He has been working for more than 20 years on the ecotoxicology of chemicals and nano in terrestrial ecosystems, with emphasis on linking effects from the molecular level to the community level. He is an expert in risk assessment of chemicals and nano, advisor on test guidelines, guidance document and risk assessment for various national EPAs, Nordic Council, EU and OECD. Co-Leader of the US-EU Risk CoR. He is an experienced project leader national and international nano-related projects. He is continuously supervising Post Doc and phD students. He publishes continuously.