This Research Front arose from the ‘9th International Conference on Environmental Effects of Nanoparticles and Nanomaterials’. This was a conference attended by nearly 150 people from 17 countries, at which the future environmental and health implications of ‘next generation’ nanoparticles was discussed—in particular, with a focus on nanohybrids, a key development in nanotechnology. The papers presented in this Research Front represent some of the best work on environmental nanoscience and the ecotoxicology of nanoparticles available.