Application of IATAs to DNT evaluation of organophosphorus flame retardants
Organophosphorus flame retardants are abundant and persistent in the environment due to their extensive use in industrial processes and products. The structural similarity of these flame retardants to organophosphate pesticides has prompted concern that they could potentially cause both acute neurotoxicity and developmental neurotoxicity (DNT).
DNT testing is traditionally done using animals, which is resource-intensive and fails to provide information on cellular processes affected by chemicals. OECD has published a series of case studies to support application of integrated approaches to testing and assessment (IATAs) to identification of potential developmental neurotoxicants. One of these case studies, developed by EPA and NIEHS scientists, used an in vitro testing battery to prioritize a class of organophosphorus flame retardants. The case study was published in September 2022.
Since the development of the IATAs, new data have become available that could refine the testing approach and provide a stronger case study. NIEHS is currently extracting these data and incorporating additional parameters such as exposure data, toxicokinetics, and endpoints and mechanisms relevant to DNT but not included in the original data. The revised dataset is described in an abstract (Oyetade et al.) accepted for a poster presentation at the 2024 annual meeting of the Society of Toxicology. The original case study submitted to OECD will be revised into a manuscript that will include and integrate the new data and updated resources into the information generated in the first project.