Drinking water quality analysis, Introduction

Chapter 1 :Introduction


Water is life. Water is essential for the survival of all forms of life and is used in various applications such as irrigation, domestic and sanitation purposes. Rivers are important sources to provide the daily needs of water both for animals and plants and are the most exploited in nature due to the changing lifestyle of the people, increasing urbanization and overpopulation. Without water, man’s existence on the earth would be threatened and he would be driven close to extinction. All biological organisms depend on water to carry out complex biochemical processes which aid in the sustenance of life on earth.


Over 70 per cent of the earth’s surface materials consists of water and apart from the air man breathes, water is one of the most important elements to man. Early civilizations flourished along the Nile, Tigris and Euphrates in ancient Mesopotamia, Indus in India, and Huang He in China due to their location near water sources (Ayoade, 1988:5) Though water covers about 70 percent of the earth’s surface, only 2.53 percent is fresh water while the remaining is salt water (UNESCO, 2003:8). The World Water Council also records that of the 3 percent of fresh water, only 0.3 percent is found in rivers and lakes, the rest being frozen (World Water Council, 2005). This suggests that man has a relatively low amount of fresh water resources with which he can carry out his activities.

Unfortunately, man’s influence has begun to degrade the fresh water resource available for his development. Pollution is the introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems, damage to structures or amenity, or interference with legitimate uses of the environment (Holdgate, 1979 cited in Alloway and Ayres, 1993).

According to UNESCO (2003), some 2 million tons of waste per day are disposed off within 2 receiving waters, including industrial wastes and chemicals, human waste and agricultural wastes such as fertilizers, pesticides and pesticide residues. Quality and quantity of freshwater sources worldwide are under pressures due to rapid population growth, inefficient agricultural practices, untreated discharges of domestic and industrial wastes, modification of river courses, atmospheric deposition, deforestation, climate change, and land use development. The quantity of water available for specific uses declines with massive pollution. When the quality of water deteriorates, it loses its economic values (Banerjee and Ghosh, 2012, Hoque et al., 2012).

Rivers are potential sources for freshwater and some flow through major cities and towns of the world. Urban areas provide the economic resources to install water supply and sanitation systems but they also concentrate waste. Where good waste management is

lacking, urban areas are among the world’s most life threatening environments (UNESCO, 2003). Some residential and industrial establishments are situated along waterways taking advantage of rapid urbanization and institutional failures and channeling waste into rivers causing River pollution. Rivers are natural resources which have ecological and recreational functions. People mostly depend on rivers for agricultural and domestic purposes. Many temples and crematories located around the river have increased cultural values of the rivers. But with rapid growing population and urbanization, different activities like unplanned building and encroachment, clearing of riparian vegetation along the river banks, disposal of waste materials in river and unwise mining of construction materials from the rivers are commonly observed in rivers. According to Dix (1981), ‘A river may be said to be polluted when the water in it is altered in composition or condition, directly or indirectly as a result of the activities of man, so that it is less suitable for all or any of the purposes for which it would be suitable in its natural state’. Where rivers flow through cities, they are likely to be polluted and this may have serious implications for health and socio economic wellbeing of persons who live in the immediate vicinity and those who use the water body downstream. Hardoy et al.,(2001), indicate that “River pollution from city based industries and untreated sewage can lead to serious health problems in settlements downstream” (Hardoy et al., 2001: 187).Some rivers lose their quality after they have passed through cities due to a number of human and industrial activities that contribute to their pollution. Settlements downstream that depend heavily on river water for domestic activities are forced to look for more expensive alternatives where such communities are not fitted with pipe borne water. Questions must be raised of the role of human and industrial activities as well as institutional and policy failures play in degrading the quality of a river as it flows through a city. The study sought answers to these questions in order to aid in formulating good policies and ensure the protection and sustainable use of our rivers and also contribute to understanding urban river pollution.

The Ratuwa river basin provides great benefits to Damak city and surrounding provinces. For e.g., the irrigation water for rice cultivation is primarily from the river. The river basin has been facing numerous challenges with deforestation, rapid urbanization, industrial growth and economic growth. The potential pollution sources are from several different sources, including landfills, domestic sites of domestic wastes, solid waste processing sites, outlets and confluences of canals, as well as deforestation. These driving forces may have impacts on the water quality scenario in this area. In addition, climate change will also impact the river basin, which will affect both human life and ecosystem services, including water quality. Therefore, an integrated water quality assessment of the Ratuwa river basin is needed in this area.

The contaminated river water is not a good sign for the human health and other aquatic organisms as it creates numerous health hazards. So, good quality of water is essential for all form of life and can be checked by examining its various physio-chemical and microbial parameters. Any alternation beyond the permissible range in these parameters makes the water polluted and may be unfit for any purpose for which it is intended to use. So, regular monitoring and analyzing of the water is essential to evaluate its quality and degree of pollution which is caused by anthropogenic activities or natural calamities. Damak is a small city in eastern Nepal where there is no practice for the management of river water. Dumping site of the municipality is also established at the bank of Ratuwa River from where the chances of mixing of contaminants are highly probable.

1.2 Water Quality parameters

The water pollution is assessed on the basis of certain parameters:

i. Physical, used to ascertain Temperature, turbidity, colour, conductivity, suspended,  dissolve and total solids.

ii. Chemical, used to ascertain inorganic matter such as acidity, alkalinity, salinity including several insoluble inorganic materials, soluble salts and organic matters.

iii. Microbiological, used to ascertain bacteria and pathogenic organisms.

1.2.1 Physico-chemical parameters

The ordinary consumer judges the water quality by its physical characteristics (Park, 2005). The chemical parameter is used to ascertain the presence of inorganic matter, soluble salts of organic matter in water. It can be argued that chemical standards for drinking water are of secondary consideration in a supply subject to severe bacterial contamination. The problems associated with chemical constituents of drinking water arise primarily from their ability to cause adverse health effects after prolonged periods of exposure; of particular concern are contaminants that have cumulative toxic properties, such as heavy metals, and substances that are carcinogenic (WHO, 1994).


Temperature is one of the important parameter of water and is bacically important for its effects on the chemistry and biological reactions in the organisms in the water. It is important in the determination of various parameters such as pH, conductivity, saturation level of gases and alkalinity etc. A rise in temperature of the water leads to the speeding of chemical reactions, enhanced growth of microorganism, reduction in solubility of gases and amplify tastes and odour (Trevedy and Goel, 1986). The temperature range of 7oC – 11oC has pleasant taste and more palatable than warm water (WHO, 1994).


pH is the measure of intensity of acidity or alkalinity (APHA, 1998). The pH value of drinking water from any sources should be within the range of 6.5- 8.5 (Trivedy and Goel, 1986). pH less than 7 may cause corrosion and encrustation in the distribution system where as the disinfection with chlorine is less effective is pH of water exceeds 8.0 (WHO, 1993). The pH of water affects treatment processes, coagulation and disinfection with chlorine-based chemicals. Change in the pH of source water should be investigated as it is a relatively stable parameter over the short term and any unusual change may reflect a major event (Payment et.al., 2003).

Electrical Conductivity

Conductivity is the measure of dissolved solids. Conductivity in water is affected by the presence of inorganic dissolved solids such as chloride, nitrate, sulfate and metal anion or cations (Trivedy and Goel, 1986). The contamination with wastewater also may increases the conductivity of the water so the abrupt change in the conductivity is the indicator of water pollution. Conductivity is strongly dependent on temperature and therefore is reported normally at 25oC.


TDS is the amount of solids that can pass through a glass-fibre filter. TDS is the remaining part that passes through the filter.TDS increases the conductivity and colour of water. High value of TDS in drinking water are generally not harmful to human beings but may affect persons who are victims of kidney and heart diseases. The total dissolved solids test is used as an indicator test to determine the general quality of the water. When TDS levels exceed 1000 mg\L, it is generally considered unfit for human consumption. High levels of TDS are caused by the presence of potassium, chlorides and sodium.


Dissolved oxygen refers to the level of free, non-compound oxygen present in water or other liquids. A dissolved oxygen level if too high or too low can harm aquatic life and affect water quality. DO enters water through the air or as a plant byproduct. Do is measured by using DO meter. A DO meter measures the amount of oxygen dissolved in an aqueous solution. Any healthy aquatic system which can support aerobic life must contain certain amount of oxygen; healthy bodies of water typically register at least 5 mg\l of DO. DO level less than 5mg\l can result in stressed aquatic organisms and level which remain as low as 1mg\l for even a few hours can result in widespread fish kills.

1.3 National Drinking Water Quality Standards 2062

The primary purpose of the Standards for Drinking-water Quality is the protection of public health. Safe drinking-water, as defined by the guidelines, does not represent any significant risk to health over a lifetime of consumption, including different sensitivities that may occur between life stages. The Guidelines describe reasonable minimum requirements of safe practice to protect the health of consumers and/or derive numerical “guideline values” for constituents of water or indicators of water quality. In order to define mandatory limits, it is preferable to consider the guidelines in the context of local or national environmental, social, economic and cultural conditions. The National Drinking Water Quality Standards (NDWQS)-2062 recently issued by Government of Nepal (GoN) are given in below Table 1.3.

Table 1.3: National Drinking Water Quality Standards-2062

S.N.ParameterUnitMax. Concn Limits
1.Temperature° C
3.Electrical conductivity (EC)μS/cm1500
5.Total Alkalinitymg/L
6.Free CO2mg/L


1.4 Objectives

A. Broad objectives:

The main objective of the research is to assess the water quality of Ratuwa river.

B. Specific objectives:

More specifically the research objectives are:

  • To find out the causes of the pollution of the Ratuwa river.
  • To identify the health effects resulting from the pollution of the Ratuwa River.
  • To measure the water quality parameters: physical (temperature, salinity, TDS), chemical (pH, DO), etc.


1.5 Research Questions:

  1. What are the causes of the pollution of the Ratuwa river?
  2. What are the health effects resulting from the pollution of the Ratuwa River?
  3. What are the possible measures to control pollution of the Ratuwa river?
  4. What are the management practices for conservation of the rivers?

1.6 Rationale of study

The water quality assessment study will be very important to assess the overall water resources management issues in the Ratuwa river basin. The water quality is a dynamic phenomenon. The proposed study will be a possible way of water quality monitoring activities for the development. This study can be able to establish some key issues of water quality that can be very useful.

Water resources have high value to present and future generation. Despite of all the benefits, increasing human pressure tends to degrade the water resources which increases pollution, increases negative impacts on health and becomes a great threat to human life. It is crucial to make people aware and involve them in its proper management.

The study aims to highlight the major cause of the pollution of the Ratuwa River so that pollution can be minimized. This study also focuses on the health impact caused due to pollution and makes people aware about this. By knowing the water quality of Ratuwa River after this study, it will be easy to set a suitable monitoring pathway for the regular checkup of water quality.

1.7 Limitation of the Study

The present study is limited to assessment of drinking water quality parameters of different sources in Damak municipality of Jhapa district, Eastern Nepal. The findings provide the water quality data for studied sources and areas only and cannot be generalized accurately the whole areas of Nepal. The sampling was carried out from February to July, 2019. Due to lack of time, adequate sample collection was difficult. All parameters stated in NDWQS-2062 were not analyzed due to applicability as well as lack of equipment and limited time. The study was conducted on winter season (February, 2019) and summer season (July, 2019). Due to time limitation the study could not carried out throughout the year.


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