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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The log Kow observed for di (2-hydroxypropyl)tallow amine using the slow-stirring method according to OECD 123, is 6.2 at pH 7 and 3.7 at a pH between 3 and 4.. For this product also a water solubility of 0.2 mg/L was observed. The measured log Kow value of 6.2 at pH 7 indicates that this substance may have a bioaccumulation potential if it would have been a narcotic substance and if the metabolic rate of the substance is not taken into consideration. For polar narcotics surface active substances like the primary fatty amine propoxylates however there is only limited information on the relationship between log Kow and BCF.

In addition di (2-hydroxypropyl)tallow amine is readily biodegradable and like the primary alkyl amine ethoxylates quickly metabolized by fish liver S9 it is therefore unlikely that they will accumulate in the food chain.  The bioaccumulation potential of primary fatty amine propoxylates should based on this be considered as low.

Key value for chemical safety assessment

BCF (aquatic species):
148.6 L/kg ww

Additional information

No measured BCF for fish is available for di (2-hydroxypropyl)tallow amine. Standard OECD 305 tests are technically not feasible with these sorbing and easily degradable substances. In addition is the route of exposure in a standard OECD 305 test unrealistic for these substances because the substance will either be sorbed or biodegraded. The bioaccumulation potential of primary fatty amine propoxylates was therefore assessed based on a measured log Kow. As indicated before, primary fatty amine propoxylates are readily biodegradable and it is therefore unlikely that they will accumulate in the food chain. Since there is a measured log Kow value available this value can be used to evaluate the bioaccumulation potential.

 

primary fatty amines propoxylates

Measured Log Kow

(at pH 7)

Measured Log Kow

(at pH 3 - 4)

Calculated

Log Kow

(EPIsuite)

Di (2-hydroxypropyl)hexadecylamine

5.7

3.3

3.93

Di (2-hydroxypropyl)octadecenylamine

6.1

3.6

4.7

Di (2-hydroxypropyl)octadecylamine

6.9

4.4

4.9

Di (2-hydroxypropyl)tallow amine

6.2

3.7

4.5

 

The log Kow observed for di (2-hydroxypropyl)tallow amine is 6.2 at pH 7 and 3.7 at a pH between 3 and 4.. For this product also a water solubility of 0.2 mg/L was observed. The measured log Kow value of 6.2 at pH 7 indicates that this substance may have a bioaccumulation potential if it would have been a narcotic substance and if the metabolic rate of the substance is not taken into consideration. For polar narcotics like the primary fatty amine propoxylates however there is only limited information on the relationship between log Kow and BCF.

For the primary alkyl amine, hexadecyl amine rapid metabilisation in fish is anticipated based on in vitro metabolism test results with this substance (Kmet= 0.152 1/d; Bernard et al., 2006). Based on the structural similarity and ready biodegradability of the primary fatty amine ethoxylates similar metabolisation rates are expected for the primary fatty amine propoxylates. According to the REACH PBT guidance R.11, evidence of high biotransformation/metabolisation rate in fish may be used to support for arguing for a limited bioaccumulation potential but quantitative thresholds have not been established. The use of QSAR- and mechanistically-based bioaccumulation models is also considered valuable in the overall bioaccumulation assessment process. The BCFBAF model (v3.0) as included in EPIsuite (v4.0) allows the inclusion of metabolism into the BCF calculation but the results of this model should be considered with care as the training set holds only a limited number of substances which can reliably be used to predict the fate of cationic surfactants. With a log Kow of 6.2 the BCFBAF model predicts a BCF of 20880 L/kg without metabolism and 148.6 L/kg with metabolism. The bioaccumulation potential of primary fatty amine propoxylates should based on this be considered as low.