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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Significant accumulation in organisms is not to be expected.

Key value for chemical safety assessment

Additional information

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 N,N,N',N'-Tetramethylhexamethylenediamine (TMHDA) (Q)SAR results were used for aquatic 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 aquatic bioaccumulation are not provided.

Assessment:

In accordance with column 2 of REACH Annex IX, the study does not need to be conducted since the substance has a log Kow less or equal than 3. TMHDA has a measured log Kow of 1.99 (23°C, pH: 12; BASF SE 2013; report no. 11L00324).

 

However, in order to assess the bioaccumulation potential of the test substance, the BCF was calculated with several estimation models. The table below lists the applied (Q)SAR models, the estimated BCF values and basic information on the applicability domain (AD). Detailed information on the model’s results and the AD are given in the endpoint study records of IUCLID Chapter 5.3.1. The selected models comply with the OECD principles for (Q)SAR models.

 

Summary of relevant information on aquatic bioaccumulation: Predicted BCF values for applied QSAR models sorted by BCF:

(AD = Applicability Domain)

Model

BCF

In AD

Restraints

BCF baseline model v.02.09 (OASIS Catalogic v5.11.19): incl. mitigating factors

2.34

yes

-

BCFBAF v3.01 (EPI Suite v4.11): Arnot-Gobas BCF, upper trophic, incl. biotransformation

3.4

no

- the substance ionizes at physiologically relevant pH

 

BCF KNN/Read-Across v1.1.0 (VEGA v1.1.3)

3.5

unclear

- the maximum error in prediction of similar molecules has a moderate value, considering the experimental variability

Meylan v1.0.3 (VEGA v1.1.3)

6

unclear

- only moderately similar compounds with known experimental value have been found

- reliability of logP value is not optimal

CAESAR v2.1.14 (VEGA v1.1.3)

7.0

no

- only moderately similar compounds with known experimental value have been found

- accuracy of prediction for similar molecules is not optimal

- the maximum error in prediction of similar molecules has a high value considering experimental variability

BCFBAF v3.01 (EPI Suite v4.11): Meylan et al. (1997/1999)

9.55

yes

-

US EPA T.E.S.T. v4.2.1: Bioaccumulation: Consensus method

9.92

yes

Based on the mean absolute errors of the models the confidence in the predicted results is high.

BCFBAF v3.01 (EPI Suite v4.11): Arnot-Gobas BCF, upper trophic, incl. biotransformation of zero

11.3

no

- the substance ionizes at physiologically relevant pH

BCF baseline model v.02.09 (OASIS Catalogic v5.11.19): not considering mitigating factors

39.6

yes

-

 

Considering all models applied the estimated BCF values range from 2.34 to 39.6 L/kg. Based on the available information on the log Kow (log Kow = 1.99; measured; BASF SE 2013, report no. 11LL00324) and supported by a weight-of-evidence approach from calculated data, it can be concluded that significant accumulation in organisms is not to be expected.