Tall oil, potassium salt

Endpoint summary

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100

Additional information

A toxicokinetic assessment was performed based on the available physico-chemical data and available toxicological information.

 

Introduction

The substance is a UVCB organic substance. No experimental studies on the absorption, metabolism, distribution, or elimination of Tall oil, potassium salt 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 substance 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) and molecular size. Given the large number of components within the compound, and excluding the potassium, it has a molecular weight of ca. 250-350 g/mol. It is considered soluble in water (visually determined as 93.8 g/L in purified water at 20 ºC). The log Kow ranged from 5.64 to 7.22, with a weight average log10 Kow calculated to be 6.4 (measured at 40 ºC).

 

Absorption

Oral absorption

The acute oral LD50 of the read across compound (crude tall oil, EC no. 931-433-1) was greater than 2000 mg/kg bw. In addition, no gross abnormalities were observed at necropsy. In a OECD 422 repeat-dose/reproductive toxicity screening study with distilled tall oil (EC 232 -304 -6), effects on liver function were seen at high doses (500 mg/kg bw/day). This finding suggests that oral absorption of distilled tall oil takes place up to some extent. In the absence of quantitative information, 50% bioavailability following oral administration is assumed for the purposes of human risk assessment.

 

Dermal absorption

Acute dermal toxicity studies were conducted with the read-across substance crude tall oil, but no adverse effects were observed in this study. Skin irritation and skin sensitisation studies with crude tall oil produced no signs that the test substance reacted chemically with the skin. According to the ECHA guidance, substances with MW less than 100 are expected to cross this skin barrier fairly easily. For substances with MW greater than 500 are difficult to get absorbed. For the purposes of risk assessment however, 50% bioavailability is assumed following dermal absorption.

 

Inhalation absorption

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