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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 C9-14 Aliphatics (≤ 2% aromatic) 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. C9-14 Aliphatics (≤ 2% aromatic) 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. C9-14 Aliphatics (≤ 2% aromatic) 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

Normal paraffins in the C9 to C14 Aliphatics Category (2% aromatics) are readily biodegradable, exhibiting 77 to 83% biodegradation in 28 days based on oxygen consumption and meeting the 10-day window.

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. These data are used as read-across data forC9-14 Aliphatics (≤ 2% aromatic).

Hydrocarbons, C12-C14, isoalkanes, <2% aromatics biodegraded to an extent of 11% in sea water after 28 days.These data are used as read-across data forC9-14 Aliphatics (≤ 2% aromatic).

Biodegradation in sediment

C9-14 Aliphatics (≤ 2% aromatic) arereadily biodegradable. Therefore, simulation tests in sediment are not required.

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 normal paraffinic substances representative of the C9-C14 Aliphatics Category (less than 2% aromatic) are readily biodegradable. However, 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. These data are used as read-across data toC9-14 Aliphatics (≤ 2% aromatic).

Bioaccumulation: aquatic/sediment

This endpoint has been calculated for representative hydrocarbon structures including the substances in theC9-14 Aliphatics (≤ 2% aromatic)category 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.

The QSAR used to calculated the BCF of C9-14 Aliphatics (≤ 2% aromatics) followed the Reach guidance indications (R7.10.3.2) and so is deemed suitable for the assessment of bioconcentration.

The calculated BCF of decane is 144.3 L/kg. This value indicates that decane is not to be considered as a bioaccumulable substance.

The calculated BCF of undecane is 337.8 L/kg. This value indicates that undecane is not to be considered as a bioaccumulable substance.

The calculated BCF of 790.9 L/kg indicates that dodecane does not belong to bioaccumulable substances.

The calculated BCF of tetradecane is 962.9 L/kg. This value indicates that tetradecane is not to be considered as a bioaccumulable substance.

Bioaccumulation: terrestrial

This endpoint has been calculated for representative hydrocarbon structures including the substances in the C9-14 Aliphatics (≤ 2% aromatic) category 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:

C9-14 Aliphatics (≤ 2% aromatic) 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 these substances with the PETRORISK model (see Product Library  in PETRORISK spreadsheet attached to Section 13).

Koc of decane has been estimated by calculation in the Concawe Library of Petrorisk, using SPARC v4.2 program (May 2008). The calculated value is 1.45 x10^4 L/kg, using a log Kow of 5.86.

Koc of undecane has been estimated by calculation in the Concawe Library of Petrorisk, using SPARC v4.2 program (may 2008). The calculated value is 5.62 x10^4 L/kg, using a log Kow of 6.42.

Koc of dodecane has been estimated by calculation in the Concawe Library of Petrorisk, using SPARC v4.2 program (May 2008). The calculated value is 1.10 x10^5 L/kg, using a log Kow of 6.98.

Koc of tretradecane has been estimated by calculation in the Concawe Library of Petrorisk, using SPARC v4.2 program (May 2008). The calculated valueis 7.59 x10^5 L/kg, using a log Kow of 8.11.

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:

The distribution ofC9-14 Aliphatics (≤ 2% aromatic)in the environmental compartments, air, water, soil, and sediment, has been calculated using the PETRORISK Model, version 5.2/5.3.Computer modeling is an accepted method for estimating the environmental distribution of chemicalsDistribution modelling results are included in the 'Multimedia distribution modelling results' tab in the PETRORISK spreadsheet attached to IUCLID section 13.

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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