A study requested by the European Commission into the problem of phosphorus pollution in lakes and rivers has recommended a ban on phosphate-based detergents and tougher implementation of the 1991 urban wastewater treatment Directive (UWWTD). These recommendations are based on the analysis of measures introduced in Member States and the rest of the world to address the rapid eutrophication of surface waters, and the environmental damage associated with it. Natural eutrophication is the process by which lakes and rivers gradually age and become more productive, essentially through the creation of algae, and takes place over thousands of years. Phosphates are a powerful stimulant of algal growth, and excessive levels of algae can lead to the disappearance of fish species and other forms of environmental pollution. The three main sources of manmade 'phosphorous load' in water systems are sodium tripolyphosphate (STTP) -based detergents, poorly treated water waste, and agricultural sources. Analysis of the methods by which some countries have been able to reverse the process of eutrophication has shown that a phosphorous reduction of 70 to 90 per cent is necessary to achieve this. This means that trying to tackle the sources of phosphorous load in isolation will have little effect on water quality. As a result, the study recommends methods to reduce all three forms of pollution in order to tackle the problem effectively. Specifically, it proposes: - A general ban on the use of STTP as a component of household detergents in all Member States; - Full implementation of the UWWTD; - Investigation of 'best management practices' for agriculture to reduce phosphorous loss to surface waters. In this way, it is hoped that we can begin to reverse the damage that has already been done to many of Europe's lakes and rivers.