Plastic is exceptionally durable, as it is only slowly degraded or transformed, and is transported over very long distances. Microplastics can therefore be found practically everywhere – in waters, in the soil and in the air. Due to its durability, plastic also accumulates in large quantities in the environment.
In 2014, the EPF Lausanne was commissioned by the Federal Office for the Environment (FOEN) to investigate microplastics in Swiss waters: Lake Geneva, Lake Constance, Lake Neuchatel, Lake Maggiore, Lake Brienz, Lake Zurich and the River Rhone. They found an average of 91,000 microplastic particles per km2 of lake surface. PE was most frequently represented, followed by PP and PS. The River Rhone transports an estimated 10 kg of microplastics to France every day. According to the FOEN, the concentrations found in Swiss waters pose no direct threat to the environment or water quality. However, their occurrence in waters is undesirable and relevant to the current ban on pollution under water protection legislation. The FOEN classifies the risk of microplastics getting into drinking water as low.
(Sources: “First Inventory of Microplastics in Swiss Waters”, FOEN, 2014; “Microplastics in the Environment”, Ökotoxzentrum, 2015)
In 2015 the Office for Waste, Water, Energy and Air (AWEL) examined the waters in the Canton of Zurich. According to the calculations of this study, 8 billion microplastic particles have accumulated in Lake Zurich, with a weight of 141 kg. Lake Greifensee and Lake Pfäffikersee have about 850 and 360 billion particles respectively, with a weight of 17 and 7 kg. In each case, the highest amount of microplastics is found on the surface of the waters. Both the Limmat and the Töss rivers have microplastic loads of 30 billion and 3 billion particles per day respectively. No microplastics have been detected in groundwater and drinking water.
(source: Scientific article “Microplastics in Wastewater and Waters”, Aqua&Gas No 7/8, 2016)