Trioctylphosphine oxide

Endpoint summary

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

50

Additional information

The toxicokinetic assessment is based on the available physico-chemical properties and toxicological data of the substance. According to REACH Guidance R.7C, the molecular weight lower than 500 g/mol of Tri-N-octylphosphine oxide is favourable for absorption in the gastrointestinal tract. A very low water solubility (estimated at 0.74 µg/L) and a high log Pow (estimated at 9.54) may limit uptake, although micellar solubilisation may play a facilitating role. Acute oral and dermal toxicities are low; it is not possible to conclude on whether this is due to low intrinsic toxicity of the substance or low uptake. In the absence of additional data, an oral absorption of 100% is assumed for risk assessment purposes.

Based on its physical form (waxy solid) and low vapour pressure (0.004 Pa at 50°C),exposure via inhalation will not be significant under ambient conditions.

According to the criteria given in the REACH Guidance, 10% dermal absorption will be considered in the case of a molecular weight > 500 g/mol and a log Kow < -1 or > 4, otherwise 50% dermal absorption should be proposed. Given the physico-chemical characteristics of the substance, a dermal absorption of 50% was therefore considered for risk assessment purposes.

Given the presently available data, no additional conclusions can be drawn on the distribution, metabolism and excretion of Tri-N-octylphosphine oxide after dermal and inhalation absorption.