9-Octadecenoic acid (Z)-, sulfonated, potassium salts

Endpoint summary

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

10

Absorption rate - inhalation (%):

100

Additional information

There are no identified published data which could be identified on the toxicokinetics of the test substance. However, as per REACH guidance document R7. C, information on absorption, distribution, metabolism and excretion may be deducted from the physico-chemical properties including:

-       Water solubility

-       Partition coefficient

-       Vapour pressure

-       Molecular weight

The test substance is a UVCB, with all constituents having a molecular weight >500. It is a solid with a water solubility of 740 g/L at 20°C. Volatility was determined to be low (2.1 E-5 Pa at 20°C) and the substance has a limited lipophilic character (log Kow: <-4.89). Taking into account the log Kow and the water solubility, bioaccumulation of the test substance is considered to be unlikely.

Oral and gastrointestinal (GI) absorption: Given the water solubility and partition coefficient of the substance, it is likely to be partially soluble in GI fluid. Based on the high molecular weight of the majority of the constituents, they can then be expected to be partially absorbed through the GI system. However, in the absence of actual data, a default value of 50% has been considered for oral absorption.

Inhalation absorption: Given the log Kow of the major constituent, systemic uptake of the test substance after inhalation exposure could be expected, although this would occur only when aerosol or vapour is created under particular conditions (e.g. spraying, elevated temperature/pressure). In the absence of actual data,a default value of 100% has been considered for inhalation absorption.

Dermal absorption: Dermal absorption of the substance is expected to be limited. According to REACH guidance document R7.C, dermal absorption is maximal for substances with molecular weights below 500 and log Kow values ranging between 1 and 2. The substance has a molecular weight above 500 (>= 890.0 — <= 1030.0), which does not favour dermal absorption. Its water solubility is >10,000 mg/L (>740 g/L) and the log Pow is <0 (<-4.98), so that the substance may be too hydrophilic to cross the lipid rich environment of the stratum corneum. Also, there were no signs of systemic toxicity in the acute dermal toxicity study, the substance is not a skin irritant and not sensitizing. This suggests that dermal absorption may be low. Based on this evidence, a dermal absorption rate of 10% was selected, as per paragraph 1 of page 186 of the guidance.