THE IMPACT OF CLIMATE CHANGE ON QUALITY OF DRINKING WATER IN MINNA, NIGER STATE
1.1 Background of Study
Water is a common natural chemical substance containing two atoms of Hydrogen and an atom of Oxygen. Its common usage refers to liquid form, though has other forms: solid water- ice and gaseous forms – water vapour and steam.
Water is indispensable for life and socioeconomic development of any society. It is used in domestic activities (cooking, drinking, washing, bathing etc), agricultural activities (e.g irrigation, gardening), generation of power (hydroelectric power plants), running industries, recreational activities etc. It is very essential for human existence and sustenance of life. Water constitutes 60%-70% of the total body weight. A man can live for several days without food but will only survive for few days without water. Therefore, water is indispensable for normal physiological function of plants and animals.1 In spite of its importance in sustenance of live and livelihood, it is the major cause of morbidity and mortality because of limitations in access and quality 2,3.
The basic physiological requirement for drinking water has been estimated at about 2 litres per capita per day which is just enough for survival 4,5 .World Health Organization (WHO) states that domestic water consumption of 30-35 liters per capita per day is the minimum requirement for maintaining good health 6. However, the amount of water required by individuals varies depending on climate, standard of living, habit of the people and even age and sex.
One factor that impinges more on the accessibility to enough quality drinking water is the distance of the source from house. This condition forces the individual most especially the women and children (especially girls) to transverse many kilometers to get safe drinking water (which deprives them from engaging in productive ventures or going to school like their male counterparts). In addition to this, in order to reduce the hardship in getting water, they may resort to reducing the quantity of water used in the house far below the recommended volume and also they may resort to fetching water from unimproved sources e.g. unprotected well, pond, stream etc7.
Safe (quality) drinking water is that which does not present any significant health risk over a life time consumption, including any sensitivities that may occur in different stages of life.8 It is water which is free from pathogenic microbes, hazardous chemicals/substance and aesthetically acceptable ( i.e. pleasing to sight, odourless and good taste). It is important that this type of water should not only be available, but also be available in enough quantity all the time 4 i.e. twenty-four hours a day, seven days a week (“24/7”). In assessing quality of drinking water, physical, chemical and bacteriological parameters must be considered. Although water from a source may not pose any health threat to consumers, they may abhor it due to its colour, odour, or taste 8. Physical parameters include colour, smell, temperature, PH, turbidity etc. There are myriad of chemical substances which may be naturally present or introduced (even chemicals used for water treatment) into water; those that are naturally present seldom pose risk to health. However, chemicals released due to anthropogenic activities (fertilizer, pesticides, herbicides, industrial effluents and byproducts etc) carry more health risk to consumers. Fortunately, whether chemical naturally present or introduced into water, there are maximum allowable concentration (limit) of most of them proposed by World Health Organization (WHO) which serves as guide. Some of the chemical substances include residual chlorine (RC), Iron (Fe), Fluoride (Fl), Nitrate/Nitrite, Lead (Pb), Mercury (Hg)8,9,10 etc.
Bacteriological (microbial) parameter is used to assess drinking water quality using the index /indicator concept as advocated by Waite (1991) 9. The infectious risks associated with drinking water are primarily those posed by faecal pollution and their control depends on being able to assess the risk from any water source and applying suitable treatment to eliminate the risk. Rather than trying to detect the presence of pathogens at which time the consumer is being exposed to possible infection, it is better practice to look for organisms, while not pathogenic themselves, that show the presence of faecal pollution and therefore the potential for the presence of pathogens. For this reason, Escherichia coli (E.coli) is universally used as an indicator organism to assess water treatment and widely preferred as index organism for faecal contamination.9 Thermotolerant coliform count (Faecal coliform) is acceptable where E.coli detection is not possible8,9.