Water is a resource that is precious and vital to the existence of all living organisms, but this cherished resource is increasingly being threatened as human populations grow and demand more water of high quality for domestic purposes and economic activities (Yakubu, 2013). Man must always have an adequate supply of potable water for his various daily needs (Ochuko et al., 2014). Specifically, man needs water for drinking, cooking, bathing, washing, agricultural purpose, manufacturing and industrial purposes. Water is equally used for the disposal of sewage. In the developed nations of the world, the average domestic use of water including that for all purposes per person is 180-230 litres per day. An average daily use per person of 450 litres is not uncommon particularly in the highly industrialized countries. While in Nigeria, the average domestic consumption by individual is 2.25 litres per day as against 115 litres per head per day by the World Health Organisation (Nkemdirim and Iroegbu, 2009).
Safe drinking water is a human birth right as much as clean air, however much of the world’s population does not have access to safe drinking water (Adefemi, 2012). Inadequate water supply is still one of the major challenges in developing countries (Bakobie et al., 2012). It has been reported that 783 million people in the world (11% of the total population) have no access to safe water, 84% of them live in rural areas (WHO and UNICEF, 2012). About 187 million people use surface water for drinking purposes, 94% of them are rural inhabitants and they are concentrated in sub-Saharan Africa (WHO and UNICEF, 2012).
However, safe drinking water remains inaccessible for about 1.1 billion people in the world and the hourly toll from biological contamination of drinking water is 400 deaths of children below the age five (Gadgil, 1998). Water helps maintain the moisture of internal organs of the body, maintains normal volume and consistency of fluids such as blood and lymph regulates body temperature; removes poisons or toxins from the body through urine, sweat and breathing and is essential for regulating the normal structure and functions of the skin (Gerald, 2011).
Many water resources in deprived nations are detrimental because they harbour harmful physical, chemical and biological agents. Total coliforms and E. coli are used as indicators to assess the degree of contamination and sanitary quality of well water, because testing for all known pathogens is a problematic and expensive process (Nkansah et al., 2010). The scarcity of piped water has made communities to find alternative sources of water such as hand dug well water and rainwater (Bakobie et al., 2015).
Hand dug well is generally less susceptible to contamination and pollution when compared to surface water bodies (Babakobie et al., 2015). However, rural dwellers hold a theoretical view that groundwater being the “safest” water; wells are found to be polluted in terms of mineral contents, particles solute, organic matter and bacteria concentration (Babakobie et al., 2015). Hand dug well water contaminations are attributed to anthropogenic activities such as disposal of domestic, municipal and industrial waste on the land surface, in shallow excavation including septic tanks, deep wells and agricultural chemicals leach into tanks and pipelines (Adekunle, 2008). Ground water accounts for about 98% of the world fresh water that is distributed throughout the world (Ayodele and Aturamu, 2011). The preference of hand dug well water as a source of drinking water in rural areas is because of its relatively better quality than river water (Obiri-Danso et al., 2009). Almost one third of the population in Asian and African cities (both in urban and rural areas) use well water as a main source of drinking water (Subin and Aneesha, 2011), most of which are unprotected and sited close to septic tanks (Mulenga and McGranahan, 2011).
Graham and Polizzotto (2013) observed that septic tanks are one of the most common human excreta disposal systems in developing countries, and their use is on the rise as countries aim to meet the sanitation-related target of the Millennium Development Goals. Hand-dug wells are usually shallow, about 20m or less and water from this source is used directly without treatment and could be faecally contaminated due to inadequacy of proper toilet facilities (Olayinka et al., 2014). Most pit latrines were poorly constructed and lack physical barrier, such as concrete, between stored excreta and soil and/or groundwater (Almansi et al., 2010) thus creating serious health risk (Hendriksen et al., 2012). Olayinka et al. (2014) discussed that soakage pits and pit latrines can extend their influence on groundwater quality up to 10m or more as groundwater flow is either lateral or vertical. It is easy for excreta from the pit latrines to leach into nearby hand-dug wells, thereby threatening human health through well-water contamination. It affects the physicochemical and bacteriological components of the water leading to infectious diseases. Inadequate sanitation, water supplies and poor hygiene are critical determinants for diarrhoeal diseases and infectious diseases transmitted by the faecal-oral route (Nostrom et al., 2013).
Safe drinking water is a basis human requirement and is essential to all. Contaminated drinking water has the greatest impact on human health worldwide, especially in developing countries (Momba et al., 2010). A study in 2002 especially in developing countries (Momba et al., 2010) outbreak of human illness associated with the consumption of contaminated water have been reported from many counties (Cabral, 2010). A study in 2002 estimated that water, sanitation and hygiene were responsible for 4.0% of all deaths and 5.7% of the total disease burden occurring worldwide (Rafman et al., 2011). Diarrhea disease alone cause 2.2 million of the 3.4million water-related death per year. Many of the death involve children less than five years of age. In developing countries, four-fifths of all the illness are by water borne disease, with diarrhea being the leading cause of childhood death, (Rahman et al., 2011). As a developing country, Nigeria is not an exception. In Nigeria, water-related diseases are responsible for 24% of all deaths. Every year, gastroenteritis and diarrhea disease kill 110,000 children below the age of five. Waterborne diseases account for nearly a quarter of all illnesses in Nigeria, while about 12% are accounted for, by diarrhea and 10% by other gastrointestinal illness including enteric fever. Thus water plays a major role in the overall disease profile of the country (Noosorn and Niamkamnerd, 2009).
Escherichia coli (E. coli) infections usually result when water and/or food contaminated with the bacterium is consumed. The general symptom of the infection is mostly diarrhea, which can cause death in immuno-compromised individuals such as the very young and the elderly, due to dehydration from prolonged illness (Kinge et al., 2010). E. coli O157:H7 is one of the E. coli strains which is now well-recognized as a cause of serious, and sometimes fatal, human illness. Despite the fact that E. coli infections are linked to consumption of infected dairy products such as raw cow milk, different sources of infection have been implicated, including leafy vegetables and water (Mead and Griffin, 1998). In the United States, the first reported drinking water outbreak of E. coli infections occurred in 1989 in rural Missouri (Swerdlow et al., 1992). Since this outbreak, many others have been associated with drinking water (Brunkhard et al., 2005). These outbreaks have led to the increased use of antibiotics to treat infections. The use of antibiotics in medicine and their applications in animal husbandry has brought about phenotypic changes, often due to chromosomal mutations, and antibiotic resistance in E. coli has been globally identified in isolates from environmental, animal and human sources (World Health Organisation, 2014).
Kinge et al. (2010) report that E. coli has been linked to well-known antibiotic-resistant gene pools and that these genes are transferred into the normal flora of humans and animals, where they exert a strong selective pressure for the emergence and spread of resistance in E. coli strains. Inevitably, they discover their route into nature’s turf through wastewater, compost and sewage slime. In much of the developing world without access to good quality medicines, infections continue to be the major killers, and in all countries, infections with resistant microorganisms are a major cause of death (World Health Organisation, 1999).
Public concern about microbial water quality and the need to understand the occurrence of bacterial pathogens in surface water systems is evident, particularly following waterborne outbreaks of enteric disease (Kondro, 2000). While the use of untreated surface water for drinking is high in the general population, contamination of public water supplies by surface water containing E. coli and other pathogens has been reported (Barwick et al., 2000).
Aim of the Study
The study investigates the isolation and prevalence of Escherichia coli in well water close to latrine.
Objectives of the Study
i. To isolate Escherichia coli from well water samples close to latrine
ii. To identify the isolates using standard biochemical tests
iii. To determine the microbial load of the well water samples