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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-Dimethylacetamide (CAS 127-19-8) (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. N,N-Dimethylacetamide (CAS 127-19-8) has a log Kow of -0.77 (experimental value; at 25°C, HSDB, 2006).

 

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) for the compound. 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:

Model

BCF [L/kg]

In AD

Restraints

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

0.77

yes

Based on the mean absolute errors of the models compared to the training set data, the confidence in the predicted results is high.

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

0.9

no

the substance appreciably ionizes at physiologically relevant pH

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

0.9

no

the substance appreciably ionizes at physiologically relevant pH

CAESAR v2.1.14 (VEGA v1.1.3)

1

no

- only moderately similar compounds with known experimental been

found.

- the accuracy of the prediction for similar molecules is not optimal.

- some similar molecules have experimental values that disagree with the

predicted value.

- the maximum error in prediction of similar molecules has a moderate value.

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

1.15

yes

-

Meylan v1.0.3 (VEGA v1.1.3)

3

no

- only moderately similar compounds with known experimental value found.

- the maximum error in the prediction of similar molecules has a moderate

value.

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

3.16

yes

-

(AD = Applicability Domain)

 

Considering all models applied for the test substance, the estimated BCF values range from 0.77 (US EPA T.E.S.T. v4.2.1; substance within AD) to 3.16 L/kg (BCFBAF v3.01 (EPI Suite v4.11): Meylan et al. (1997/1999); substance within AD).

Base on the available data on the low log Kow of the substance and based on a weight-of-evidence approach by the available calculated BCF values, N,N-Dimethylacetamide (CAS 127-19-8) is concluded to not significantly accumulate in organisms.