Amines, C11-14-branched alkyl, monohexyl and dihexyl phosphates

Bioaccumulation: aquatic / sediment

Description of key information

The test item is not bioaccumulative according to PBT criteria

Additional information

QSAR results

 

Mono-hexylphosphate

 

QSAR model		BCF	Domain
Catalogic v5.11.5; BCF base-line model v02.05		3.17	45.45% in
T.E.S.T. v4.0.1 Consensus method		0.85	In
VEGA	CAESAR v2.1.13	3	Out
	Meylan v1.0.2	3	Out
	Read-Across v1.0.2	4	Out
UBA		6	logKow within recommended range
EPISuite	Regression-based estimation	6.55	In
	Arnot-Gobas upper trophic	4.95	In
Additional information		value
Log Kow		1.74
Diammax aver		1.14 nm
Mol weight		182.15

 

Di-hexylphosphate

QSAR model		BCF	Domain
Catalogic v5.11.5; BCF base-line model v02.05		4.49	88.24% in
T.E.S.T. v4.0.1 Consensus method		6.63	In
VEGA	CAESAR v2.1.13	27	Out
	Meylan v1.0.2	22	Could be out
	Read-Across v1.0.2	9	In
UBA		818	logKow within recommended range
EPISuite	Regression-based estimation	1.88	In
	Arnot-Gobas upper trophic	277.9	In
Additional information		value
Log Kow		4.25
Diammax aver		1.69 nm
Mol weight		266.30

 

Di-tridecylamine branched

QSAR model		BCF	Domain
Catalogic v5.11.5; BCF base-line model v02.05		7.43	88.89% in
T.E.S.T. v4.0.1 Consensus method		226.51	In
VEGA	CAESAR v2.1.13	24	Out
	Meylan v1.0.2	3	Out
	Read-Across v1.0.2	122	In
UBA		616 – 23271	logKow within recommended range
EPISuite	Regression-based estimation	10	In
	Arnot-Gobas upper trophic	180	In
Additional information		value
Log Kow		8.07
Diammax aver		1.84 nm
Mol weight		382.71

 

Di-tridecylamine linear

QSAR model		BCF	Domain
Catalogic v5.11.5; BCF base-line model v02.05		8.20	82.76% in
T.E.S.T. v4.0.1 Consensus method		82.10	In
VEGA	CAESAR v2.1.13	7	Out
	Meylan v1.0.2	3	Out
	Read-Across v1.0.2	21	In
UBA		12983	logKow within recommended range
EPISuite	Regression-based estimation	70.8	In
	Arnot-Gobas upper trophic	99.29	In
Additional information		value
Log Kow		8.51
Diammax aver		3.39 nm
Mol weight		383.72

The bioaccumulation potential of CAS 80939-62-4 was assessed in a weight of evidence approach using different QSAR models as well as other parameters, i.e. log Kow and Diammax aver. Some representative structures were not in the domains of some QSAR tools. Moreover, the UBA model does not take mitigating factors, e.g. water solubility or metabolism, into account. Therefore, these results should only be taken into account with reservation. Experimental data are not available.

The compound is a UVCB substance consisting of negatively charged mono- or dihexylphosphate and positively charged di-tridecylamine in various C-chain compositions.

According to the QSAR results the mono-hexylphosphate part of the compound is not expected to accumulate in organisms. The QSAR BCF results are all well below 100. Additionally, the substance has a calculated log Kow of 1.74 which is clear proof of the compound’s non-bioaccumulative potential.

The di-hexylphosphate revealed similar results. None of the applied QSAR models gave alarming results. The calculated BCF values were well below 100 with the exception of one of the UBA models. Here a BCF of 818 was calculated. This result takes only the calculated log Kow of 4.25 into account and should therefore not to be overestimated. The read across approach of the VEGA tool delivered interesting results. According to this model different structurally similar compounds with existing experimental BCF values are available. The three most similar compounds were CAS 126-73-8, CAS 298-07-7 and CAS 78-42-2). Neither of these compounds have experimentally derived BCF values of greater than 20. Therefore, it can be assumed that the target compound has a BCF in a similar range. Taking all the available data into account this compound is not regarded to significantly accumulate in organisms.

Taking the raw materials of the production process into account, branched di-tridecylamine (in contrast to linear di-tridecylamine) is most likely the dominating isomer.

With the exception of the UBA models the results for branched di-tridecylamine were clearly below 300. The VEGA read across tool delivered similar structures with known experimental values. The most similar structure delivered by the model was CAS 1116-76-3 which has an experimentally derived BCF of 93. It is assumed that the BCF of the target compound is in a similar range. The log Kow of the compound was within the recommended range of two of the UBA models which revealed values of 616 and 23271, respectively. As mentioned above, these models only use the (calculated) log Kow of the compound and do not take mitigating factors into account. Therefore, these results are not considered in the weight of evidence approach. Branched di-tridecylamines have an average maximum diameter of 1.84 nm which is additional proof that this isomer has a limited potential to cross biological membranes.

Linear di-tridecylamines revealed QSAR results below 100. Again, the VEGA read across model delivered structurally similar compounds (CAS 1116-76-3, CAS 4051-66-5 and CAS 110-30-5) with BCF values below 93. The target compound’s BCF is believed to be in a similar range. Out of the different tools only one UBA model delivered a BCF value of 12983 which is not taken into account due to the above mentioned limitations of the model. Additionally this isomer has a very limited potential to cross biological membranes due to an average maximum diameter of 3.39 nm.

In summary, representative structures of the uvcb substance were assessed in a weight of evidence approach to judge their potential to bioaccumulate. Neither the hexylphosphate part nor the tridecylamine part of the substance was found to have an increased potential to bioaccumulate. The BCF values of the representative structures are all clearly below the PBT cut-off criterion of 2000. Furthermore, under environmental conditions the single compounds are negatively (hexylphosphate) or positively (tridecylamine) charged which further decreases the potential to bioaccumulate.

In conclusion, significant accumulation in organisms is not to be expected.