The objective of this work was to provide focused toxicity information for constituents of IMX-101 including 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN) that will allow for more accurate benchmark derivation consistent with existing regulatory guidance and frameworks and allow for optimal operational flexibility at ranges while ensuring environmental health. Through acquisition of needed toxicity data in this work and through the publication of these data in the scientific peer-reviewed literature, information obtained from this work will be provided to regulatory agencies to derive health-based criteria, enable wastewater permit actions, determine degree of personal protective equipment when exposed, and enable range managers to protect the environment while sustaining range operations.

Toxicity tests were conducted with NTO in mammals, birds, and an amphibian species; studies conducted with DNAN were done using conventional aquatic species. Study results were also published in the peer-reviewed literature and provisional environmental criteria were developed to protect human and environmental health.

Acute and chronic DNAN aquatic toxicity data suggest that DNAN is slightly less toxic than other nitroaromatics such as TNT. Studies conducted using frog embryos (Lithobates pipiens) suggest low toxicity of NTO when buffered. Extended generation reproductive studies conducted in rats showed results suggestive of male reproductive effects (hypospermia), but no evidence of developmental effects or changes to number of offspring born. Acute effects in birds were marked by neurotoxic signs such as ataxia supported by adverse brain histology (cerebellar vacuoles); no reproductive effects were observed at lower exposures.

Together, these data will allow development of toxicity-based benchmarks and science-based environmental criteria for environmental releases such as waste water discharge allowances, and clean-up criteria.  Based on these and other data, media-based concentrations were developed for soil and drinking water.

Emily May Lent, Lee C. B. Crouse, Allison M. Jackovitz, Erica E. Carroll& Mark S. Johnson (2016): An extended one-generation reproductive toxicity test of 1,2,4-Triazol-5-one (NTO) in rats, Journal of Toxicology and Environmental Health, Part A, DOI: 10.1080/15287394.2016.1219893