Colloids and nanoparticles constitute a large part of the total reactive surface area of the planet. Their role in environmental processes is only partially understood. Frank develops specific experimental and analytical methods to elucidate the transformation, interaction and general behaviour of colloidal/nanoscale particles in the environment. His group uses the acquired knowledge and sophisticated analytical techniques to better understand environmental nanoscale processes. He supports the risk assessment of nanomaterials by improving our understanding of incidental and manufactured nanoparticles in the environment. This includes development of methods for identification and quantification of nanomaterials in food, cosmetics and the environment, as well as the development of regulatory tools on OECD and ISO levels.