Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Hydrolysis and stability

L-Menthol has not been tested for hydrolysis under environmental conditions as it has shown to be readily biodegradable. The half-life of menthol in air has been assessed by using computational methods assuming pseudo-first order hydroxyl radical attack of menthol by hydroxyl radicals which resulted in an estimated half-life of 16 hours in air. Consequently, persistence of menthol in the atmospheric compartment is not expected.

Biodegradability

The biodegradability of L-menthol has been determined in a Closed Bottle test (OECD 301D). The test fulfilled the conditions of validity and shows that L-menthol can be regarded as readily biodegradable. 

Bioaccumulation

The bioaccumulation of DL-menthol in fish (Cyprinus carpio) was determined in a test according to standard method built by Japanese competent authority, and which is equivalent or similar to OECD guideline 305 C. Although the test substance in the report is DL-menthol, it can be considered as important information for L-menthol bioaccumulation potential. BCFs in the range of 0.5 - 15 L/kg with 0.2 mg menthol/L resp. 4.6 - 11 L/kg with 0.02 mg menthol/L were reported indicating no significant bioaccumulation potential. The variation of results may be partially explained by the variation of the lipid content in fish (2 - 6 %). As worst case, the BCF of L-menthol for fish was selected as 15.

The BCFfish (15) indicates that L-menthol has no bioaccumulation potential, and does not meet the criteria of “B” or “vB” under REACH.

Transport and Distribution

The distribution of menthols between aqueous solutions and air can be calculated from water solubility and vapour pressure. Thus a Henry’s law constants of 4.8 Pa.m3/mol (at 285 K) was obtained, indicating that menthol isomers are according to OECD 23 potentially volatile only under vigorous mixing conditions where the opportunity for water/air exchange is high.

The distribution between the organic phase of soil or sediment solids and water can be calculated from the octanol/water partitioning coefficient. Using EPISUITE as a calculation tool on the basis of log KOW 3.15 a KOC value of 149 L/kg was estimated, indicating a high mobility in soil and sediment (classification scheme according to McCall et al. (1981)) and a low sorption potential of the menthol isomers to soil organic matter.