Portable Water

INTRODUCTION
Drinking water is one of the basic needs of life and essential for survival. Still more than one billion people allover the world do not have ready access to an adequate and safe water supply and more than 800 million of those unsaved live in rural areas. In India, ground water is being used as raw water for 85% public water supply. (According to world health report 1998) water supply varies widely interms of region and country. In 1970s, of the approximately 2.5 billion people in developing world, only 38% has safe drinking water. At the beginning of the 1980s, water supply coverage was 75% in urban areas and 46% in rural areas. In developing countries, 75% of the population had access to water supply. So they are always prone to loss of their lives or cost a big toll to save themselves from the occurrence of different water-borne disease. Water contamination due to pathogenic agents, chemicals, heavy metals, pesticides water disinfectants, and there by product as a consequence of industrial and agricultural activities leaching from soil, rocks, and atmospheric deposition and other human activities has become a hazard to human health in several regions of world.

Chemical aspects
The health concerns associated with chemical constituents of drinking-water differ from those associated with microbial contamination and arise primarily from the ability of chemical constituent to cause adverse health effects after prolonged periods of exposure. There are few chemical constituents of water that can lead to health problems resulting from a single exposure, except through massive accidental contamination of a drinking-water supply. Moreover, experience shows that in many, but not all, such incidents, the water becomes undrinkable owing to unacceptable taste, odour and appearance.
In situations where short-term exposure is not likely to lead to health impairment, it is often most effective to concentrate the available resources for remedial action on finding and eliminating the source of contamination, rather than on installing expensive drinking-water treatment for the removal of the chemical constituent.
There are many chemicals that may occur in drinking-water; however, only a few are of immediate health concern in any given circumstance. The priority given to both monitoring and remedial action for chemical contaminants in drinking-water should be managed to ensure that scarce resources are not unnecessarily directed towards those of little or no health concern (see the supporting document Chemical safety of drinking-water;.
There are few chemicals for which the contribution from drinking-water to overall intake is an important factor in preventing disease. One example is the effect of fluoride in drinking-water in protecting against dental caries. The Guidelines do not attempt to define minimum desirable concentrations for chemicals in drinking water.
The following methods are used for test water quality.
Dissolved oxygen
For dissolved oxygen “Winkler’s method with azide modification” is being followed (APHA,1998;part4500–OC,p.4-131).
Free carbon-dioxide
Free carbon-dioxide is being determined by NaOH titration method (APHA,1998;part4500-CO2,C,p.4-31).

Chlorides
For the determination of Chlorides “Argentometric method” is being applied (APHA,1998;part4500-ClB,p.4-67).
Nitrates
For the estimation of nitrates “Brucine method” is being used (TrivediandGoel,1984,p.59).
Phosphates
For the estimation of phosphates “Stannous chloride method ” is being applied (APHA,1998;part4500–PD,p.4-145).
Silicates
Determination of silicates is being done by “Molybdosilicate method” (APHA,1998;part4500-SiO2C,p.4-156).
Sulfates
Determination of sulphates is being done by “Turbidimetric method”(APHA,1998,part4500–SO42-E,p.4-178).
Total alkalinity
Total alkalinity of the sample is being determined by standard titrimetric method.
Phenolphthale in alkalinity and methyl orange alkalinity (APHA,1998,part2320B-CO2,D.,p.2-27).
Total hardness and calcium hardness
These are being determined by EDTA titrimetric method”(APHA,1998,part2340,C,p.2-36)

2. Radio-active (Radiological) aspects
   The health risks associated with the presence of naturally occurring radionuclides in drinking-water should also be taken into consideration, although the contribution of drinking-water to total exposure to radionuclides is very small under normal circumstances.
   Formal guideline values are not set for individual radionuclides in drinking water.
   Rather, the approach used is based on screening drinking-water for gross alpha and gross beta radiation activity. Although finding levels of activity above screening values does not indicate any immediate risk to health, it should trigger further investigation to determine the radionuclides responsible and the possible risks, taking local circumstances into account.
   The guidance levels for radionuclides recommended in these Guidelines do not
   apply to drinking-water supplies contaminated during emergencies arising from accidental releases of radioactive substances to the environment.
3. Physical Aspect: taste, odour and appearance

Water should be free of tastes and odours that would be objectionable to the majority of consumers.
In assessing the quality of drinking-water, consumers rely principally upon their
senses. Microbial, chemical and physical constituents of water may affect the appearance, odour or taste of the water, and the consumer will evaluate the quality and acceptability of the water on the basis of these criteria. Although these constituents may have no direct health effects, water that is highly turbid, is highly coloured or has an objectionable taste or odour may be regarded by consumers as unsafe and rejected.
In extreme cases, consumers may avoid aesthetically unacceptable but otherwise safe drinking-water in favour of more pleasant but potentially unsafe sources. It is therefore wise to be aware of consumer perceptions and to take into account both health related guideline values and aesthetic criteria when assessing drinking-water supplies and developing regulations and standards.
Changes in the normal appearance, taste or odour of a drinking-water supply
may signal changes in the quality of the raw water source or deficiencies in the treatment process and should be investigated.
Roles and responsibilities in drinking-water safety management
Preventive management is the preferred approach to ensuring drinking-water safety
and should take account of the characteristics of the drinking-water supply from
catchment and source to its use by consumers. As many aspects of drinking-water
quality management are often outside the direct responsibility of the water supplier, it is essential that a collaborative multiagency approach be adopted to ensure that agencies with responsibility for specific areas within the water cycle are involved in the management of water quality. One example is where catchments and source waters are beyond the drinking-water supplier’s jurisdiction. Consultation with other authorities will generally be necessary for other elements of drinking-water quality management, such as monitoring and reporting requirements, emergency response plans and communication strategies.
Major stakeholders that could affect or be affected by decisions or activities of
the drinking-water supplier should be encouraged to coordinate their planning and
management activities where appropriate. These could include, for example, health
and resource management agencies, consumers, industry and plumbers. Appropriate mechanisms and documentation should be established for stakeholder commitment and involvement.
Surveillance and quality control
In order to protect public health, a dual-role approach, differentiating the roles and
responsibilities of service providers from those of an authority responsible for independent oversight protective of public health (“drinking-water supply surveillance”), has proven to be effective.
Organizational arrangements for the maintenance and improvement of drinking water supply services should therefore take into account the vital and complementary roles of the agency responsible for surveillance and of the water supplier. The two functions of surveillance and quality control are best performed by separate and independent entities because of the conflict of interest that arises when the two are combined. In this:
National agencies provide a framework of targets, standards and legislation to enable and require suppliers to meet defined obligations;
Agencies involved in supplying water for consumption by any means should be required to ensure and verify that the systems they administer are capable of delivering safe water and that they routinely achieve this;
A surveillance agency is responsible for independent (external) surveillance through periodic audit of all aspects of safety and/or verification testing.
In practice, there may not always be a clear division of responsibilities between
the surveillance and drinking-water supply agencies. In some cases, the range of professional, governmental, nongovernmental and private institutions may be wider and more complex than that discussed above. Whatever the existing framework, it is important that clear strategies and structures be developed for implementing water safety plans, quality control and surveillance, collating and summarizing data, reporting and disseminating the findings and taking remedial action. Clear lines of accountability and communication are essential.
Surveillance is an investigative activity undertaken to identify and evaluate
potential health risks associated with drinking water.
Surveillance contributes to the protection of public health by promoting improvement of the quality, quantity, accessibility, coverage (i.e. populations
with reliable access), affordability and continuity of drinking-water supplies (termed “service indicators”). The surveillance authority must have the authority to determine whether a water supplier is fulfilling its obligations.
In most countries, the agency responsible for the surveillance of drinking-water
supply services is the ministry of health (or public health) and its regional or departmental offices. In some countries, it may be an environmental protection agency; in others, the environmental health departments of local government may have some responsibility.
Surveillance requires a systematic programme of surveys, which may include
auditing, analysis, sanitary inspection and institutional and community aspects. It
should cover the whole of the drinking-water system, including sources and activities in the catchment, transmission infrastructure, treatment plants, storage reservoirs and distribution systems (whether piped or unpiped).

4. Microbial (Biological aspect) water quality
   For microbial water quality, verification is likely to be based on the analysis of faecal indicator microorganisms, with the organism of choice being Escherichia coli or, alternatively, thermotolerant coliforms. Monitoring of specific pathogens may be included on very limited occasions to verify that an outbreak was waterborne or that a WSP has been effective. Escherichia coli provides conclusive evidence of recent faecal pollution and should not be present in drinking water.
   Under certain circumstances, additional indicators, such as bacteriophages or
   bacterial spores, may be used.
   However, water quality can vary rapidly, and all systems are at risk of occasional
   failure.
   For example, rainfall can greatly increase the levels of microbial contamination in source waters, and waterborne outbreaks often occur following rainfall. Results of
   analytical testing must be interpreted taking this into account.

REFERENCES
APHA, AWWA, WEF (2005) Standard methods for the examination of water and wastewater,
21st ed. Washington, DC, American Public Health Association, American Water Works
Association and Water Environment Federation, pp. 7–15.
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