Hydrocarbons, C10-C13, aromatics, <1% naphthalene

Endpoint summary

Description of key information

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 Aromatics C10-C15 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 air:

Standard tests for atmospheric oxidation half-lives 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 these substances with the PETRORISK model (see library tab in PETRORISK spreadsheet attached to 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.

Aromatics C10-C15 contain hydrocarbon molecules that absorb UV light below 290 nm, a range of UV light that does not reach the earth's surface. Therefore, these

substances do not have the potential to undergo photolysis in water and soil, and this fate process will not contribute to a measurable degradative loss of these substances

from the environment.

Biodegradation:

Hydrocarbons, C10-C13, aromatics, <1% naphthalene, biodegraded 70% after 28 days in an aerobic OECD 301F test, and under the conditions of the study and is readily

biodegradable.

Hydrocarbons, C10-C13, aromatics, >1% naphthalene, biodegraded 61% after 28 days in an aerobic OECD 301F test, and under the conditions of the study and is readily

biodegradable.

This data is read across to Hydrocarbons, C11-C15, aromatics, <1% naphthalene.

Adsorption / desorption:

Aromatics C10-C15 are 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).

Adsorption calculated for Hydrocarbons, C11 -C15, aromatics, <1% Naphthalene in PETRORISK is ca. 3.11.

Bioaccumulation

Standard bioaccumulation studies are not applicable to petroleum UVCB substances, therefore in accordance with Annex XI Section 1.3 testing is not scientifically necessary

and the endpoint has been fulfilled using QSAR calculations for relevant constituents based on BCFBAF v3.01.

BCF for Hydrocarbons, C11-C15, aromatics, <1% Naphthalene is 69.9 L/kg wet-wt.

Distribution:

The distribution of the substances in the environmental compartments, air, water, soil, and sediment, has been calculated using the PETRORISK Model, version 5.0.

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 Section 13 of the dossier.

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C10-C13, aromatics, >1% naphthalene is 91.9% to air, 1.6% to water, 3.2%

to sediment and 3.3% to soil.

 

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C10-C13, aromatics, <1% naphthalene is 93% to air, 1.4% to water, 2.6% to sediment and 3% to soil.

This data is read across to Hydrocarbons, C11-C15, aromatics, <1% naphthalene.