Chemical pollution of European waters is worse than anticipated
to inadequate sensitivity in chemical analysis or an incomplete list of ecotoxicologically relevant monitoring compounds.
“Generally speaking we probably underestimated rather than overestimated the risks in our analyses,” comments the head of the research study team, Jun.-Prof. Dr. Ralf B. Schäfer from the Institute for Environmental Sciences Landau. “The actual state and condition of European freshwater ecosystems is probably even worse.”
The release notes that the primary factors contributing to chemical contamination of aquatic ecosystems are the discharge from agricultural activities, urban areas and municipal sewage treatment plants. Pesticides were by far the major toxicants of freshwater systems, although, organotin compounds, brominated flame retardants and combustion-derived polycyclic aromatic hydrocarbons, also occurred at critical levels of concentration. EU requirements and targets regarding water quality currently focus primarily on the occurrence of the so-called priority substance, that is, around forty chemicals classified as being particularly hazardous to the aquatic environment. “Fortunately the use of many of these priority substances is no longer permitted and therefore, their concentration levels are steadily decreasing in many parts of the European streams. The real problem, however, is that a large number of chemicals which are currently in use are not taken into account at all in the context of water quality monitoring,” states Dr. Werner Brack from the Helmholtz Centre for Environmental Research in Leipzig. Additionally, recent findings show that for certain substances the assumed level(s) of effect concentration might be too high.
Improved definition of framework objectives and coordination are essential
In order to cope with the multitude of potentially hazardous substances, the scientists participating in this study recommend the introduction and intelligent linking of ecological and effects-based chemical screening methods as the only financially viable way of capturing the whole spectrum of ecotoxicologically relevant substances. “In this way,” Werner Brack points out, “hazardous substances can be detected even before they have been placed on the priority list.” The current study shows that there is an urgent need for action, especially with respect to the current chemical monitoring activities. “In practical terms, this means that urgent action is required at all levels, to ensure the sustainable protection of our aquatic ecosystems,” says Schäfer. The necessary steps to be taken range from general prevention of excessive chemical inputs into water bodies and the banishment and substitution of particularly problematic substances, up to a reduction in the application of agricultural chemicals and an improvement of sewage and wastewater treatment methods and technology. There is consensus among the members of the research team that, unless there is noticeable change to the current situation, the objectives and targets of the Water Framework Directive will not be met, due to toxicity from chemicals in the freshwater ecosystems. In the long term this may also lead to risks for humans, caused by possible failure of ecosystem services, such as impairment of the self-purification capacity of water bodies.
— Read more in Egina Malaja et al., “Organic chemicals jeopardize the health of freshwater ecosystems on the continental scale,” Proceedings of the National Academy of Sciences (15 May 2014) (doi: 10.1073/pnas.1321082111)
