A review of available sources identified the following acute mouse and rat toxicity studies (LDLo) for several routes. In addition, analysts evaluated the mercury IDLH (Hg, CASRN: 7439-97-6). 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. Analysts compared TEELs from acute toxicity against the IDLH; from this, it was determined that the IDLH was overly conservative for this chemical and its bases not comparable to diphenyl mercury. Instead, analysts selected the most preferred species and route, a rat oral LDLo, as the TEEL-3 basis. TEEL-1 and -2 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LDLo (500 mg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was molecular weight adjusted exposure limits for mercury compounds (IDLH, Hg, excluding [organo] alkyls; CASRN: 7439-97-6) and TLV-TWAs for (organo) alkyl compounds. Analyst assessed this chemical is not an alkyl compounds; instead, the TEEL-3 basis was a rat oral LDLo for diphenyl mercury, from which TEEL-2 and TEEL-1 values were derived (Table 3.5).