Plant protection products (PPP) can only be authorized if they have no unacceptable effects on the environment. Aim of the project was to investigate whether the ecology and behavior of soil organisms should be considered in PPP risk assessment. The possible spatial and temporal relationship between the preferred soil layer, the distribution of PPP and the ecotoxicological effects were studied in Terrestrial Model Ecosystems (TME). The results indicate that also soil organism living deeper in soils are affected by the concentrations detected in the uppermost soil centimeters. The implications for the development of terrestrial risk assessment guidance are discussed in the report.