Ranking initial environmental and human health risk resulting from environmentally relevant nanomaterials

As nanomaterials find increased application in common and industrial products and processes so too the potential for release of these novel materials into the environment increases. The characteristics of these materials also may result in novel toxicological actions related to their nanoscale, which will have implications on their ecotoxicological and toxicological limits of exposure and eventual regulation. A framework for nanomaterials risk assessment on regulatory, ecotoxicological and toxicological bases developed from recent exposure and toxicity studies is presented. The release of nanoscale TiO2, Ag and CeO2 to the atmosphere and surface waters is assessed against provisional toxicological bench mark doses (BMDs) and critical effect doses (CEDs) developed from best available data. Predicted levels of nanomaterial release to surface waters and the atmosphere resulted in regulatory risk rankings of moderate concern based on worst case provisional regulatory limits. Inhalation and ingestion risk rankings were of very low concern based on the provisional inhalation and ingestion toxicity BMDLs and CEDLs detected for the nanomaterials in question. More toxicological data is required on nanoscale CeO2 inhalation to develop a true dose response as in vitro cytotoxicity studies yielded an inhalation risk ranking of lower concern. The moderate to high ecotoxicological risk rankings posed by the release of nanoscale TiO2 and Ag to surface waters highlights the need for guidance and restriction on the usage and disposal of com. products containing nanomaterial. The risk rankings presented in this assessment give a first indication of the relative risks posed by the usage and release of these materials into the environment and indicate what materials require further investigation into their nano-specific toxicological actions. As more nanorelevant toxicity studies are published, end-points and risk levels related to nano-specific toxicity actions may be detected and the provisional BMDLs developed as part of this framework refined, resulting in more confident risk rankings.

Authors: O’Brien, Niall; Cummins, Enda ;Full Source: Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances & Environmental Engineering 2010, 45(8), 992-1007 (Eng) ;