Drinking water quality standards and regulations

Water is the most essential component for human life. Supply of safe drinking-water is a basic human right that not only protects human health, but also contributes to social development and to the reduction of expenses related to health care. The main aim of establishing this guideline is to assist ensuring the safety of drinking water supplies through the elimination or reduction of problematic constituents that may cause adverse health effects. In this regard, heavy metals are considered to cause particular concern because of of their cumulative toxic characteristics even at low concentration. In general, the purpose of water treatment is to protect the consumer from pathogens, toxic materials and other impurities in the water that may be injurious to human health. Treatment processes can be classified into physical, chemical, and biological processes. Physical treatment processes cause change in contaminants levels through the application of physical forces. In chemical treatment the removal of contaminants is caused by the addition of chemicals or by chemical reaction. In biological treatment the removal of contaminants is caused by biological means such as bacterial degradation. Various treatment processes can be applied, solely or in series, to accomplish gradual and complete removal (in a logical economical manner) of all impurities that pose potential health treats. Water parameters (not all which are considered contaminants) can be divided into four classes: Physical parameters (such as turbidity, color, taste and odor), some times refer to as indicator parameters or organoleptic parameters; Chemical parameters (such as most ions including heavy metals, pesticides and other organic substances); Biological parameters (such as bacteria viruses, protozoa and others) and Radiological parameters (including natural and man-made radionuclides). Detailed quantitative standards or recommendations for the various classes of water parameters are given either by national legislation or guidelines, or by global organization such as the World Heald Organization (WHO, 2004, 2006, 2008).