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Administrative data

Link to relevant study record(s)

Description of key information

Low potential of bioaccumulation as log Kow <3.

Data related to metabolism of methylal (Dahl & Hadley, 1983; Tomilina et al., 1984; Poon et al., 2000; Virtue, 1951; Heilman J. & Duggan A., 2014), general metabolism of acetals (EFSA, 2011) and metabolism of degradation products (Ecetoc Publications, 2004) are provided in this section. Aim is to support the similarity of toxicokinetic behaviour between source and target of the read-across approach (Redebel, 2016).

Key value for chemical safety assessment

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

Additional information

ABSORPTION

Oral / gastrointestinal absorption

With a low molecular weight (160.26 g/mol), moderate water solubility (222.5 mg/L) and log Kow of 2.75, oral/gastrointestinal absorption of butylal is favoured subsequent to oral ingestion. Log Kow values between -1 and 4 are favourable for absorption by passive diffusion.

Oral absorption of butylal is set to 100% for risk assessment.

Inhalation absorption

Butylal low vapour pressure (0.079 kPa) indicates that the substance will unlikely be available for inhalation as a vapour. However, it will depend on the use. Its moderate log Kow value is favourable for absorption directly across the respiratory tract epithelium by passive diffusion. Solubility level of butylal in water indicates that it may be retained within the mucus.

Inhalation absorption of butylal is set to 100% for risk assessment.

Dermal absorption

As a liquid with a molecular weight close to 100 g/mol, butylal dermal uptake is favoured.

Based on molecular weight < 500 and log Kow in the (-1, 4) range, default dermal absorption of butylal is set to 100% for risk assessment.

Dermal absorption of butylal is set to 100% for risk assessment.

DISTRIBUTION

A wide distribution is expected due to the low molecular weight. As a small water-soluble molecule, butylal is going to diffuse through aqueous channels and pores.  

METABOLISM and EXCRETION

Butylalis not considered as substance with a potential to accumulate within the body. The read across report for the toxicity super endpoint showed a NOAEC > 2000 which indicates a very low risk of chronic toxicity.

The following values for absorption assessment were taken into account according to butylal behaviour (absorption, metabolism, distribution and elimination):

oral absorption of butylal is set to 100% for risk assessment;

inhalation absorption of butylal is set to 100% for risk assessment;

dermal absorption of butylal is set to 100% for risk assessment.