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Environmental fate & pathways

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A guideline-conform ready biodegradability study was being conducted. Menthyl acetate was not readily biodegradable in the study. A fraction of 48% was biodegraded at the end of the 28-day study period (clear indication that extensive primary biodegradation occurred) and biodegradation was still ongoing. Taking into account additional modelling with the BIOWIN program the substance can be considered as inherently biodegradable.

As menthyl acetate hydrolyses quite fast under environmental conditions (pH7) with a half-life of only 6 days, the substance can be regarded as rapidly degradable under environmental conditions. With a half-life time of < 16 days the criteria for rapid degradation according to the CLP/GHS criteria are as well fulfilled as the degradation products D,L-Menthol (CAS 89 -78 -1) and acetic acid (CAS 64-19-7) are not classified as hazardous to the aquatic environment. Furthermore, referring to ECHA PBT guidance document a "substance fulfils the P(vP) criterion if T1/2 > 40 (60) days". As it further can be shown that the two hydrolysis transformation products D,L-Menthol and acetic acid are not PBT/vPvB, according to ECHA PBT guidance document no further testing of degradation is required for the PBT/vPvB assessment. A persistence of menthyl acetate in the environment is therefore not expected.

The log Koc value was predicted with the program KOCWIN and with three QSPR methods. The log Koc = 3.196 indicates that the substance has low mobility in soil and sediment according to the classification scheme of McCall et al. (1981).

The Henry's Law constant that can be calculated from the available information on vapour pressure and water solubility shows that the substance is volatile from water surfaces under environmental conditions.

The BCF of the substance was calculated with the program BCFBAF using a fragment-based approach (Meylan et al. 1999) and with a QSAR built on the relationship between log Kow and BCF (Veith et al. 1979). The predicted values were 202 L/kg and 501 L/kg, respectively. The B criterion is not fulfilled for the substance menthyl acetate and the substance is considered as not bioaccumulative.