A review of available sources identified acute oral toxicity data (LD50, LDLo) for various species (rat, mouse). Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected according to type of exposure, species, and route according to the hierarchies stated in Sections 3.3.1, 3.3.2, and evaluated using factors in Tables 3.2, 3.3, and 3.4. The most preferred source, a mouse oral LD50, was selected as the TEEL-3 basis. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• PAC-1 = TEEL-1 = TEEL-2/11
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Mouse oral LD50 (1800 mg/kg)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A and current TEEL-3 basis are both mouse oral LD50 toxicity data; however, the dose used in Rev. 29A was not found. Instead, a less conservative dose was selected as the TEEL-3 basis. The Rev. 29A TEEL-2 basis was a rat oral TDLo that could also not be found and was instead derived from the TEEL-3 (Table 3.5). The Rev. 29A and current TEEL-1 methodology remains consistent, with the difference in values due to the change of the TEEL-2 basis.