Fatty acids, tall-oil, polymers with glycidyl neodecanoate

Endpoint summary

Description of key information

There were no studies available in which the toxicokinetic properties of test substance were investigated. However, as per REACH guidance document R7. C (2014), information on absorption, distribution, metabolism and excretion may be deduced from the physico-chemical properties. Based on the physico-chemical properties and the available toxicological data, the test substance is expected to have moderate to low absorption potential via the oral, dermal and inhalation routes. The log Pow of the substance ranges from 2.4 to 5.1, which suggests that bioaccumulation of some of the constituents could occur. However, given the use as an intermediate, exposure will be very low, so that the overall extent of bioaccumulation will also be low.

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

Oral absorption

According to REACH guidance document R7.C (May 2014), oral absorption is maximal for substances with molecular weight below 500. Water-soluble substances will readily dissolve into the gastrointestinal fluids; however, absorption of hydrophilic substances via passive diffusion may be limited by the rate at which the substance partitions out of the gastrointestinal fluid. Further, absorption by passive diffusion is higher at moderate log Kow values (between -1 and 4). If signs of systemic toxicity are seen after oral administration (other than those indicative of discomfort or lack of palatability of the test substance), then absorption has occurred.

The test substance is a UVCB with a molecular weight range of 268-800. The two main constituents, present at>35 - <45% (w/w), have molecular weights of 508 and 510, respectively. The substance is a liquidwith low water solubility (15.6 mg/L) and a log Pow ranging from 2.4 to 5.1. Vapour pressure was determined to be low (0.004 Paat 20°C). No significant treatment-related effects were seen in acute oral toxicity testing up to 2000 mg/kg bw.

Based on the R7.C indicative criteria, oral uptake is assessed to be moderate to low. A default value of 50% will be used for DNEL derivation purposes. 

 

Dermal absorption

According to REACH guidance document R7.C (May 2014), dermal absorption is maximal for substances with molecular weight below 500 and log Kow values ranging between 1 and 2. The major constituents of test substance have molecular weights above 500 and the log Pow range is 2.4 to 5.1. This suggests that the substance may not penetrate very easily through skin.

Therefore, an oral equivalent default value of 50% dermal absorption has been applied for DNEL derivation.

 

Inhalation absorption

According to REACH guidance document R7.C (May 2014), inhalation absorption is maximal for substances with VP >25 KPa, particle size (<100 μm), low water solubility and moderate log Pow values (between -1 and 4). Very hydrophilic substances may be retained within the mucus and not be available for absorption.

The test substance, because of its relatively low vapour pressure of 0.004 Pa at 20°C, will not be available as vapours for inhalation underambient temperature working conditions.As the substance is an intermediate, it will not be available for inhalation as vapours or as aerosols. Further, if there were to be inhalation exposure, considering its physico-chemical properties (log Kow, water solubility and MW ), no significant solubilisation in mucus is expected. Hence, the substance will most likely reach the lower respiratory tract after which the absorption fate of the deposited material will be similar to the oral route/gastrointestinal tract.

Overall, based on all the available weight of evidence, the test substance is expected to have low to moderate absorption through the inhalation route. Nevertheless, a conservative default value of 100% has been considered for DNEL derivation.

 

Bioaccumulation potential

The log Pow of the substance ranges from 2.4 to 5.1, which suggests that bioaccumulation of some of the constituents could occur. However, given the use as an intermediate, exposure will be very low, so that the overall extent of bioaccumulation will also be low.