ, and tissues in the human body use water to help regulate temperature and maintain other functions. We lose water from our bodies through breathing, sweating, urinating, and digestion. It is crucial to rehydrate and replace water in the body by drinking fluids and eating foods that contain water. Staying hydrated is critical to maintaining a normal body temperature. Our bodies lose water when we sweat in hot environments. Sweat keeps our bodies cool, else our body temperatures will go up if we do not replenish the water we lose (Climate Change, 2022). Lack of water causes dehydration, which in turn causes levels of electrolytes and plasma to drop. Proper hydration is crucial to staying in good cognitive shape. Research has shown that inadequate water intake can negatively impact our focus, alertness, and memory. Water helps lubricate and cushion our joints, spinal cord, and tissues. This helps us to be more physically active and reduces the discomfort caused by conditions such as arthritis. Getting enough water every day is important for health. Drinking water can prevent dehydration, a condition that can cause unclear thinking, result in mood change, cause the body to overheat, and lead to constipation and kidney stones.

Drinking water must be potable (free from harmful substances and pathogens) for it to give the necessary benefit to the body (Ogunjobi, 2017). The amount of water a body needs depends on a variety of factors: the climate a person lives in, how physically active people are, and whether the body is experiencing an illness or has any other health problems; all affect recommended water intake by an individual (Climate Change, 2022). The amount of water needed each day varies from person to person, depending on how active they are, how much they sweat, urinate, and so on. No fixed amount of water must be consumed daily, but there is general agreement on what a healthy fluid intake is. Generally, water intake (from all beverages and foods) that meets most people's needs is about 15.5 cups of water each day for men; about 11.5 cups daily for women (Kummu et al., 2016). People get about 20% of their daily water intake from food. The rest is dependent on drinking water and water-based beverages. Ideally, men would consume about 3.0 liters of water from beverages and women, about 2.12 liters from beverages. In order to avoid dehydration, people exercising or living in a hotter region should increase their water intake. With this water intake by humans, it becomes very clear that safe water must be available for consumption. But in reality, safe water is scarce in the world. As a result, some 1.1 billion people worldwide lack access to water, and a total of 2.7 billion find water scarce for at least one month of the year. Inadequate sanitation is also a problem for 2.4 billion people, thus they are exposed to diseases such as cholera and typhoid fever, and other water-borne illnesses. Two million people, mostly children, die each year from diarrheal diseases alone which are related to inadequate safe water for domestic and drinking purposes (WHO, 2022).

Many of the water systems that keep ecosystems thriving and feed a growing human population have become stressed. Rivers, lakes, and aquifers are drying up or becoming too polluted to use. More than half the world's wetlands have disappeared. Agriculture consumes more water than any other source and wastes; much of that through inefficiencies. Climate change is altering weather and water patterns around the world, causing shortages and droughts in some areas and floods in others. At the current consumption rate, this situation will only get worse. By 2025, two-thirds of the world's population may face water shortages and ecosystems around the world will suffer even more.

Water scarcity, closely related to water stress or water crisis, is the lack of freshwater resources to meet the standard water demand. There are two types of water scarcity: physical and economic water scarcity (Rijsberman, 2006). Physical water scarcity is where there is not enough water to meet all demands, including that needed for ecosystems to function effectively. Arid areas (for example Central Asia, West Asia, and North Africa) often suffer from physical water scarcity. On the other hand, economic water scarcity is caused by a lack of investment in infrastructure or technology to draw water from rivers, aquifers, or other water sources, or insufficient human capacity to satisfy the demand for water (IWMI, 2007). Much of sub-Saharan Africa has economic water scarcity (Postel et al., 1996).

The essence of global water scarcity is the geographic and temporal mismatch between freshwater demand and availability (Mekonnen and Hoekstra, 2016; Savenije, 2000). At the global level and on an annual basis, enough freshwater is available to meet such demand, but spatial and temporal variations of water demand and availability are large, leading to physical water scarcity in several parts of the world during specific times of the year (Liu et al., 2017; Rabiu et al., 2022).

Investment in water security is a long-term payoff for human development and economic growth, with immediate visible short-term gains. Significant upfront investments may be required, but these will pay off in the long term through better institutions, increased capacity, improved levels of human well-being, environmental sustainability, economic production, and reduced conflicts. In the short term, water security can lead to increases in employment and education opportunities, especially for women and girls who often bear the brunt of responsibility for collecting water. In the long term, it results in reductions in healthcare spending, productivity losses, and labor diversions (UNDP, 2006). Investments in water security—including water services, capacity building, good governance, the maintenance of water-related ecosystem services, and natural infrastructure—mitigate the need for corrective measures and to some extent, the need for significant funds funneled through channels such as development aid (Ogunjobi, 2017)

Water security may be defined as the sustainable use and protection of water resources, safeguarding access to water functions and services for humans and the environment as well as protection against water-related hazards such as flood and drought (Cook and Bakker, 2012). Water security is defined here as the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socioeconomic development, for ensuring protection against water-borne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability (Allen, 2011).

More important to water security is the contamination of supposedly available clean water with bacterial and viral particles. The fact that water is free from peculiarities of odor, color, and taste does not imply that the water is good enough for human consumption. Groundwater has been the source of drinking water for many African villages and towns to date as it was in the United States in the past. A documented report indicated the reliance of the United States on groundwater before it was discovered that without proper treatment, groundwater is not actually safe. Groundwater supplies more than 100 million Americans with their drinking water (USEPA, 2000); in rural areas, there is an even greater reliance on groundwater, which comprises up to 95% of the water used (Bitton and Gerba, 1984). Traditionally, it has been assumed that groundwater is safe for consumption without treatment because the soil acts as a filter to remove pollutants. As a result, private wells generally do not receive treatment (Foreman et al., 1993), nor do a large number of public water supply systems. The U.S. Environmental Protection Agency (USEPA) estimated that approximately 72% of the 158,000 public water supply systems in the United States that use groundwater do not disinfect it (USEPA, 1990). However, the use of untreated contaminated, or inadequately treated groundwater has been the major cause of waterborne disease outbreaks in the United States since 1920 (Barwick et al., 1999; USEPA, 2000). Historically, groundwater containing bacteria and viruses has been responsible for approximately half of the reported waterborne disease outbreaks in the United States. This clearly indicated that the presence of bacterial and viral pathogens really matters in our drinking waters. It is believed that drinking water containing chemical impurities, be it heavy metals or others is better to be consumed than one containing a small amount of pathogenic microorganisms.

1.1.1 Scarcity of drinking water

According to WHO (2022), one of the Sustainable Development Goals (SDG) is clean water and sanitation; this calls for universal and equitable access to safe and affordable drinking water. This task is monitored with the index of (safely managed drinking water services) drinking water from an enhanced water outlet/source located on-premises, readily obtainable when needed, and unconstrained from fecal and priority chemical contamination. Over 2 billion people live in water-stressed countries, which is expected to be worsened in some regions due to climate change and population increase (WHO, 2022). The report opined that at least 2 billion people globally utilize drinking water sources/outlets contaminated with feces; thus, microbial contamination of drinking water with feces poses the greatest risk to drinking water safety. Arsenic, fluoride, and nitrate with emerging contaminants such as pharmaceuticals, pesticides, and microplastics are the most important chemical risks in drinking water.

Access to safe drinking water brings about a reduction in adverse health effects. According to World Health Organization (WHO), the UN General Assembly explicitly recognized the right to water and sanitation in 2010; thus, every individual has the right to sufficient, continuous, safe, acceptable, physically accessible, and affordable water for personal and domestic use (WHO, 2022). One aspect which the developed countries have prioritized is the provision of safe drinking water to their people and it is the most successful public health intervention for humanity (Ashbolt, 2015). Nevertheless, unnecessary waterborne disease outbreaks in wealthy communities are caused by ignorance of the potential risks of the diseases and inappropriate training of people working in water treatment systems (Hrudey and Hrudey, 2014). The quality of groundwater is compromised by indiscriminate waste dumping and leachate percolation in the environment.

1.1.2 Water pollution

Water pollution is a global problem that causes diseases and deaths on a daily basis. Water pollution is when water contains substances that render the water unfit for human consumption and reduces its economic value. Developed and developing countries face water pollution problems. Many factors such as precipitation, climate, soil type, vegetation, geology, flow conditions, and human activities influence water quality (Chaudhry and Malik, 2007). Water pollution can occur from two sources, namely: point sources and nonpoint sources. Point sources of pollution are those sources that are direct and can be identified. It includes pipe attached to a factory, oil spills from a tanker, effluents from industries, wastewater from a wastewater treatment facility. Nonpoint sources of pollution are those that are from different origins and nonidentifiable sources which include runoff from agricultural fields and this is difficult to regulate as there is no single identifiable body to be held responsible. Pollution occurs from either point source or nonpoint sources and the greatest threat to water quality is caused by industrial and municipal point sources. Sediments, nutrients, and toxic contaminants amount to nonpoint sources of water pollution (Florescu et al., 2010). As a result of this, pure water is becoming scarce day by day and the most important cause of water pollution is industrialization and population increase. This widespread problem of water pollution is jeopardizing human health. Owing to the advancement of technology and industrial growth, freshwater resources all over the world are threatened (Sharma and Bhattacharya, 2017).

1.1.3 Contaminants in water

The Safe Drinking Water Act (SDWA) defines the term contaminants as any physical, chemical, biological, or radiological substance or matter in water. Therefore, contaminant refers broadly to anything other than water molecules. Drinking water may reasonably be expected to contain at least small amounts of some contaminants. Some drinking water contaminants may be harmful if consumed at certain levels while others may be harmless. The presence of contaminants does not necessarily indicate that the water poses a health risk (USEPA, 2021); rather a contaminant's effect on water is dependent on the water characteristics and also the quantity/amount of the contaminant and its characteristics.

All water contains natural contaminants, particularly inorganic chemicals that spring from the geological strata through which the water flows, and anthropogenic pollutants to a varying extent (Fawell and Nieuwenhuijsen, 2003). Only a small number of the universe of contaminants are listed on the Contaminant Candidate List (CCL). The CCL serves as the first level of evaluation for drinking water contaminants that may need further investigation of their potential health effects. The quantity of contaminants reaching water sources is determined by many factors including land management practices, watershed characteristics, chemical properties of the contaminant, and the amount of the contaminant that is released to the environment. Events such as wildfires and floods may also impact the amount of contaminants in water sources. Some contaminants in drinking water can easily be identified by assessing color, odor, turbidity, and taste; however, most cannot be easily detected and require testing to show whether the water is contaminated (Sharma and Bhattacharya, 2017). The color of drinking water is a physical characteristic and its intensity cannot be noticed unless it is of high concentration; odor on the other hand is an indication of the presence of some contaminants, though odor-free water is not necessarily safe for drinking purposes. The presence of clays, silt, and sand or organic materials results in turbidity, and this turbidity may shield bacteria and prevent disinfection chemicals from acting and destroying the cells.

Basically, the contaminants associated with pollution are four types namely: inorganic contaminants, organic contaminants, biological contaminants, and radiological contaminants.

I. Inorganic contaminants: This primarily impacts the physical appearance or other physical properties of water and their presence can be measured by the chemical parameters. The hardness of drinking water is a naturally occurring contaminant that depends on the geological status of the water source. Several inorganic substances such as fluoride, copper, chromium, mercury, antimony, and arsenic contaminate water resources and they get into water from industrial processes, natural sources, and also from plumbing systems (EPA US, 2006; Nriagu, 1988). Globally, chemical contamination of drinking water puts more than one billion people at risk of adverse health effects; and the resource-constrained communities are the most endangered and confronted with unique challenges that require innovative safe water solutions (Amrose et al., 2020). The communities mostly affected by chemical contaminants in drinking water are socioeconomically disadvantaged and marginalized communities whether in high-income or low- and middle-income countries. This is as a result of a complex set of factors like increased human physical exposure to the water body, reduced likelihood that the water will be tested and treated, poorer health outcomes due to reduced health care access, and high underlying burden of malnutrition and disease (Flanagan et al., 2016; McFarlane and Harris, 2018).

Effects of some of the inorganic contaminants include:

• Fluoride: The source may be geological or anthropogenic. There may be weathering of fluoride-bearing minerals on the earth's crust which can lead to increased fluoride levels in groundwater as the geological source; while anthropogenic sources are some pharmaceutical products, insecticides, medicines, preservatives, superphosphate fertilizers, and others that enter the water body (Sharma and Bhattacharya, 2017). Fluorides affect children and the elderly. They are implicated in the cause of dental and skeletal fluorosis, Alzheimer's disease, and other kinds of dementia (Fawell et al., 2006; Susheela, 1999; WHO, 2008).

• Arsenic: Drinking water contaminated with arsenic can cause arsenicosis (Chen et al., 1988); and arsenic enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices (Smith et al., 2000). Arsenic has been implicated in cancer of the skin, liver, prostate, bladder, and lungs (Yoshida et al., 2004). Noncancer effects can include thickening and discoloration of the skin, numbness in hands and feet, partial paralysis, nausea, and blindness.

• Mercury: It gets into drinking water from agricultural runoff as well as seepage from factories and landfills. Drinking water contaminated with mercury has been implicated in the impairment of brain functions, neurological disorders, abortion and disruption of the endocrine system, and retardation of growth in children (Clarkson, 1992; Counter and Buchanan, 2004).

II. Organic contaminants: Drinking water contaminated with organic materials can cause serious health challenges like hormonal disruptions, cancer, and nervous system disorder. The major anthropogenic sources of these contaminants are domestic waste, industrial waste, dyes, and pesticides. Pesticides enter into the water through agricultural activities as well as their improper handling and procedures. Dyes are of great environmental concern as they are the source of nonappealing pollution and can lead to the production of dangerous by-products.

Also, of great importance are the emerging organic contaminants such as pharmaceuticals, industrial compounds like hydrocarbons, personal care products, and water treatment by-products which are capable of causing adverse ecological or human health effects.

III. Biological contaminants: In developing countries, the most common and deadly pollutants in drinking water are of biological origin. These biological agents are living organisms like bacteria, viruses, algae, and protozoan; each with its distinctive problems in the water. For instance, the presence of algae in the water is controlled by the quantity of nutrients (phosphorus) which is generally from domestic runoff or industrial pollution. The excessive growth of algae imparts on the odor and taste of water because, at times, the algae release toxins into the water that can damage the liver, skin, and nervous system when taken (Hitzfeld et al., 2000; Rao et al., 2002). Infectious diseases caused by pathogenic bacteria, viruses, protozoa, and parasites are the most common and widespread health risks associated with drinking water (Gadgil, 1998). The contamination of drinking water by pathogens causes diarrhea and other waterborne diseases.

IV. Radiological contaminants: These contaminants enter into drinking water through soils or rocks that the water passes through, or from industrial waste. It can also be a result of erosion of natural deposits of radioactive materials that can emit radiation and these contaminants increase the risk of cancer. The different categories of the contaminants and their examples are listed in Table 1.1.

Table 1.1

1.2 Microorganisms associated with water

Good drinking water is indispensable for life and it is also a vital human right. However, according to the estimation of WHO, about 700 million people globally have been reported to source their drinking water from unacceptable sources because they do not have access to clean and safe drinking water. This has resulted in a negative health effect on their life quality and even the death of many people as a result of waterborne microbial infections. Microbial pathogens such as bacteria, viruses, protozoa, and helminths are varieties of microbial pathogens that can be transmitted through contaminated drinking water. These pathogens are also the causative agents of waterborne illnesses. The important sources of microbial water contamination are humans, animals, and birds’ feces which can invariably be a good source of pathogenic microorganisms (WHO, 2017).

Contamination of water with waterborne pathogenic microbes and related diseases is of great concern throughout the world for water consumers in terms of the quality of drinking water. According to the WHO estimate, about 25% of the world's population consumes water that is contaminated with fecal matter (WHO, 2014). Each year, waterborne disease outbreaks (WBDOs) associated with recreational water, treated drinking water, and treated and untreated groundwater are reported. The actual cause of water contamination with microbial pathogens varies greatly and is dependent on the source of the water. However, the two most important sources of contamination can be fecal material introduction into the water source, drinking water that is inadequately treated, or interruption of the treatment process (Craun et al., 2006).

Several microorganisms that are well-known to be associated with water contamination as well as causing varieties of waterborne diseases and epidemics in humans include bacteria, viruses, parasites, protozoa, and fungi. The most notable disease caused by these waterborne pathogens is gastroenteritis (Pandey et al., 2014).

Water plays an important role in the transmission of a lot of pathogenic microorganisms through direct contact with or by consuming water that is contaminated with pathogenic microorganisms; transmission of which could lead to waterborne infections. In most developing countries of the world, waterborne diseases constitute public health challenge because a vast majority of the population residing in their rural areas obtains their water supply from streams that are not protected as well as groundwater. Diarrhea, the second global leading cause of death in children under the age of five has a direct link with water that is unsafe for consumption, insufficient sanitation as well as poor hygiene. Those living in poverty in the rural areas of the low-income countries of the world constitute the high-risk group of waterborne infections. However, those living in developed countries with state-of-the-art water and waste treatment facilities are also liable to outbreaks of waterborne diseases. Hence, no matter what the socioeconomic status of a country might be, illnesses as a result of water contaminated with microbial pathogens are very significant and grossly underreported. This is because medical attention for infections that are self-limiting is not being sought coupled with the limitations and difficulties in clinically detecting some of the infections, especially those caused by viruses.

1.2.1 Protozoans

Protozoan parasites are one of the most important causes of waterborne diseases and have been identified as the second most frequent aetiological agent of mortality among children less than five years of age (Efstratiou et al., 2017). Some protozoan parasites of health significance include: Cryptosporidium sp., Cyclospora cayetanensis, and Giardia lamblia; they are responsible for emerging cases of contaminated water (Céline et al., 2009). All over the world, protozoan parasites are identified to be responsible for over 1.7 billion diarrhea cases out of which 842,000 deaths per year are recorded (Efstratiou et al., 2017). So many waterborne outbreaks due to cryptosporidiosis have been reported globally with the first being C. cayetanensis waterborne outbreak that was described in 1990. After this report, the confirmation of C. cayetanensis, Microsporidia, Isospora belli, and C. parvum detection in drinking water was reported by WHO (Ortega and Sanchez, 2010; WHO, 2011).

The challenge of epidemic and endemic diseases which was as a result of parasitic infection transmitted through water by protozoa is not limited to the developing countries alone but is also a problem of the developed world as well. However, the hygiene conditions in the latter are better, hence, parasitic protozoa are commonly not regarded as a reason for the diseases. In the former, both the treated and untreated water are consumed resulting in higher rates of diseases caused by protozoan parasites despite that water treatment standards have been achieved (Mtapuri-Zinyowera et al., 2014). Giardia spp. and Cryptosporidium spp. are parasitic protozoa that cause infection in a wide range of vertebrates including humans. The transmission of the infection of these parasites is through the fecal-oral route resulting from either direct or indirect contact when water and/or food contaminated with the parasites are consumed, or when there is direct contact with people that are infected from feces.

Infections with these protozoans are of public health relevance because they have been implicated in waterborne diarrheal diseases such as giardiasis and cryptosporidiosis whose cases have been on the increase in recent years (Ćirkovića et al., 2020; Silva et al., 2021). For instance, at least 381 outbreaks of (oo)cysts of Giardia spp. and Cryptosporidium spp. transmitted through treated water were reported from the year 2011 to 2016 in Zealand, North America, and Europe (Efstratiou et al., 2017).

Although, cases of giardiasis and cryptosporidiosis are underreported in some countries like Brazil, where reporting such infection was considered not to be compulsory, hence, diseases caused by these protozoans are not notified. However, a number of infected people have been reported. In addition, (oo)cysts of both the Giardia spp. and Cryptosporidium spp. have been detected in surface water in different cities in Brazil and other regions worldwide (Nakada et al., 2019; Oliveira, 2017; Silva and Scalize, 2020). Some of the reasons why the outbreaks of the (oo)cysts of these protozoa occurs include: their high infectivity, resistance to environmental conditions, and treatment of conventional chlorination. As a result of these, control of waterborne diseases caused by protozoa are very difficult since many of the pathogens such as Cryptosporidium are highly resistance to many of the traditional processes employed in water disinfection.

Some notable parasites that are associated with drinking water contamination include:Giardia and Cryptosporidium. Giardia is a parasite responsible for diarrheal disease called giardiasis and are commonly found in soil, food or water that has been previously contaminated with feces from infected humans and animals. Infection can occur when water that contains the parasite is consumed and can also be transmitted from one person to another via contaminated water, foods and objects. The most common means of infection transmission is through the consumption of contaminated drinking water or recreational water such as lakes, rivers, or pools. Cryptosporidium which is one of the leading waterborne pathogen is a parasite that is responsible for cryptosporidiosis which is a disease of both humans and animals. The parasite contains an outer protective shell that enables it survive long outside the body and hence, able to tolerate disinfection with chlorine. Although, the parasites can be transmitted through many ways, the most common means of transmission is either drinking or recreational water.

1.2.2 Fungi

Fungi consist of diverse groups of organisms that belong to the kingdom Eumycota which also comprises of five phyla including Ascomycota, Basidiomycota, Zygomycota, Chytridiomycota, and Glomeromycota. Fungi are classified into filamentous fungi (also referred to as molds), yeasts and mushrooms. There are some fungi that have adaptations to the aquatic environments and are naturally found in water; they are zoosporic and many are of the phyla Chytridiomycota. Primarily, fungi that belongs to other phyla such as Eumycota are adapted to terrestrial environments such as soil, organic material, and air, as well as anything that has contact with air (Kirk et al., 2001).

In the past, fungi were normally not being considered in the evaluation of microbial pathogens in water. This is because consuming drinking water contaminated with fungi is not linked to acute disease unlike some other microbial contaminants such as bacteria, viruses and parasites which their occurrence are commonly associated with relatively acute diseases with symptoms in humans. Although, the presence of fungi in drinking water has mostly been ignored, it may be considered as a chronic problem in the distribution channel and perhaps has been a problem that is being taken too lightly. However, in the last two decades, increased attention has been focused on fungi as contaminants of drinking