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Toxicological information

Neurotoxicity

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Description of key information

Delayed Neurotoxicity of Organophosphorus Substances Following Acute Exposure; Limit test (Protocol for acute delayed neurotoxicity studies: Section 163.81-7, U.S. Environmental Protection Agency's proposed guidelines [Federal Register 43 (163): 37362-37363, 1978]; similar to OECD 418): NOAEL (neurotoxicity): ≥ 11679 mg/kg bw/day (nominal); no neurotoxic potential.

Key value for chemical safety assessment

Effect on neurotoxicity: via oral route

Endpoint conclusion
Dose descriptor:
NOAEL
11 679 mg/kg bw/day

Additional information

In the key study, the acute delayed neurotoxicity of reaction mass of t-butylphenyldiphenyl phosphate and bis-t-butylphenylphenyl phosphate and triphenyl phosphate was investigated in an acute, oral, limit test (similar to OECD 418). 15 adult hens were treated with 11.7 g/kg Phosflex 51B, administered on day 1 and after three weeks. Hens were observed for six weekd. No treatment related effects were observed. It is therefore concluded that the test compound did not induce the neuropathologic alterations characteristic of delayed neurotoxicity in the hen. The NOAEL for neurotoxicity, based on adverse effects, neurobehaviour; neuropathology was 11679 mg/kg.

Two supporting studies, with no detailed test methods, were available for neurotoxicity. In both studies, no significant effects were observed, and it was concluded that t-BuTPP does not have neurotoxic potential.

Justification for classification or non-classification

Based on the available data, there is no evidence of neurotoxic effects for t-BuTTP. Therefore, based on the EU criteria outlined in 67/548/EEC and 1272/2008/EC t-BuTPP does not have to be classified with regard to neurotoxicity.