We test and assess the environmental compatibility of plant protection products in accordance with national and international plant protection legislation (in particular EC 1107/2009). To this end, we develop and implement tailored studies for higher tier risk assessment (HTRA), e.g. life cycle tests with fish, species sensitivity distributions (SSDs) and mesocosm studies including chemical analyses. The experimental work is complemented by statistics, exposure and effect modelling. As a consequence of our experience with in house studies for pesticide manufacturers and our work for and in co-operation with authorities, we can often mediate between notifiers and authorities when it comes to the evaluation of studies or the determination of an optimal test strategy.