Micropollutants (MPs) are organic or inorganic chemical pollutants which occur in water bodies in very low concentrations. Despite such low concentration levels, MPs can have negative impacts on organisms or contaminate the drinking water resources. MPs are derived from many products used in industry, agriculture, tourism and households and include personal care products, construction material, pharmaceuticals or biocides. They enter the water environment via various routes such as urban wastewater, or runoff from agricultural land or transportation areas.
Effects of micropollutants
Many MPscompounds are developed to be biologically active (e.g. biocides, pharmaceuticals, plant protection products). Therefore it is to be expected that similar but undesired side-effects can be observed in the environment. Herbicides for example that inhibit photosynthesis in weeds also stop photosynthetic activity in algae and macrophytes. Vertebrates, such as fish, will also react on e.g. hormones, or insecticides will also have a negative impact on insects in an aquatic environment.
Incomplete removal of MPs in conventional wastewater treatment plants
A major source for MPs in the aquatic environment are wastewater treatment plant (WWTPs) effluents. Conventional WWTPs have mainly been developed to remove nutrients. They successfully contributed to achieve water protection goals. Many MPs though are not sufficiently removed by conventional treatment processes. Therefore the Swiss authorities have decided to implement additional treatment steps on about 100 out of the 700 Swiss WWTPs. These modifications represent a unique opportunity to study the impact of MPs on natural aquatic ecosystems in our project EcoImpact.