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Bioaccumulation: aquatic / sediment

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Description of key information

Tridecylamine, branched and linear, does not fulfil the PBT and vPvB criteria (ESIS, 2008).

Key value for chemical safety assessment

Additional information

Tridecylamine, branched and linear (CAS 86089-17-0), has been deleted from the list of potential PBT/vPvB substances since the substance does not fulfil the PBT and vPvB criteria (ESIS, 2008). It is a mixture composed of (predominantly) groups of isomers with chain lengths ranging from C11 to C14 and, to a minor content, of C10 alkylamines. The main fraction are C13-amines, followed by the C12-, C11- and C14-amines.

GC/MS analysis confirmed the following relative distribution of the detected C10 to C14 alkylamines (BASF AG, 2005; normalized to 100%):

- C10-amines: 1%

- C11- amines: 12%

- C12-amines: 16%

- C13-amines: 68%

- C14-amines: 3%

The industry has conducted a pilot BCF study with n-hexadecylamine (C16 amine; CAS# 143-27-1) as a representative chemical for primary alkyl amines following the OECD TG 305 test design. The C16 amine was chosen because of its sufficient water solubility and the availability of an adequate analytical method. Due to variable exposure concentration, long study duration as well as significant adsorption of the substance to fish surfaces, complex considerations are required for the assessment of the true BCF.

In a report by the European Chemicals Bureau (ECB) dated October 2006 a PBT Working Group stated the BCF for the whole fish below 1200 L/kg, indicating that the substance does not fulfil the "B"-criteria for substances with bioaccumulation potential of high concern (PBT list no. 93, Rev. 13/14). This was a preliminary worst case estimation by using the nominal concentration in water as input parameter. During the uptake, the nominal concentration in water was 3 µg/L. After 11 months of exposure, the concentration in fish was ranging from 1,500 to 3,600 µg/kg (whole fish) and from 8,000 to 15,000 µg/kg for mucous/scales. It can be assumed that adsorption to surfaces of the subjects was included in the measurements.

Final results of this OECD 305 study performed by Akzo Nobel are stated in a position paper by APAG (2008). Here, the BCF was determined to be between 560 and 860 L/kg (excluding substance sorbed to the mucous and the scales). This BCF should be regarded as an indicative value as the mass balance could not be closed due to biodegradation and sorption of the test substance.

The latest report on the OECD 305 study was published by the Risk Assessment Committee (RAC) of the European Chemicals Agency (ECHA) in December 2011 (report no. ECHA/RAC/CLH-O-0000002198-71-01/F). In this report, the previous BCF evaluations for n-hexadecylamine (CAS# 143 -27-1) are supported by an estimated BCF of ≥ 500 L/kg. This BCF is based on the minimum measured exposure concentrations (50% of nominal = 1.5 µg/L) and the whole fish concentration after removal of the physically absorbed test item (mucous and scales). The authors of the RAC point out that growth of the exposed fish is likely to have been significant during the long exposure. Therefore, the measured fish concentrations may not represent a true steady state due to growth dilution. The RAC concluded that the BCF is likely to be in the region of 500 L/kg or above.

In addition, read-across from a weight-of-evidence approach with the analogue C13 substance 1-Tridecanamine (CAS 2869-34-3) indicates a low bioaccumulation potential of the test item Tridecylamine, branched and linear. Considering mitigating factors like metabolism the reliable models predict BCF values of clearly below 2000, indicating that the substance does not fulfil the "B"-criterion:

- A BCF calculation using the CATALOGIC v.5.11.15 BCF base-line model v02.08 is available. The BCF model calculates the BCF based on user-entered values for the n-octanol/water partition coefficient (log Kow) and the water solubility (WS). In this case, the BCF was calculated based on an estimated log Kow value of 5.25 (EPISuite KOWWIN v1.68, BASF SE 2014; referring to the uncharged molecule) and on the basis of three different WS values of 5.61 mg/L (estimated with WATERNT v1.01 for CAS 2869-34-3; BASF SE, 2014), 13.7 mg/L (estimated with WSKOW v1.42 for CAS 2869-34-3; BASF SE, 2014) and 40.0 mg/L (experimentally determined for CAS 86089-17-0; BASF AG, 1976). The base-line model considers the influence of mitigating factors like ionization of the molecule, water solubility and also size and metabolism. Based on the estimated WS value of 5.61 mg/L, the BCF is reduced from an initial value of 7852.4 (log BCF = 3.895) to 1096.5 (log BCF = 3.04); based on the estimated WS value of 13.7 mg/L, the BCF is reduced from an initial value of 7852.4 (log BCF = 3.895) to 1071.5 (log BCF = 3.03); based on the experimentally determined WS value of 40.0 mg/L, the BCF is reduced from an initial value of 7852.4 (log BCF = 3.895) to 1096.5 (log BCF = 3.04). In all cases, the estimated reduction of the BCF is mainly due to the mitigating factors molecular size and metabolism. In addition, the low water solubility slightly reduces the BCF as estimated. The test substance is to 100% within the applicability domain of the model (BASF SE, 2014).

 - EPI Suite v4.1/BCFBAFv3.01: Based on the estimated log Kow value of 5.25 (EPISuite KOWWIN v1.68, BASF SE 2014; referring to the uncharged molecule), a BCF value of 57.5 L/Kg was estimated with the submodel Meylan et al. (1997/1999). This BCF estimate can be regarded as accurate as the compound was within the applicability of the model, indicating that significant bioaccumulation in organisms is not to be expected.

Using the Arnot & Gobas (2003) method with included biotransformation rate estimates, the BCF was calculated to be 1280 L/kg (BASF SE, 2014). Although the substance was within the applicability domain of this submodel, the estimation may be less accurate due to the substance's property to appreciably ionize at physiological pH.

 - BCF calculations by three submodels of the VEGA tool v1.1.1 are available: The CAESAR model v2.1.14 estimated a BCF of 721 (log BCF = 2.86); the Meylan submodel v1.0.3 calculated the BCF at 58 (log BCF = 1.76); a BCF of 27 L/Kg (log BCF = 1.43) was estimated by the KNN/Read-Across submodel v1.1.0. The log Kow stated by CAESAR was 4.65 (MLogP), the BCF estimated by the Meylan model is based on a log Kow of 5.25 (KOWWIN).

All submodels predicted BCF values considerably lower 2000 L/Kg, indicating the test item not to fulfil the “B”-criterion. However, these predictions appear to be less accurate as the substance was not within the applicability domain of any of the submodels.

 - T.E.S.T. v4.1 (US EPA model): The methods were validated using statistical external validation using separate training and test data sets. The Consensus method averages the reasonable results from all applicable models. Following EPA, the Consensus method yields the best results in terms of prediction accuracy and coverage. Regarding the analogue substance 1-Tridecanamine (CAS 2869-34-3), the predicted BCF values range from 30.98 to 276.36. The Consensus method resulted in a BCF of 82.81 (BASF SE, 2014). The confidence in the results is low since the mean absolute errors (MAE) for the predictions for similar chemicals were higher than the MAE's for the entire set of chemicals. This applies to the external test set as well as to the training set.

The low potential of bioaccumulation of tridecylamine, branched and linear, is supported by a toxicokinetic study with mice performed by Fowler et al. (1976; see IUCLID Ch. 7.1.1). After injection of radiolabeled tridecylamine into mice, its fate in mice was followed. It was shown that the mice tended to concentrate the substance in lung tissue. The authors could also show that tridecylamine was metabolised (excretion of carbon dioxide). It was concluded that tridecylamine, like other monoalkylamines, undergoes oxidative deamination by monoamine oxidase and is further metabolised to carbon dioxide.

The low potential of bioaccumulation is also supported by a performed log Pow guideline study according to OECD 117. The log Pow of TDA, branched and linear was measured to be 1.5 to 2.3 at pH 7 and 23 °C (BASF, 2012; report No. 12L00366). However, the measured log Kow value is of limited value as surface tension properties of the molecule cannot be excluded (OECD 115: 29 mN/m at 20 °C (concentration 1 g/l).

In conclusion, the test item Tridecylamine, branched and linear is assessed to not fulfil the "B"-criterion.

 Table: Estimated BCF values for 1-tridecanamine (CAS 2869-34-3)

Model

BCF

In AD

Restraints

OASIS Catalogic v5.11.15

BCF baseline model v02.08: incl. mitigation factors

1096.5

yes

Water solubility: 5.61 mg/L

1071.5

yes

Water solubility: 13.7 mg/L

1096.5

yes

Water solubility: 40.0 mg/L

BCF baseline model v02.08: not considering mitigation factors

7852.4

yes

Water solubility: 5.61 mg/L

7852.4

yes

Water solubility: 13.7 mg/L

7852.4

yes

Water solubility: 40.0 mg/L

EPI Suite v4.11

BCFBAF v3.01: Meylan et al. (1997/1999)

57.5

yes

-

BCFBAF v3.01: Arnot-Gobas BCF, upper trophic level,

incl. biotransformation

1280

yes

The substance ionises appreciably; therefore, the estimation may be less accurate.

BCFBAF v3.01: Arnot-Gobas BCF, upper trophic level

not considering biotransformation (biotransf. rate = 0)

11640

yes

The substance ionises appreciably; therefore, the estimation may be less accurate.

US EPA

T.E.S.T. v4.1: Consensus method

82.8

yes

confidence in the predicted BCF is low

VEGA v1.1.1

CAESAR v2.1.14

721

no

-

Meylan v1.0.3

58

no

-

KNN/Read-Across v1.1.0

26.9

no

-

 

QSAR disclaimer

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 

For the assessment of tridecylamine, branched and linear (CAS 86089-17-0) (Q)SAR results were used for bioaccumulation. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 

Therefore and for reasons of animal welfare, further experimental studies on bioaccumulation are not provided.