Water utilities warn: Ever-present chemical TFA could cause irreversible damage to drinking water.
The level of trifluoroacetate (TFA) in the Rhine has been rising for years. The problem is that the substance cannot be filtered out of the water.
The Lake Constance-Rhine Waterworks Association (AWBR) is becoming increasingly concerned about the chemical trifluoroacetate (TFA), which is being detected more and more frequently in the Rhine and other bodies of water. Drinking water is directly affected and could be irreversibly damaged, warned association presidents Matthias Maier and Roman Wiget at their general meeting.
TFA is a by-product of many chemical products, such as refrigerants, pharmaceuticals and pesticides, which cannot be filtered out of water using current methods. In the Upper Rhine alone, TFA concentrations have doubled in value over the last eight years, from 0.1 micrograms to 0.8 or 1 microgram per litre, Maier reports. And TFA discharges will continue to increase over the next 20 years,” he predicts.
The AWBR is an association of some 60 water utilities from Germany, Switzerland, Austria, the Principality of Liechtenstein and France. The member companies in the catchment areas of the Alpine lakes, Lake Constance, the Aare and the Rhine supply more than ten million people with drinking water every day.
Many pollutant exceedances
The association has monitoring networks on the Aare, Rhine, Danube and Neckar. With around 30 regularly sampled monitoring sites, it has the most extensive monitoring network on the Upper and Upper Rhine. As global warming means that it is no longer certain that the water in the four lakes will be completely recirculated, these bodies of water have also been included in the monitoring programme.
Each year, the AWBR produces a detailed annual report on its activities. It also includes a summary of the results of the monitoring programmes carried out by the working group.
Investigations focus on industrial chemicals, active pharmaceutical ingredients and pesticides. Organic micropollutants from these areas represent the largest group of substances. Many substances exceed the levels defined in the European River Memorandum (ERM).
Focus on TFA
TFA is of particular concern to the AWBR. The compound comes from a variety of sources, including refrigerants, pesticides and pharmaceuticals. The input is diffuse and the substance spreads everywhere. Removal by natural processes during drinking water treatment is currently not possible,” the report says.
In mid-2016, very high levels of this substance were detected in the Neckar River. The source was an industrial effluent. After production was relocated, the levels dropped significantly. However, the ERM target of one microgram per litre is still consistently exceeded.
In the Rhine, the levels at the two monitoring sites are even increasing and are already in the region of 75 per cent of the ERM target value of one microgram per litre. They are also increasing in the Alpine lakes, although they are still below the ERM target value.
TFA does not degrade, but any further input is found in the environment and in the water,” say Maier and Wiget. The AWBR is therefore calling for a ban on persistent chemicals wherever they are released into the environment. The quality of our drinking water depends directly on how we deal with substances like TFA.
Limits of treatment processes
The AWBR concludes its annual report by saying that recent years have shown that efforts to keep critical substances out of raw water and the Rhine must be intensified. A number of improvements have been achieved with regard to the discharge of problematic substances into the Rhine, for example by chemical companies reporting problems or installing modern wastewater treatment plants. The use of activated carbon filtration to treat groundwater after it has passed through soil has also made a big difference.
Further progress can only be achieved with more advanced purification stages. Two Swiss water utilities and AWBR members, IWB Industrielle Werke Basel and Hardwasser, have intensively discussed whether the existing multi-barrier system is sufficient for a safe drinking water supply or whether further measures are required.
It is true that treatment improves with more stages, but at the same time the environmental impact through the use of resources and energy increases. The adage ‘the devil goes with the devil’ applies here. For this reason, future measures would have to analyse the benefits/environmental impacts and weigh up the cost/benefit ratio.
