World Health Organization (WHO) Recommendations on Water Quality Requirement

The control of water pollution is of utmost importance for developed and the developing countries. The control of water pollution by preventing it at the source, by the precautionary principles and the prior licensing of wastewater discharges by competent authorities have become key elements of successful policies for preventing, controlling and reducing inputs of hazardous substances, nutrients and other water pollutants from point sources into aquatic ecosystems. In a number of industrialized countries, as well as some countries in transition, it has become common practice to base limits for discharges of hazardous substances on the best available technology. In order to reduce inputs of phosphorus, nitrogen and pesticides from non-point sources (particularly agricultural sources) to water bodies, environmental and agricultural authorities in an increasing number of countries are stipulating the need to use best environmental practices6 . Approaches to water pollution control initially focused on the fixed emissions approach and the water quality criteria and objectives approach. Emphasis is now shifting to integrated approaches. The introduction of holistic concepts of water management, including the ecosystem approach, has led to the recognition that the use of water quality objectives, the setting of emission limits on the basis of best available technology and the use of best available practices are integral instruments of prevention, control and reduction of water pollution9-12. These approaches should be applied in an action-orientated way5 . A further development in environmental management is the integrated approach to air, soil, and food and water pollution control using multimedia assessments of human exposure pathways.