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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Parent compound pivaloyl chloride (CAS 3282-30-2): Low bioaccumulation potential based on log Kow < 3.

Hydrolysis product pivalic acid (CAS 75-98-9): Low bioaccumulation potential based on low BCF and log Kow < 3 and.

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 the hydrolysis product neodecanoic acid (CAS 26896-20-8) (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 REACH Regulation (EC) 1907/2006, Annex IX, Section 9.3.2, Column 2, the study does not need to be conducted since the substance and its hydrolysis product have a log Kow less or equal than 3. Based on the log Kow of 0.89 estimated for pivaloyl chloride (see IUCLID Ch. 4.7) bioaccumulation is not to be expected in aquatic organisms. However, the test substance rapidly hydrolyses and forms pivalic acid which has an experimentally determined log Kow of 1.8 (Hexxion, 1983) indicating that bioaccumulation of the hydrolysis product is not to be expected in aquatic organisms. In addition, a bioaccumulation study is not required under REACH for this tonnage band. Therefore, and in terms of animal welfare, no experimental tests on bioaccumulation in fish are provided.

 

However, a BCF calculation using the BCF base-line model v4.11 (OASIS CATALOGIC v.5.14.1.5, November 2019) is available for the hydrolysis product pivalic acid (CAS 75-98-9). Considering a measured log Kow of 1.8 (Hexxon, 1983), the model estimated a BCF of 31.2 L/kg without considering any mitigation factors. However, metabolism, acids and, for a minor part water solubility and molecular size reduce the log BCF to 3.6 L/kg as estimated by the model. The substance is 100% within the parameter domain and 100% within the mechanistic domain of the model. However, the substance is not entirely within the structural fragment domain due to 14% fragments not present in the training set. (BASF SE, 2021).

 

Based on these results bioaccumulation in aquatic organisms is not expected for pivaloyl chloride and the hydrolysis product pivalic acid.

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