Registration Dossier

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Hydrolysis:

Further testing is not required. Based on the data presented in this dossier, "Hydrocarbons, C14 -C20, aliphatics, < 2% aromatics" have been shown to be readily biodegradable. According to column 2 of Annex VII on the standard information requirements, hydrolysis studies do not need to be conducted if the substance is readily biodegradable.

Moreover, hydrolysis is not expected to be a signifcant mechanism of degradation in the environment because these substances lack hydrolitically reactive functionnal groups. Therefore, it is not subject to hydrolysis and this process will not contribute to the degradative loss from the environment.

Phototransformation in air:

Standard tests for atmospheric oxidation half-lives are intended for single substances and are not appropriate for this complex substance. However, this endpoint is characterized using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see library tab in PETRORISK spreadsheet attached to IUCLID section 13).

Phototransformation in water and soil:

The direct photolysis of an organic molecule occurs when it absorbs sufficient light energy to result in a structural transformation. The absorption of light in the ultra violet (UV)-visible range, 110-750 nm, can result in the electronic excitation of an organic molecule. The stratospheric ozone layer prevents UV light of less than 290 nm from reaching the earth's surface. Therefore, only light at wavelengths between 290 and 750 nm can result in photochemical transformations in the environment.

A conservative approach to estimating a photochemical degradation rate is to assume that degradation will occur in proportion to the amount of light wavelengths >290 nm absorbed by the molecule. This substance contains hydrocarbon molecules that absorb UV light below 290 nm, a range of UV light that does not reach the earth's surface. Therefore, this substance does not have the potential to undergo photolysis in water and soil, and this fate process will not contribute to a measurable degradative loss of this substance from the environment.

Biodegradation:

Based on the biodegradation results from relevant analogues ”Hydrocarbons C14 -C20, aliphatics (≤2% aromatics)”, showing biodegradation results above the trigger value, isoeicosane is also considered to be readily biodegradable and no further biodegradation studies are deemed necessary to conduct..

Bioaccumulation

Isoeicosane is a hydrocarbon UVCVB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is fulfilled using quantitative structure property relationships for representative hydrocarbon structures. The BCFBAF 3.01 model is a well characterised and generally accepted bioaccumulation prediction model, used by the USEPA, the OECD and recommended by ECHA. The SMILES input data for the BCFBAF 3.01 model is obtained from the PETRORISK Product Library (see OECD QSAR Toolbox report in 'Attached full study report' and PETRORISK report attached in IUCLID section 13).

The calculated BCF of isoeicosane ranges from 4.61 - 6.30 kg/L.

 

Adsorption / desorption:

Isoeicosane is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for this complex substance. However, this endpoint is characterised using quantitative structure property relationships for representative hydrocarbon structures that comprise the hydrocarbon blocks used to assess the environmental risk of this substance with the PETRORISK model (see Product Library in PETRORISK report attached in IUCLID section 13).

Adsorption coefficient has been calculated using Petrorisk. The log Koc for Isoeicosane ranges from 8.10 - 8.27.  The Koc for Isoeicosane ranges from 1.26 x10^8 - 1.86 x10^8.

Distribution modelling:

The distribution of the substance in the environmental compartments, air, water, soil, and sediment, has been calculated using the PETRORISK Model, version 5.3. Computer modeling is an accepted method for estimating the environmental distribution of chemicals. Distribution modeling results are included in the 'Multimedia distribution modeling results' tab in the PETRORISK spreadsheet attached to IUCLID section 13.

Based on the regional scale exposure assessment, the multimedia distribution of isoeicosane is 0.56 % to air, 0.02 % to water, 7.68 % to soil and 91.74 % to sediment. Distribution modeling results are included in the  'Multimedia distribution modeling results' tab in the PETRORISK spreadsheet attached to IUCLID section 13.