Rare Earths Pollute Zurich's Waters

An investigation in the Swiss canton of Zurich has shown that certain rare earth elements can enter bodies of water via wastewater treatment plants in concentrations that pose a risk to aquatic organisms. These elements are gadolinium, which comes from contrast agents used in healthcare facilities, as well as lanthanum and cerium, which are used in a number of wastewater treatment plants to remove phosphorus.

Rare earth elements (see box) are omnipresent in our everyday lives, as they are an essential component of many modern technologies – for example in smartphones and LED lights, in electric motors and medical contrast agents. Besides the often problematic conditions under which rare earths are extracted, focus is increasingly turning to their release into the environment and the potential negative effects of their release. The aquatic research institute Eawag, together with the Ecotox Centre, has therefore carried out a study in the canton of Zurich over the last two years on behalf of the Canton of Zurich and the VSA Platform for Micropollutants Process Engineering. This study involved measuring the levels of rare earth elements in the effluents of 60 wastewater treatment plants and at 41 measuring points in watercourses and assessing the environmental risks. The results have just been published in the journal Aqua & Gas.

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