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Phototransformation in air

The phototransformation in air was estimated from the AOPWIN v1.92 calculations of phototransformation.

 

The phototransformation rate of decane is 11.11 x 10-12 cm3/molecule/sec. The calculated half-life is 0.963 d (11.552 hrs). This value is largely below the trigger limit (2 days). Therefore, decane is not persistent.

 

The phototransformation rate of undecane is 12.52 x 10-12 cm3/molecule/sec. The calculated half-life is 0.854 d (10.249 hrs). This value is largely below the trigger limit (2 days). Therefore, undecane is not persistent.

 

The phototransformation rate for dodecane is 13.94 x 10-12 cm3/molecule/sec. The calculated half-life is 0.767 d (9.210 hrs). This value is largely below the trigger limit (2 days). Therefore, dodecane is not persistent.

 

The phototransformation rate of tetradecane is 16.76 x 10-12 cm3/molecule/sec. The calculated half-life is 0.638 d (7.657 hrs). This value is largely below the trigger limit (2 days). Therefore, tetradecane is not persistent.

 

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. The lack of a suitable leaving group renders compounds resistant to hydrolysis

 

The chemical constituents that comprise Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, < 2% aromatics 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

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. Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, < 2% aromatics 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.

 

Phototransformation in 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. Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, < 2% aromatics 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 in water: screening tests

Hydrocarbons, C9-C11, n-alkanes, isoalkanes, cyclics, <2% aromatics, biodegraded 80% after 28 days under the conditions of the study and is readily biodegradable.

 

Hydrocarbons, C9-C11, cyclics, <2% aromatics biodegraded to an extent of 53% after 28 days. The data support characterizing Hydrocarbons, C9-C11, cyclics, <2% aromatics as exhibiting moderate rate of biodegradation (inherently biodegradable).

 

A persistence (P) screening assessment has been realized for decane using EPI suite BIOWIN 2, 3 and 6 (v4.10) models, in accordance with Reach Guidance R.11. The Biowin 2 probability being 0.9908 > 0.5, and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months (value 3.4814 > 2.2), the criteria indicating that the substance does not biodegrade fast are not fulfilled. The Biowin 6 probability being 0.8691 > 0.5 and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months, the criteria indicating that the substance does not biodegrade fast are not fulfilled. So, the biodegradation prediction by BIOWIN does not lead to the conclusion that Decane would be persistent.

 

A persistence (P) screening assessment has been realized for undecane using EPI suite BIOWIN 2, 3 and 6 (v4.10) models, in accordance with Reach Guidance R.11. The Biowin 2 probability being 0.9888 > 0.5, and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months (value 3.4504 > 2.2), the criteria indicating that the substance does not biodegrade fast are not fulfilled. The Biowin 6 probability being 0.8718 > 0.5 and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months, the criteria indicating that the substance does not biodegrade fast are not fulfilled. So, the biodegradation prediction by BIOWIN does not lead to the conclusion that Undecane would be persistent.

 

Hydrocarbons, C10-C12, isoalkanes, <2% aromatics biodegraded to an extent of 31% after 28 days and 41% after 41 days during a non-acclimated phase of the test. Hydrocarbons, C10-C12, isoalkanes, <2% aromatics biodegraded to an extent of 42% after 28 days and 48% after 41 days during an acclimated phase of the test.

 

Hydrocarbons, C10-C12, isoalkanes, cyclics, <2% aromatics biodegraded to an extent of 7.34% after 24 days and 8.74% after 31 days. Hydrocarbons, C10-C12, isoalkanes, cyclics, <2% aromatics is not inherently biodegradable.

 

Hydrocarbons, C10-C13, isoalkanes, cyclics, <2% aromatics, biodegraded 89.8% after 28 days under the conditions of the study and is readily biodegradable.

 

Hydrocarbons, C10-C14, isoalkanes, cyclics, <2% aromatics biodegraded to an extent of 16.07% after 24 days and 18.39% after 31 days. Hydrocarbons, C10-C14, isoalkanes, cyclics, <2% aromatics is not inherently biodegradable.

 

Hydrocarbons, C11-C12, n-alkanes, <2% aromatics biodegraded to an extent of approximately 77% after 28 days. The data support characterizing Hydrocarbons, C11-C12, n-alkanes, <2% aromatics as rapidly biodegradable (readily biodegradable).

 

Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, a multi-component substance, biodegraded to an extent of 69% after 28 days. The data support characterizing Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics as rapidly biodegradable, readily biodegradable, not expected to persist in the environment under aerobic conditions. Although it did not meet the 10-day window requirement, it is characterized as readily biodegradable because the criterium is not applied to multi-component substances when assessing their ready biodegradability.

 

A persistence (P) screening assessment has been realized for dodecane using EPI suite BIOWIN 2, 3 and 6 (v4.10) models, in accordance with Reach Guidance R.11. The Biowin 2 probability being 0.9863 > 0.5, and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months (value 3.4194 > 2.2), the criteria indicating that the substance does not biodegrade fast are not fulfilled. The Biowin 6 probability being 0.8746 > 0.5 and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months, the criteria indicating that the substance does not biodegrade fast are not fulfilled. So, the biodegradation prediction by BIOWIN does not lead to the conclusion that Dodecane would be persistent.

 

Hydrocarbons, C12-C13, isoalkanes, cyclics, <2% aromatics biodegraded to an extent of 12.69% after 24 days and 13.69% after 31 days. Hydrocarbons, C12-C13, isoalkanes, cyclics, <2% aromatics is not inherently biodegradable.

Hydrocarbons, C12-C16, isoalkanes, cyclics, <2% aromatics biodegraded to an extent of 22% after 28 days and 50% after 70 days. Hydrocarbons, C12-C16, isoalkanes, cyclics, <2% aromatics is not readily biodegradable, but can be considered inherently biodegradable.

 

Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, <2% aromatics, a multi-component substance, biodegraded to an extent of 68% after 28 days and 69% after 31 days. The data support characterizing Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, <2% aromatics as rapidly biodegradable, readily biodegradable, not expected to persist in the environment under aerobic conditions. Although it did not meet the 10-day window requirement, it is characterized as readily biodegradable because the criterium is not applied to multi-component substances when assessing their ready biodegradability.

 

Tridecane biodegraded to an extent of 83% after 28 days and 86% after 32 days. The data support characterizing tridecane as rapidly biodegradable (readily biodegradable).

Hydrocarbons, C13-C14, n-alkanes, <2% aromatics biodegraded to an extent of approximately 79% after 28 days. The data support characterizing Hydrocarbons, C13-C14, n-alkanes, <2% aromatics as rapidly biodegradable (readily biodegradable).

 

Hydrocarbons, C13-C15, isoalkanes, cyclics, <2% aromatics biodegraded to an extent of 16.95% after 24 days and 20.62% after 31 days. Hydrocarbons, C13-C15, isoalkanes, cyclics, <2% aromatics is not inherently biodegradable.

 

Tetradecane biodegraded to an extent of approximately 80% after 28 days and 38 days. The data support characterizing tetradecane as rapidly biodegradable (readily biodegradable).

 

A persistence (P) screening assessment has been realized for tetradecane using EPI suite BIOWIN 2, 3 and 6 (v4.10) models, in accordance with Reach Guidance R.11. The Biowin 2 probability being 0.9797 > 0.5, and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months (value 3.3574 > 2.2), the criteria indicating that the substance does not biodegrade fast are not fulfilled. The Biowin 6 probability being 0.8799 > 0.5 and the Biowin 3 ultimate biodegradation time frame being "days-weeks" < months, the criteria indicating that the substance does not biodegrade fast are not fulfilled. So, the biodegradation prediction by BIOWIN does not lead to the conclusion that Tetradecane would be persistent.

 

Biodegradation in water and sediment: simulation tests

 

Biodegradation in water

Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, biodegraded to an extent of 69% after 28 days in seawater that used the indigenous microorganisms in the seawater sample as a sole source of the inoculum.

 

Hydrocarbons, C12-C14, isoalkanes, <2% aromatics biodegraded to an extent of 11% in sea water after 28 days.

 

Biodegradation in soil

In accordance with column 2 of REACH Annex IX, the simulation testing on ultimate degradation in soil does not need to be conducted as the tested substances are readily biodegradable. Data is available from a Guideline (OECD 304 A) study conducted on Hydrocarbons, C11 -C14, n-alkanes, isoalkanes, cyclics, <2% aromatics and is presented below.

 

Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, biodegraded to a great extent (>60%) in a silt loam soil at a rate comparable to the control, rapeseed oil (62 to 67%), within a two month test period as measured in respirometric oxygen consumption tests. The half-life, based on three tests was 45 days. This extent was replicated in two separate studies.

 

Bioaccumulation: aquatic/sediment

Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, <2% aromatics are hydrocarbon UVCB's. 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 Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, <2% aromatics ranges from 44.60 - 5361.88 L/kg.

The BCFWIN v2.16 model within EPISuite 3.12 has been used to estimate the bioaccumulation potential of a number of representative substances. This data is used as a weight of evidence alongside the data reported above.

The calculated BCF of decane is 144.3 L/kg. This value indicates that decane is not considered a bioaccumulative substance.

The calculated BCF of undecane is 337.8 L/kg. This value indicates that undecane is not considereda bioaccumulative substance.

The calculated BCF of dodecane is 790.9 L/kg. This value indicates that dodecane is not considered a bioaccumulative substance.

The calculated BCF of tetradecane is 962.9 L/kg. This value indicates that tetradecane is not considered a bioaccumulative substance.

 

Bioaccumulation: terrestrial

This endpoint has been calculated for representative hydrocarbon structures including the substances in Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, < 2% aromatics using the BCFWIN v2.16 model within EPISuite 3.12 as input to the hydrocarbon block method incorporated into the PETRORISK model. The predicted BCFs for hydrocarbons are generally overly conservative since biotransformation is not quantitatively taken into account. Therefore, indirect exposure and resulting risk estimates predicted by PETRORISK are likely to be overestimated. For the purposes of PBT assessment, measured bioaccumulation data for representative hydrocarbon constituents including the substance have been used as detailed in PETRORISK spreadsheet attached to IUCLID section 13.

 

Adsorption / desorption:

Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, <2% aromatics are hydrocarbon UVCB's. 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 Koc for Hydrocarbons, C10 -C13, n-alkanes, isoalkanes, cyclics, <2% aromatics ranges from 4.68 x10^2 - 8.91 x10^5.

Volatilisation:

Volatilisation is dependent on Henry's Constant (HC) which is not applicable to complex substances. However, HC values for representative structures are included in the PETRORISK spreadsheet attached to IUCLID Section 13.

 

Henry's law constant for decane has been estimated in the Concawe library, using SPARC v4.2 program. The obtained value is 3.311 atm-m3/mol.

 

Henry's law constant for undecane has been estimated in the Concawe library, using SPARC v4.2 program. The obtained value is 4.47 atm-m3/mol.

 

Henry's law constant for dodecane has been estimated in the Concawe library, using SPARC v4.2 program. The obtained value is 6.17 atm-m3/mol.

 

Henry's law constant for tetradecane has been estimated in the Concawe library, using SPARC v4.2 program. The obtained value is 11.48 atm-m3/mol.

 

Distribution modelling 

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C9-C11, n-alkanes, isoalkanes, cyclics, <2% aromatics is 80.0 % to air, 3.6 % to water, 3.4 % to soil and 13.0 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C9-C11, isoalkanes, cyclics, <2% aromatics is 69.5 % to air, 5.5 % to water, 5.2 % to soil and 19.8 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of decane is 48.62 % to air, 5.98 % to water, 9.49 % to soil and 35.91 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C10-C13, isoalkanes, cyclics, <2% aromatics is 46.1 % to air, 2.7 % to water, 15.1 % to soil and 36.1 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of of Hydrocarbons, C10-C14, (even numbered), n-alkanes, isoalkanes, <2% aromatics is 45.2 % to air, 2.5 % to water, 16.1 % to soil and 36.2 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of undecane is 41.8 % to air, 2.71 % to water, 8.17 % to soil and 47.32 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of dodecane is 39.52 % to air, 2.4 % to water, 20.04 % to soil and 38.04 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C12-C13, isoalkanes, cyclics, <2% aromatics is 28.0 % to air, 2.81 % to water, 22.03 % to soil and 47.04 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of Hydrocarbons, C13-C15, n-alkanes, isoalkanes, cyclics, <2% aromatics is 3.9 % to air, 1.1 % to water, 8.9 % to soil and 86.1 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of tetradecane is 4.25 % to air, 0.61 % to water, 7.83 % to soil and 87.31 % to sediment.

 

Based on the regional scale exposure assessment, the multimedia distribution of hexadecane is 5.13 % to air, 0.1 % to water, 89.03 % to sediment and 5.74 % to soil.

 

Based on the regional scale exposure assessment, the multimedia distribution of isododecane is 39.52 % to air, 2.4 % to water, 20.04 % to soil and 38.04 % to sediment.

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