Tall oil, compd. with ethanolamine

Endpoint summary

Description of key information

In accordance with Annex VIII of the Regulation (EC) 1907/2006 (REACH), an assessment of the toxicokinetic behaviour of the substance (as required in section 8.8.1) is performed to the extent that can be derived for the relevant available information. A toxicokinetic assessment was performed based on the available physical-chemical data and toxicological information available. Further testing for the assessment of toxicokinetic behaviour is omitted on this basis.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

25

Absorption rate - inhalation (%):

100

Additional information

In accordance with Annex VIII of the Regulation (EC) 1907/2006 (REACH), an assessment of the toxicokinetic behaviour of the substance (as required in section 8.8.1) is performed to the extent that can be derived for the relevant available information. A toxicokinetic assessment was performed based on the available physical-chemical data and toxicological information available. Further testing for the assessment of toxicokinetic behaviour is omitted on this basis.

Introduction

The substance is a brown paste and is a UVCB organic substance. No experimental studies of the absorption, metabolism, distribution or elimination of Tall oil, compound with ethanolamine (“the compound”) in mammals are available. However, information is available from existing toxicology studies on the compound, or for other very similar materials, and this data is used to infer, where possible, the potential toxicokinetic properties of the compound.

Physicochemical properties

Systemic availability of the compound depends on its ability to be absorbed across body surfaces. Factors that affect this process include water solubility, lipophilicity (measured by the partition coefficient, Kow), degree of ionisation (the dissociation constant, pKa) and molecular size. Given the large number of components within the compound, it has a molecular weight of 202 to 379 g/mol. It is considered insoluble in water (visually determined as < 1.18 mg/L in purified water at 20 °C). The dissociation constant was not technically feasible. The log Kow ranged from 4.10 to 7.75, with a weight average log10 Kow calculated to be 6.56.

Absorption

Oral absorption

The acute oral LD50 was found to be greater than 2000 mg/kg bw in an OECD 420 oral gavage study, with no clinical signs and no effect on body weight observed. In addition, no gross abnormalities were observed at necropsy. Nothing can be inferred about the nature of oral absorption from this study. In an OECD 422 repeat-dose/reproductive toxicity study, treatment with the compound at levels up to the limit dose of 1000 mg/kg/day was associated with marked toxicity, but limited systemic findings at the top dose suggest that some absorption took place. Because of the insolubility of the compound in water, and high Pow, complete absorption via the oral route is unlikely. In the absence of quantitative information, 50 % bioavailability following oral administration is assumed for the purposes of human risk assessment.

Dermal absorption

No acute dermal toxicity study is available. Skin irritation and sensitisation studies with very similar materials gave no signs that the test material reacted chemically with living layers of the skin or eye. Nothing can be inferred about the dermal penetration properties of the compound from these studies. For the purposes of risk assessment however, estimation of mammalian dermal absorption is made in accordance with principles adopted by the EFSA guidance on estimating dermal absorption of pesticide active substances (EFSA, 2012). On this basis, dermal absorption is estimated at 25 % for undiluted compound.

Inhalation absorption

In the absence of any quantitative data, absorption of the compound is considered to be 100 %.

Distribution, Metabolism and Elimination

No information is available to describe the distribution, metabolism or elimination of the compound, although repeat dose studies indicate at least exposure of the bone marrow.

Conclusion

For the purposes of human risk assessment oral absorption of the substance is estimated at 50 %, inhalation absorption is estimated at 100 % and dermal absorption is estimated at 25 %.