Agricultural pesticides and purification plants are the main sources of pollution in European rivers, which is greater than previously believed, according to a study on water quality by Swiss, German and French scientists.
In around half of the water analyses, the pollution presented an environmental risk. In 15% of cases, chemical substances risked having acute toxic effects on aquatic organisms.
The study, published in the latest edition of the United States scientific journal Proceedings, concludes that it will be difficult for European Union member states to reach their water quality targets for 2015.
The scientists, including some from the Swiss Federal Institute of Aquatic Science and Technology, analysed data on 223 chemicals taken from 4,000 measuring points in 91 rivers, including the Rhine and the Rhône.
Substances found in worrying quantities included ozone compounds, brominated flame retardants and polycyclic aromatic hydrocarbons, which result from the incineration process.
“In practice, that means something has to be done at all levels,” said study leader Ralf Schäfer, who called on agriculture to use fewer chemicals and for improvements to water purification plants.