Chapter 1

INTRODUCTION

The quality of water resources is a subject of ongoing concern. The health and happiness
of the human race are closely tied up with the quality of the water used for consumption
where the per capita consumption of water is an index of quality of life of the people as
well as their economic and social condition. It is being estimated that, by the year 2025,
more than half of the world population will be facing water-based vulnerability
(Kulshreshtha, 1998).
Two major sources of drinking water are ground water and surface water.
Groundwater is the major source of water in our country with 85% of the population
dependent on it (Patel S. V. et al., 2007). The groundwater usually refers to the water
below the water table where saturated conditions exist. Under the influence of gravity
some infiltrating water slowly percolates through pores in rock such as sand stone. These
water bearing layers of the earth’s crust are called aquifers and the water in them is
known as ground water. There is no open space under the ground like river runs on the
surface except in cavernous limestone networks and some open lava tubes in volcanic
terrenes. The water travels by twisting through the pore spaces between the sand grains.
The smaller the pore spaces and the more difficult, fluids to pass through a solid are
known as permeability. The permeability depends largely on the amount of pore space
between the grains or crystals of the rock, the porosity. Thus the ground acts like a
sponge, seeking up rain in some places and leaking it out at other places.
The yearly amount of water flowing in streams in any region is directly related to
the annual rainfall. Most of the streams in arid or semiarid regions are dry except right
after the rare rains. On the average about 70% of the rainfall evaporates directly or
indirectly via plant transpiration of the remaining 30% travels through underground strata
along rivers and streams and about 90% of the total run off reaches the oceans. The
quantity of water remaining on the surface water after losses due to evaporation,
percolation and transpiration etc. is known as runoff and forms the surface for all surface
water. Rivers, lakes, ponds, streams, wetlands and oceans are all examples of surface
waters.

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1.1Background
Water is essential for sustaining life, and adequate, safe and accessible supply of water
must be available to all. Human and plant body consists of 60% and 90% water
respectively. Access to safe drinking water is essential to health, a basic human right and
a component of effective policy for health protection. Due to various ecological factors
either natural or anthropogenic, the groundwater is getting polluted because of deep
percolation from intensively cultivated fields, disposal of hazardous wastes, liquid and
solid wastes from industries, sewage disposal, and surface impoundments etc (Kass,
2005; Chofqi, 2004; Oren, 2004; Al Yaqout, 2003). Most of the biochemical reactions
that occur in the metabolism and growth of living cells involve water. The drinking water
risks in developing countries are mainly associated with microbial contamination with
about two dozen infectious diseases related to water quality. Millions of people all over
the world particularly in the developing countries are losing their lives every year from
water borne diseases (Arnal et al., 2001). Use of water containing viruses, bacteria and
protozoa, for drinking and cooking as well as contact with it and its intake during bathing
and washing, or even inhalation of small droplets in the form of aerosols may result in
spread up diseases like cholera, typhoid, bacillary dysentery, infectious hepatitis,
leptospirosis, giardiasis and gastroenteritis (Gadgil, 1998). Chemical contamination of
drinking water either naturally or by anthropogenic sources, is a matter of serious concern
as the toxic chemicals do not show acute health effects unless they enter into the body in
appreciable amounts, but they behave as cumulative poisons showing the adverse health
effects after a long period of exposure. The use of various structurally complex synthetic
compounds in the fields of industry and agriculture has added many potentially toxic
chemical substances in the aquatic environment. Of these, the important ones are arsenic,
barium, beryllium, cyanide, fluoride, lead, mercury, nickel, nitrate and nitrite, selenium,
silver etc. amongst the inorganic constituents and pesticides, polynuclear aromatic
hydrocarbons, phenols etc. amongst the organic constituents. There are other chemical
constituents, which are nontoxic, but affect the asthetic and organoleptic quality of water.
These include aluminium, chloride, colour, copper, hydrogen sulphide, iron, manganese,
dissolved oxygen, zinc, sulphate etc.
Therefore, the need to monitor drinking water quality has been universally
recognised and is a necessary safeguard against a large number of health hazards.

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1.2 Objectives
The present research has been formulated the following objectives for the study on the
quality of drinking water in the study area:-
1. To study the physical, chemical and microbial characteristics of the drinking water
in Dhemaji district, Assam.
2. To study the potability of water in the district.
3. To study the seasonal variations of different water quality parameters.
4. To study the correlations amongst the parameters and their significances.
5. To identify the most sensitive zones in the study area for different water quality
parameters with the help of GIS
6. To correlate the principal contaminants with the water borne ailments and health
hazards in the district.
7. To create a database on drinking water quality networking in the district

1.3 Importance of the study

Environmental disturbance is a crisis for the whole mankind. It is a problem for present
and future generation. It is necessary to bring awareness among the future generation
about causes and consequences of the problem. In the developing countries there is an
increasing awareness to protect the quality of water resources, as water is highly essential
for everyday life. In India there is increasingly greater evidence of the progressive
deterioration of water quality. The modern civilisation, industrialisation, urbanisation and
increase in population have led fast degradation of our water resources. Environmental
protection has become a major concern in developing countries in the last few decades.
This has accelerated the study of environmental pollution. Providing clean and safe
drinking water to all the people is still a far cry in many parts of India and as a result, this
has remained at the top of the government agenda for the last several years. Relative lack
of development, compounded with ignorance and hence unhygienic habits, poverty and
inadequate infrastructure facilities have made it an almost impossible task. The situation
is not better in Assam. The environmental monitoring is still in its infancy in Assam and
there is very little statistics on different environmental aspects related to this state. The
environmental screenings of water in Assam have been mostly restricted to Guwahati and
a few districts. Lack of properly trained persons, absence of equipments and other
infrastructuralfacilities and feeble public awareness have resulted in a very slow growth

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of the environmental sciences in Assam and the North Eastern region. The few studies,
undertaken so far, have revealed that the contamination levels of air, soil and water are
worrisome. Available literature shows that contamination of ground water has raised its
ugly head recently in Assam. The fluoride and arsenic contamination in ground water has
become a major public health issue in Assam. The contaminations of fluoride and arsenic
in groundwater of Assam have been confirmed by many studies carried out from time to
time. Arsenic has been detected in 21 of the 23 districts of Assam. The worst affected
areas are Nagaon, Karbi Anglong, Jorhat, Golaghat, Dhemaji and Lakhimpur district
(Singh A. K., 2004; Sushella A. K., 2007; Bhuyan et al., 2006; Nickson et al., 2007;
Chetia M. et al., 2008, Buragohain M. et. al., 2010; Saikia K. S. et al., 2009). These
alarming pictures of the water quality in the region and continuous consumption of this
water has potential of causing serious health hazard to the local population. No detailed
analysis of the water quality of the selected sources with respect to drinking water
contaminants had been undertaken before in the Dhemaji district of Assam to explore the
status of ground water quality. The present research has been undertaken with a specific
view to provide unfaltering records of drinking water contamination for safe future use so
that it is of value as an indicator of short-term improvement or deterioration in the
environment, when implementing remedial policies as well as to help users at national or
local level. In other words, the increasing recognition of the wide geographic spread of
the problem has provided the motivation to carry out this study at a regional scale.
For a rural and backward district like Dhemaji, where the majority of the people
live below the poverty line (BPL), the provision of safe drinking water is one of the prior
conditions for overall social development. Unfortunately, the basic facts in Dhemaji
district are that, the people are still unaware of drinking water contamination and their
probable effects. The governmental efforts are very poor than needed to mitigate the
crisis. Since water is directly related to human health, a health hazard survey among the
people of the study area is essential. This type of survey will definitely help to identify
the problem area and to create environmental awareness among the common people about
the causes and consequences of water pollution.
It is hoped that in bringing together and analyzing the past experience of all
researches, this study will contribute to the development of a more strategic and
operational response to the drinking water related issues so that concerted strategy can be
made at the planning level to keep the contamination of drinking water at the minimum.