Water Quality Standards for Drinking Water
Access to safe drinking water is essential for public health protection. Since 1994, the World Health Organization (WHO) has been setting standards and guidelines for the quality of drinking water. The purpose of the WHO standards is to provide the highest possible level of protection againstemergent risks, including those posed by chemicals, biological agents and radionuclides found in drinking water.
The first of these Guidelines was the Guidelines for Drinking-Water Quality (GDWQ) issued in 1993 andwhich established risk-based standards for communities in developing countries, thereby meeting the need fordrinking water to be safe for human consumption. The GDWQ was the first comprehensive and detailed quantitative guideline ever published and addressed chemical, physical and microbiological parameters.
In 1994, the WHO Water Quality Programme published the first issue of the WHO Recommended Drinking-Water Quality Guidelines which provides guidance on the quality of volatile organic compounds, nonvolatile organic compounds, metals and nutrients, as well as on the bacteriological quality of drinking-water.
The most recent edition, WHO Drinking-Water Quality Guidelines, Third Edition (CJ 94-1999) was published in 1999. It was revised to ensure that the same standards were applied uniformly throughout the world and to update the list of contaminants including some new compounds such as benzene, formaldehyde and phenols.
The CJ 94-1999 Drinking-Water Quality Guidelines consists of two parts: the primary standards and secondary standards. The primary standards cover all chemical, physical and microbiological contaminants, while thesecondary standards are based on aesthetic criteria such as taste, odour, colour, and turbidity. The Guidelines specify maximum allowable concentrations for specific toxins in drinking water, as well as procedures for monitoring, assessment and control of these pollutants, and realistic goals for public awareness, education and outreach.
To achieve the WHO standards, countries should establish an acceptable maximum level of each chemical, physical or microbiological contaminant in drinking water and should monitor compliance with them. This can be done through regular monitoring and assessment of water quality. Monitoring and assessment are needed in order to identify any episodes of pollution and to determine if the drinking water is suitable for human consumption.
The WHO also recommends that countries develop an effective system for the management of water resources, which should include a monitoring program, contingency plans, and preventive measures. Furthermore, the safe management of drinking water sources should include information sharing, participation of local communities, and effective enforcement of standards.
To conclude, the WHO standards provide the baseline for drinking water safety in all developing countries, while still allowing a degree of flexibility in how the standards are implemented. Several countries have adopted their own drinking water quality guidelines, which are more stringent than the WHOs primary and secondary standards, in order to ensure the protection of public health. It is essential that countries embrace the WHO standards and develop effective strategies for water resource management in order to protect public health.
