Pollution in the Rhine
The Water Framework Directive has requested the member states of the European Union aim for a substantial improvement in freshwater quality by 2015. A recent study carried out by the Landau Institute of Environmental Sciences, the Helmholtz Center for Environmental Research (UFZ) and some French scientists (University of Lorraine and EDF) and Suizos (Swiss Federal Institute for Water Science and Technology Swiss - EAWAG), shows that this objective is far from being achieved, since the toxic levels in aqueous bodies remain extremely high.
The study shows, for the first time on a pan-European scale, that the ecological risks linked to toxic chemicals are considerably higher than expected. One of the main reasons is that in current measures to improve water quality the effects of certain substances are not taken into account.
Rivers like the Danube or the Rhine are fascinating ecosystems that provide services such as recreation, fishing and drinking water for millions of people. Unfortunately these ecosystems are exposed to the entry of chemicals from adjacent urban areas, from the farming and industry. This cocktail of chemicals negatively affects algae and freshwater animals and is a potential risk to humans.
Contrary to what has been thought until today (the affection by chemical toxins was very local and isolated), the study to which we refer reveals that taking into account the large-scale data, the ecological risk from toxic chemicals affects thousands of European aquatic systems. Chemical toxicity represents an ecological threat to at least half of the water bodies in Europe, and in approximately 15% of cases the biota in freshwater systems can be exposed to high mortality.
The group of researchers focused on studying the exceeding of risk limits for the basins of the Rhine and Danube estuaries, measuring them for the three most common groups of organisms in these waters, fish, invertebrates and algae. The data, obtained from official monitoring in recent years, indicates that the scope of the samples differs greatly in terms of spatial and temporal coverage, which makes direct comparison between different countries very difficult.
For example, it is indicated that the quality of water is worse in France, almost certainly due to the fact that the authorities in this country have an extensive control network and analyze a large number of substances, including ecotoxicologically relevant components , in many different water samples. In other countries, many of these risks may go unnoticed due to low sensitivity of the tests or because the list of controlled substances is incomplete. This, in general terms, makes the risks drawn from the analysis more likely to be underestimated rather than overestimated.
The main pollutants in aquatic ecosystems come from agricultural activities, urban areas, and municipal sewage treatment plants. Pesticides were by far the most commonly encountered pollutants in freshwater systems, although organo-tin compounds, organo-brominated compounds, and those derived from the combustion of hydrocarbons, also appear at critical concentration levels. In addition, a large number of chemicals used today are not taken into account when analyzing water quality and for certain substances, the permitted effective concentration levels may be too high.
The scientists participating in this study indicate that the only economically viable solution capable of covering the full spectrum of ecotoxicologically relevant substances would be the introduction of ecological methods and their intelligent combination with methods based on chemical filtration. In this way hazardous substances could be detected even before they were included in the toxic list. Another observation is that urgent action is needed at all levels if sustainable protection of aquatic ecosystems is to be ensured.
All members of the research group agree that if there is no radical change in the current way of proceeding, reaching the levels proposed by the Water Framework Directive will be impossible. The steps that should be followed if you really want to reduce input and eliminate toxic substances from aqueous systems would be, reducing the involvement of chemistry in agriculture and improving wastewater technology and treatments. If measures are not put in place, in the long term, they could pose direct risks to the human species, affecting the ecosystem and weakening the self-purifying capacities of the aquifers.
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Sources: Helmholtz Center for Environmental Research (UFZ), PNAS