Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Phototransformation in air:

Substance is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for these complex substances. 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 Product Library in PETRORISK spreadsheet attached to Section 13 of the dossier).

Hydrolysis:

Hydrolysis is a reaction in which a water molecule or hydroxide ion substitutes for another atom or group of atoms present in a chemical resulting in a structural change of that chemical. Potentially hydrolyzable groups include alkyl halides, amides, carbamates, carboxylic acid esters and lactones, epoxides, phosphate esters, and sulfonic acid esters (Neely, 1985). The lack of a suitable leaving group renders compounds resistant to hydrolysis.

 

The chemical constituents that comprise hydrocarbons, C9, aromatics and hydrocarbons, C10, aromatics, >1% naphthalene consist entirely of carbon and hydrogen and do not contain hydrolyzable groups. As such, they have a very low potential to hydrolyze. Therefore, this degradative process will not contribute to their removal from the environment.

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 this fate process will not contribute to a measurable degradative loss of this substance from the environment.

Biodegradation:

Hydrocarbons, C9, aromatics, are inherently to readily biodegradable in aerobic freshwater systems with a biodegradation potential in the range of 56 to 78% following standard testing guidelines. These substances are not expected to persist in the environment under aerobic conditions.

 

Hydrocarbons, C10, aromatics, >1% naphthalene, biodegraded 58% after 28 days in an aerobic OECD 301F test, and under the conditions of the study was inherently biodegradable.

 

The above data is used for read across to Hydrocarbons, C9-C10, aromatics, >1% Naphthalene. However, Hydrocarbons, C9-C10, aromatics, >1% Naphthalene are hydrocarbon UVCBs. Standard tests for this endpoint are intended for single substances and are not appropriate for these complex substances. 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 Product Library in PETRORISK spreadsheet attached to IUCLID Section 13 of the dossier).

Adsorption / desorption:

Substance is a hydrocarbon UVCB. Standard tests for this endpoint are intended for single substances and are not appropriate for these complex substances. 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 Product Library in PETRORISK spreadsheet attached to Section 13 of the dossier).

Distribution Modelling:

The distribution ofHydrocarbons, C9 aromatics andHydrocarbons, C10, aromatics, >1% naphthalenein the environmental compartments, air, water, soil, and sediment, has been calculated using the PETRORISK Model, version 5.2.Distribution modelling results are included in the 'Multimedia distribution modelling results' tab in the PETRORISK spreadsheet attached to Section 13 of the dossier.

Based on the regional scale exposure assessment, the multimedia distribution ofHydrocarbons, C9 aromaticsis 92.9% to air, 3.5% to water, 1.9% to soil and 1.8% to sediment.

Based on the regional scale exposure assessment, the multimedia distribution ofHydrocarbons, C10, aromatics, >1% naphthaleneis 48% to air, 20% to water, 16% to soil and 16% to sediment.

This data is used for read across to Hydrocarbons, C9-C10, aromatics, >1% Naphthalene.