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Description of key information

Key value for chemical safety assessment

Additional information

No study is available in which the toxicokinetic properties (distribution, metabolism, elimination) of the substance were specifically investigated. In fact, such a study is hardly feasible due to the complex UVCB-composition of the substance.

The expected toxicokinetic behaviour is derived from the physicochemical properties, the results from the available toxicological studies and the available literature following the information given in guidance document 7c.

 

The substance is a solid (at 20°C) with a water solubility of <0.05 mg/L (20°C) and a lipophilic character (log Pow >5.7). It has a very low vapour pressure of <0.014 P (20°C) and consequently a very low volatility. It is not surface active.

 

Oral and GI absorption:

Substance is not soluble in water and in GI fluids. It will not easily pass through aqueous pores or epithelial barriers. The substance or parts of the substance may be taken up by micellular solubilisation. The limited systemic toxicity data on representative constituents of the substance furthermore does not indicate absorption through the GI tract. This is supported by experimentally determined poor gastrointestinal absorption of the main constituent octadecan-1-ol.

 

Inhalative absorption:

The substance does not easily pass through aqueous pores or epithelial barriers. Absorption via the lung is therefore not assumed to occur to a significant extent.

 

Dermal absorption:

Due to the physico-chemical information, the substance can be assumed to be absorbed via the skin. 

 

Distribution:

Because of the very low solubility, poor distribution can be assumed. Fatty alcohols may enter lipid biosynthesis, but fatty acids derived from fatty alcohols will be indistinguishable from the lipids derived from other sources.

 

Accumulative potential:

Based on the PC information the main site of accumulation is assumed to be the adipose tissue as well as skin. No accumulation in bone or in lung is predicted. There is only limited potential for retention or bioaccumulation for long chain alcohols, i.e. the parent alcohols and their biotransformation products.

 

Metabolism:

Linear or essentially linear hydrocarbon chains are readily oxidised metabolically. Long chained alcohols, which sum up to about 70%of the substance, are generally highly efficiently metabolised either by oxidation to the corresponding carboxylic acids, followed by a stepwise elimination of C2 units in the mitochondrial β-oxidation process. The end product acetyl CoA enters the citric cycle and is furthermore metabolised to CO2 and water. This process may be preceeded by a ω or ω-1 oxidation. Alternatively, they might be used in lipid biosynthesis. Consequently, there is limited potential for retention or bioaccumulation for the parent alcohols and their biotransformation products.

The wax ester components of the substance are assumed to be metabolised to alcohols and fatty acids, both of which are further metabolised as described above.

 

Reactivity:Available studies on genotoxicity were negative, i.e. there is no indication of a reactivity of the test substance or its metabolites under the test conditions.

 

Excretion:

The metabolic end products carbon dioxide and water are excreted via urine or exhaled.