CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 Assessment of Water Quality
In a well- balanced aquatic ecosystem, the quality of water plays a critical role between, the organisms and environment which is also extremely important for the health of the ecosystem (Akbulut et al., 2010). In water quality assessment the microbial community has special significance, especially in terms of protecting public health. Coliform bacteria, normally present in intestinal tract of humans and worm- blooded animals, can secondary be found on plants, in the soil and in waters. Although the occurrence of primarily non- pathogenic refers to the presence of disease- causing organisms, they reach natural waters mainly during rainfall, through runoff from agricultural and urban lands, as well as through drainage (Radojevic et al., 2012). Total coliform (TC) is used as a parameter giving basic information on microbiological quality of surface waters (WHO, 2008). For more than a century the presence of coliform bacteria in drinking and recreational waters has been taken as an indication of fecal contamination, and thus of a health hazard. Total coliform and thermotolerant (fecal) coliform (FC) indicator tests are common public health tests of the safety of water and wastewater which might be contaminated with sewage or fecal material (APHA, 2008).
Historically, water has played a significant role in the transmission of human disease. Typhoid fever, cholera, infectious hepatitis, bacillary and amoebic dysenteries and many varieties of gastrointestinal diseases can all be transmitted by water (Rompre et al., 2012).
The qualitative and quantitative composition of fungi in water sediments depend on the origin and composition of waste water sediments, stabilization degree of their organic matter, hydration degree and structure. It was postulated that keratinophilic fungi may be utilized as microbiological indices for the transformations of organic matter of waste water sediments as well as of the degree of their deactivation from the sanitary standpoint (Ulfig and Korcz, 2011).
Drinking water is worldwide the most important single source of gastroenteric diseases, mainly due to the faecally contaminated raw water, failures in the water treatment process or recontamination of treated drinking water (Medema et al., 2013a; World Health Organization, 2013a). Two thirds of the total drinking water consumed worldwide is derived from various surface water sources (Annan, 2010) that may easily be contaminated microbiologically by sewage discharges or faecal loading by domestic or wild animals or whose microbial quality may be endangered by various weather conditions. Surface waters are also widely used for leisure and recreational activities, and thus unintended ingestion of microbiologically contaminated water poses a potential health risk (Cabelli et al., 2007; Asperen van et al., 2008; Stuart et al., 2013; Schönberg-Norio et al., 2014).
Treated or untreated surface water is also one of the main sources of drinking water under field and emergency conditions (Backer, 2012; Townes, 2012; Boulware et al., 2013). A minimum of two litres of safe drinking water should be available per person daily to compensate for the water lost in urine, faeces or perspiration (North Atlantic Treaty Organization, 2012). During physical exercise, compensation for lost fluid is essential to maintain physical and mental activity (Armstrong et al., 2007; Noakes et al., 2007). Unsafe or contaminated drinking water may infect and incapacitate not only individual persons but also large groups, thus prohibiting them from fulfilling their tasks (Aho et al., 2007; Blaisdell, 2007; Cook, 2011; Boulware et al., 2013; Sartin, 2013; Boulware, 2014). Field conditions here refer to those situations without organized, municipal or other piped water supplies. The present work focuses on those field conditions under which individual persons or groups produce their drinking water from various surface fresh water sources for direct consumption. This type of condition is usually encountered by military and aid personnel, hikers or any person in wilderness or emergency situations. Drinking water production, from surface water sources to the consumer, is described as a flow chart in Figure1 from the perspective of microbial safety and security. The term drinking water safety refers here to drinking water hygiene, microbiological hazards, microbial risk assessment and management of risks, whereas security refers to preventive measures for minimizing the risk that drinking water supplies will be tampered with or become targets for bioterrorism (Khan et al., 2011; Luthy, 2012; Rose, 2012). All these activities combined under the concepts of drinking water safety and security help ensure the microbial safety of drinking water. The term microbial pathogens refers here to the waterborne organisms, enteropathogenic bacteria, viruses and protozoa and the toxins produced by them and assessment of microbial safety regarding the possibility of these hazardous agents entering drinking water supplies (World Health Organization, 2013b).
