Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information

Since it is likely that the substance will be absorbed and in the absence of substance-specific absorption data, the default absorption values from the REACH guidance (Chapter 8, R.8.4.2) are used for DNEL derivation, namely: 100% for inhalation, 50% for oral and 50% for dermal absorption.

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

As no data are available on the toxicokinetics of the substance, relevant physical-chemical properties of the substance and data from toxicity studies indicating systemic bioavailability were considered to assess the general toxicokinetics of the substance.

Physical-chemical properties:

The substance is a yellow brown, viscous liquid with a molecular weight ranging from 520 -700 g/mol. The log Pow value lies between 1.72 and 2.20 and the solubility in water is 14.25 g/L.

Bioaccumulation:

Based on its log Pow value (below 3) the substance is unlikely to bioaccumulate with the repeated intermittent exposure patterns normally encountered in the workplace but may accumulate if exposures are continuous.

Gastrointestinal absorption:

Water-soluble substances may readily dissolve into the gastrointestinal fluids. Furthermore, the log Pow between 1.82 - 2.20 makes the substance favourable for absorption. However, the high molecular weight of the substance does not favour absorption. The mortality in the acute oral toxicity study (1 out of 6 rats dosed with 2000 mg/kg bw died) and the systemic adverse effects observed in the oral (gavage) repeated-dose toxicity study in rats (OECD422) indicate availability by the oral route. It is thus expected that the substance will be absorbed by the gastrointestinal tract.

Dermal absorption:

The log Pow between 1.82 - 2.20 and the high water solubility of the substance favour dermal absorption. On the other hand, the molecule may be too large for dermal uptake (molecular weight above 500). As the substance is a skin irritant, damage to the skin surface may enhance penetration. Further, the substance is a skin sensitizer and evidence of systemic toxicity (weight loss) occurred in the dermal studies with the substance (local lymph node assay in mice, acute dermal toxicity study in rats). Overall, these data suggest that the substance will be absorbed by the dermal route.

Respiratory absorption:

No experimental data is available concerning the respiratory hazard of the substance. The log Pow value between 1.72 - 2.20 is favourable for absorption directly across the respiratory tract epithelium by passive diffusion.As signs of systemic toxicity occurred in the oral toxicity studies with the substance, which indicates the potential for absorption following ingestion, it is likely that the substance will also be absorbed if it is inhaled.Overall, it is therefore expected that the substance will be absorbed by inhalation.

 

Since it is likely that the substance will be absorbed via the inhalation, oral and dermal route, and in the absence of substance-specific absorption data, the default absorption values from the REACH guidance (Chapter 8, R.8.4.2) are used for DNEL derivation, namely: 100% for inhalation, 50% for oral and 50% for dermal absorption.