A review of available sources did not identify exposure limits or acute toxicity data for potassium orthovanadate. There is available acute toxicity data (LD50, LDLo) for a similar metal salt, sodium orthovanadate (CASRN: 13721-39-6) that were evaluated. In addition, there are available exposure limits for vanadium (V as V₂O₅; CASRN: 1314-62-1; IDLH, PEL-C, REL-C, TWAs) and vanadium pentoxide (CASRN: 1314-62-1, LOC). 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 vanadium IDLH was considered as a TEEL-3, however analysts selected the most preferred route and species toxicity data available for sodium orthovanadate as the TEEL-3 basis, a rat oral LD50, given that this data corresponds to the actual toxicity of similar salt. A molecular weight adjustment was applied (Section 3.4.3.2) to this TEEL-3. The LOC was considered as a TEEL-2; however, this value was not selected because 1) it is derived from the IDLH, which was not selected as a TEEL-3, and 2) it is an order of magnitude greater than other TEEL-2 available bases (ceiling limits, TWAs; Section 3.3.1). Instead, the most preferred vanadium ceiling limit, the PEL-C, was selected as the TEEL-2 and a compound adjustment factor was applied (Section 3.2.2). The TEEL-1 value was derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = MW-adjusted PEL-C (vanadium dust, as V₂O₅, CASRN: 1314-62-1, 0.5 mg/m³)
• TEEL-3 = MW-adjusted rat oral LD50 (sodium orthovanadate, CASRN: 13721-39-6, 330 mg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 was a molecular weight adjusted vanadium IDLH, while the current basis is a molecular weight adjusted rat oral LD50 for sodium orthovanadate (CASRN: 13721-39-6). The Rev.29A TEEL-2 was a molecular weight adjusted REL-C, while the current TEEL-2 is a molecular weight adjusted PEL-C, a more preferred source (Table 3.1). The Rev. 29A and current TEEL-1 use the same methodology (Table 3.5), with differences due to the change in TEEL-2.