Abstract
A non-cancer inhalation chronic toxicity assessment for diethylamine (DEA, CAS number 109-89-7) was conducted by the Texas Commission on Environmental Quality. A chronic Reference Value (ReV) was determined based on a high-quality study conducted in mice and rats by the National Toxicology Program. Chronic inhalation ReVs are health-based exposure concentrations used in assessing health risks of long-term (i.e. lifetime) chemical exposure. DEA is used industrially as an organic intermediate to produce corrosion inhibitors, and is widely used in rubber, pharmaceuticals, resins, pesticides, insect repellants, dye processing and as a polymerization inhibitor. Although systemic effects have been noted at higher concentrations, DEA acts primarily as a respiratory irritant with effects occurring in the upper respiratory tract. Rats were exposed to 0, 31, 62.5 and 125 ppm DEA and mice to 0, 16, 31 and 62.5 ppm DEA for 6 h/day, 5 days/week for 105 weeks. Mice were slightly more sensitive than rats. The critical effect identified in mice was hyperostosis in the turbinates although DEA caused a number of other non-neoplatic lesions. Dose-response data were suitable to benchmark concentration (BMC) modeling. The human equivalent point of departure (PODHEC) was calculated from the 95% lower limit of the BMC(10) using default duration and animal-to-human dosimetric adjustments. Total uncertainty factors of 90 were applied to the PODHEC to account for variation in sensitivity within the human population, toxicodynamic differences between mice and humans, and database uncertainty. The chronic ReV for DEA is 11 ppb (33 µg/m(3)).