Ensuring clean drinking water

Providing adequate supplies of wholesome drinking-water which are free from any micro-organisms, parasites and substances which, owing to their numbers or concentration, constitute a potential danger to human health. This includes the protection of water resources which are used as sources of drinking water, treatment of water and the establishment, improvement and maintenance of collective systems.

Identifying the sources of waterborne pathogens and determining their impact on health, paying particular attention to the role of recently recognized pathogens, including protozoa and viruses. Developing quantitative methods for risk characterization for infectious agents. Establishing accurate estimates of the disease burden from low-level microbial contamination of drinking- and recreational water, leading to better control measures.

There are three types of water pollutant: microbiological, chemical and physical. Although chemical pollution is recognized as being of concern, exposure to microbiological agents poses the greatest threat to health. The risk of infection from waterborne pathogens, including protozoa and viruses, is likely to increase as polluted and/or limited groundwater resources lead to a shift towards extracting drinking-water from surface water, which is more vulnerable to contamination. Poor hygiene in regions suffering economic and political instability is exacerbating these microbial threats. Some microbes can be eliminated by boiling water before drinking it.

Each year, 3 million people throughout the world die as a direct result of drinking unsafe water. Even in the WHO European Region, there are 120 million people who do not currently enjoy an uninterrupted supply of microbiologically safe drinking-water. In Washington in 1996, city health officials advised people with weakened immune systems to boil their drinking water to eliminate bacteria.

This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities. Agenda 21 recommends improving, systematically sampling and evaluating drinking-water quality by introducing appropriate specific measures, including diagnosis of water-borne pathogens and pollutants.

Article 4(2)a of the Draft Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes, requires parties to take all appropriate measures for the purpose of ensuring: Adequate supplies of wholesome drinking water which is free from any micro-organisms, parasites and substances which, owing to their numbers or concentration, constitute a potential danger to human health. This shall include the protection of water resources which are used as sources of drinking water, treatment of water and the establishment, improvement and maintenance of collective systems.

Traditional methods of water coagulation, using natural water coagulants from the soil and plants are used in Peru and India.

Local authorities have the prime responsibility for eliminating this risk and dealing with instances of contamination, which, even when minimal, may result in catastrophic epidemics. It is up to them to do everything in their power to provide the population with a continuous supply of safe water. High-quality water can be guaranteed if certain simple rules are followed. One of these is disinfection of the resource by chlorine. This must continue to be a priority in every case, taking precedence over pre-treatment of water using highly specialized and often expensive techniques.