A recent study shows for the first time that toxic chemicals pose ecological risks to European waters, as levels are much worse than previously thought.
European Union states, as required by the Water Framework Directive, had declared that they would make substantial water quality improvements by 2015. However, new research - conducted by the Institute for Environmental Sciences Landau together with the Helmholtz Centre for Environmental Research and fellow scientists from France and Switzerland - has shown that these goals are most likely unattainable. The reason: current water quality assessments don't account for the effects of toxic chemicals.
Up to now, environmental officials considered chemical pollution a local problem - one that affected only a few bodies of water. However, that is not the case. The study reveals that chemical toxins threaten almost half of all European bodies of water. And in approximately 15 percent of cases, the biota in freshwater systems may even be subject to acute mortality.
The international team, after investigating river thresholds in the river basin of major stream networks, found that some countries didn't recognize risks to their water quality because of inadequate chemical analyses or an incomplete list of possible toxic substances.
"Generally speaking we probably underestimated rather than overestimated the risks in our analyses," study leader Dr. Ralf B. Schäfer commented in a statement. "The actual state and condition of European freshwater ecosystems is probably even worse."
Runoff from agricultural activities, urban areas and municipal sewage treatment plants is the primary culprit. Pesticides, according to the study, were by far the most prevalent toxicants of freshwater systems. Also included were organotin compounds, brominated flame-retardants and combustion-derived polycyclic aromatic hydrocarbons.
European Union requirements currently focus on 40 specific chemicals known to be hazardous.
"Fortunately the use of many of these priority substances is no longer permitted and therefore, their concentration levels are steadily decreasing," added Dr. Werner Brack from the Helmholtz Centre for Environmental Research in Leipzig.
Still, toxic chemical levels are still uncomfortably high, so scientists behind the study urge industries to implement measures to prevent chemical dumping into water and improve sewage and wastewater treatment methods.