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Description of key information

A toxicokinetic assessment was performed based on the available data of the substance. Based on the physical/chemical properties of the substance, absorption factors for this substance are derived to be 50% (oral), 100% (inhalation) and 50% (dermal) for risk assessment purposes. The bioaccumulation potential is expected to be high.

Key value for chemical safety assessment

Bioaccumulation potential:
high bioaccumulation potential
Absorption rate - oral (%):
50
Absorption rate - dermal (%):
50
Absorption rate - inhalation (%):
100

Additional information

A substance can enter the body via the lungs, the gastrointestinal tract, and the skin.

In general, a compound needs to be dissolved before it can be taken up from the gastro-intestinal tract after oral administration. Oxooil LS13 has a low water solubility (≤ 1.2mg/L), therefore it is not expected to dissolve into the gastrointestinal fluids, therefore uptake by passive diffusion is limited. Oxooil LS13 is a UVCB, the molecular weight of one of its main components (1-dodecene (and its isomers)) has an MW of 168.19. Based on the low molecular weight of its main component, Oxooil LS13 is favourable for absorption. Oxooil has a high log Pow (7.6-8.3), which makes the compound very hydrophobic. This characteristic will enable micellular solubilisation by bile salts in the gastro-intestinal tract which allows crossing of lipid biomembranes.

For risk assessment purposes oral absorption of Oxooil LS13 is set at 50%, based on its high log Pow, low water solubility and its low molecular weight. The results of the toxicity studies do not provide reasons to deviate from this proposed oral absorption factor.

Once absorbed, wide distribution of the test substance throughout the body is not expected based on its low water solubility. However, Oxooil LS13 has a low molecular weight which favours distribution. Overall, based on these data, distribution is expected to be limited.Excretion of Oxooil LS13 and its metabolites will occur via the bile (high molecular weight) or the urine (low molecular weight).Based on its high partition coefficient (7.6-8.3), it is likely that Oxooil LS13 will accumulate in adipose tissue.

The moderate vapour pressure (5 hPa at 20 °C) indicates that Oxooil LS13 can evaporate and reach the nasopharyncheal region or subsequently the tracheo/bronchial/pulmonary region via inhalation. If Oxooil LS13 reaches the tracheobronchial region, it is not likely to dissolve within the mucus lining the respiratory tract due to its low water solubility. However, if it dissolves into the mucus lining, based on its high log Pow, it is likely that micellular solubilisation will occur which will enable uptake of the substance by crossing of biomembranes.

Based on the above data, for risk assessment purposes the inhalation absorption of Oxooil LS13 is set at 100%.

When Oxooil LS13 comes in contact with the skin, the first layer of the skin, the stratum corneum, forms a barrier for hydrophilic compounds. Oxooil LS13 has a log Pow between 7.6-8.3, suggesting that the substance can be taken up in the stratum corneum. Since the substance is moderately volatile (5 hPa at 20 °C), penetration may be limited. Furthermore, due to its low water solubility (≤ 1.2mg/L), the transfer between the stratum corneum and the epidermis will be limited. According to the criteria given in the REACH Guidance, 10% dermal absorption will be considered in case MW >500 and log Pow <-1 or >4, otherwise 100% dermal absorption should be used. As the physical/chemical properties of Oxooil LS13 do not meet the criteria for limited dermal absorption (MW 168), for risk assessment purposes dermal absorption should be set at 100%. However, as it is generally accepted that dermal absorption does not exceed oral absorption, 50% dermal absorption of Oxooil LS13 is considered a realistic dermal absorption factor for risk assessment purposes.

Based on the high log Pow (7.6-8.3), the low water solubility (≤ 1.2mg/L) and the moderate vapour pressure (5 hPa at 20 °C), the dermal absorption for risk assessment purposes of Oxooil LS13 is set at 50%.The results of the toxicity studies do not provide reasons to deviate from this proposed dermal absorption factor.