Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Substance characterisation

The test substance Orange oil is an NCS composed of a range of constituents: hydrocarbon terpenes (typically 83%) and 13% of non hydrocarbon terpenes consisting of 7% monoterpenoids (oxyfunctionalized monoterpenes: citral, a-terpineol, citronellal, and linalool), and 6% non-branched aldehydes (octanal, decanal). In the typical orange oil, the main constituent d-limonene is present at 80%. The composition with d-limonene and some minor constituents that are structurally related to limonene, represents a relatively homogenous type of NCS and the environmental risk assessment may be based on the properties of the main constituent d-limonene. The minor constituents have different properties for water solubility, volatility, adsorption and lipophility that determine their environmental behaviour. Due to these differences the assessment of the environmental properties of orange oil is preferably based on data for the constituents.

 

Based on the constituent approach as described in the industry protocol for the REACH registration of NCSs of botanical origin used as fragrance ingredients (see footnote 1), Orange oil is to be considered as a readily biodegradable substance. The water solubility ranges from 3.5 to 1770 mg/l for the constituents.

The log Kow of the constituents is above 4.0 for 83% and above 4.5 for 6% of the typical constituent composition whereas for only one constituent (3%) the log Kow is below 3. With log Kow 4.38, d-limonene represents the group with a high log Kow (Koc of limonene estimated at 2413). Thus most constituents will have a tendency to sorb to organic matter.

The BCF of the constituents in Orange oil was calculated to be in the range of 32 – 156 for monoterpenoids, typically 13% of Orange oil, and 261 – 395 for hydrocarbon terpenes, typically 83% of orange oil. As the constituents are readily biodegradable, it is likely that they will also be biotransformed in higher organisms so a high bioaccumulation factor is actually not expected.

The estimated vapour pressure of orange oil was 181 Pa, ranging from 2.6 to 536 Pa for the constituents. For d-limonene (typically 80%) the vapour pressure is 193 Pa and 6% of the constituents composition has a higher vapour pressure. This indicates that partitioning by volatilisation may play a role.

 

Classification and PBT assessment

Although Orange oil is considered readily biodegradable, the log Kow is >4 for typically 83% of the constituents. As there is no tested BCF for Orange oil or for its main constituent d-limonene at the moment, a classification for long-term effects in the environment is applied as a worst case for both the classification according to Regulation 1272/2008/EC (CLP).

Based on its ready biodegradability, Orange oil does not fulfill the criteria for Persistent. As typically 94% of the components has a log Kow <4.5, Orange oil is also not considered bioaccumulative.

 

(1) A statement on the use of the protocol for Registration of Natural Complex Substance (NCS) under REACH has been attached to the dossier.

Additional information