As a consequence of the increasing production of nanomaterials and subsequent release, there is increasing concern about their possible side effects in the environment. Due to their small size, nanoparticles (NPs) are more reactive than related non-nano materials and thus new biological effects may be expected. Metal NPs are being detected in the environment, and observations on uptake and adverse effects in organisms have already been described in the literature. Little data however, exist on the effects of NPs in soil.This study deals with the toxicity of metal NPs to soil-dwelling organisms with the aim of linking their fate and effects in terrestrial ecosystems. The work will be based on case studies with ZnO and Ag NPs, representing different fate kinetics.Toxicity tests will be performed to evaluate the effect of ZnO and Ag NPs on the earthworm Eisenia andrei and the nematode Caenorhabditis elegans, using different soil types (e.g. ranges of properties influencing metal binding capacity) and different ageing conditions. Measurement of toxicokinetics and exposure will help to unravel the main routes of uptake of metal NPs in these organisms. A full characterization of properties, fate and behaviour of metal NPs in soil will be essential to properly link exposure and effects.For that purpose, the training programme will put great emphasis on gaining and expanding knowledge on the fate of metal NPs in soil and uptake in organisms. This will require training in new techniques for detecting and characterizing metal NPs in different matrices, including soil, pore water and biological tissues. Metal speciation modelling will be learned to enable linking NP fate to bioavailability and toxic effects. Training will also include learning new ecotoxicological methods and modelling biological effects to address how NPs cause their effect on tissues. This training will be obtained through the host institution and its contacts.