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A cocktail of pollutants from medicinal products, pesticides and other chemicals pollutes the waters
Residues of medicines and pesticides are increasingly polluting the lakes and rivers. The Baden-Württemberg Ministry of the Environment has now for the first time submitted a report on the accumulation of so-called trace substances in the country's waters.
The report records the concentration of substances "which we do not want to have in our rivers and lakes and in our groundwater, even in the smallest quantities," said Baden-Württemberg State Minister for the Environment, Franz Untersteller (Bündnis 90 / Die Grünen). The “Trace substance report Baden-Württemberg 2012” shows, among other things, the contamination of the rivers and lakes with residues of medicinal products, pesticides and chemicals. The report is an "important situation analysis and a good basis for one of the most important permanent tasks of the country: the permanent improvement of the quality of our waters", the state environment minister continued.
Trace substances in waters with unknown effects on the environment The trace substances are usually only detectable in very low concentrations in the range of micro or nanograms per liter and are registered by human activities, reports the Baden-Württemberg Ministry of the Environment. Many of the substances do not yet know what effect they have on the human organism or on living things in rivers and lakes. For example, they come from drugs, X-ray contrast media, personal care products or cleaning agents. “Take medicines that are unfortunately disposed of in many households via the toilet flush. We will find these later as trace substances in the water, ”explains Franz Untersteller and added:“ Old pharmaceuticals belong in the residual waste - a simple but effective way of keeping water clean. ”
Pilot project on the concentration of trace substances in the Schussen According to the information from the State Ministry for the Environment, the trace substance report forms the basis for further water pollution control activities in Baden-Württemberg. In addition, Baden-Württemberg supports the “SchussenAktivPlus” project, which analyzes the occurrence of trace substances and the entry paths into the 62-kilometer inflow of Lake Constance. The investigations in the field of gunfire are part of a pilot project within the framework of the federal priority program "Risk management of new pollutants and pathogens in the water cycle". Under the direction of the biology professor Rita Triebskorn from the University of Tübingen, a team of 50 researchers has been working on the trace substances in the Schussen, one of the most polluted tributaries to Lake Constance, since the beginning of the year. The wastewater from several municipalities ends up in the river. The wastewater from sewage treatment plants is cleaned, but some trace substances remain unaffected.
Cocktail of 150 pollutants in the river The scientists discovered a mix of around 150 trace substances in the river, which apparently also has an impact on the creatures in the river. According to the study leader, trout with crippled ovaries and testicles can be found in the shooting area. In comparison to the animal in the much cleaner neighboring river, the Argen, the proportion is increased by 30 to 40 percent. Although the fish are apparently still able to reproduce sufficiently, the development is extremely questionable, according to the expert. Especially since the Schussen can also be rated as an "early warning system for Lake Constance". Regarding the origin of the pollutants, Prof. Rita Triebskorn explained that, on the one hand, these are residues of pesticides and fertilizers that get into the river when it rains. On the other hand, according to the expert, increased pollution comes primarily from wastewater.
Water pollution from pharmaceutical residues The wastewater contamination with drugs is a growing problem. Because people "are getting older and are taking more medication," the study leader explained. The substances contained then often end up in the wastewater with virtually no chemical change. When reprocessing in the wastewater treatment plant, nitrogen and phosphorus compounds can be reliably filtered out of the water, but other compounds can often not be eliminated in conventional plants. Accordingly, residues of the pharmaceuticals can still be detected in the water samples from the shot below the sewage treatment plants, explained Prof. Triebskorn. The concentration after the inflow from the sewage treatment plants is often significantly higher, since the trace substances only get into the river through the inadequately cleaned wastewater.
Modernization of wastewater treatment plant is funded The state government of Baden-Württemberg has also recognized the need for action with the wastewater treatment plants and is therefore supporting "among other things, municipalities that want to upgrade their wastewater treatment plants with an activated carbon filtration system, the so-called fourth cleaning stage", explained the state environment minister. Here, facilities that are located on surface waters that are used for drinking water supply, such as Lake Constance, would be preferred. The Langwiese wastewater treatment plant near Ravensburg is also to be modernized for around nine million euros. The installation of a further clarification stage with activated carbon filters is expected to be completed in May 2013. After that, the concentration of individual pollutants will be reduced by up to 90 percent, explained the technical manager of the Langwiese waste water association, Ralph-Michael Jung.
Drinking water supply over Lake Constance not affected? So far, the concentration of trace substances in the bowl has been questionable and even in the mouth of the river in Lake Constance, increased pollution levels can be demonstrated, but the drinking water supply from Lake Constance is not endangered, reports the Zweckverband Bodensee-Wasserversorgung. In the middle of the lake, it was therefore no longer possible to detect increased pollution due to the mixing with the water from the clean Alpine tributaries. "According to the current state of science, a risk to human health can be ruled out," the Zweckverband Bodensee-Wasserversorgung said in a recent announcement. However, the development must continue to be closely monitored, as around four million inhabitants of Baden-Württemberg obtain their drinking water from Lake Constance. It remains to be seen whether an improvement can be achieved by installing the activated carbon filter in the sewage treatment plant. (fp)
Picture: Photo: NABU / Helge May