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Environmental fate & pathways

Henry's Law constant

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Description of key information

From the water surface TEA will not evaporate into the atmosphere.

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
0
at the temperature of:
25 °C

Additional information

The Henry's Law constant of triethanolamine (TEA, CAS 102 -71 -6) was estimated using two calculation methods:

1) Vapour pressure/water solubility: 7.2E-8 Pa*m³/mol (HSDB; BASF SE, 2013)

2) EPI Suite v4.11 HENRYWIN v3.20: Bond contribution method: 4.2E-7 Pa*m³/mol.

As TEA is miscible with water, the calculation method is not suitable for the estimation of the HLC according to ECHA (2012). In case of the Bond Contribution method, TEA is outside of the applicability domain of the model as well. The bond correction factor for aliphatic alcohol function was exceeded by TEA (2 instead of instance). As the results from the above used methods are representative for the uncharged molecule. TEA has a pKa of 7.91 (SPARC v4.6). Therefore, the substance ionises in the environmentally relevant pH range. Using a correction factor, the Henry's Law constant can be estimated for the charged substance at pH 4 to 9. The pH-corrected HLC at pH 7 is calculated to be 4.6E-8Pa*m³/mol. The HLC in the environmentally relevant pH range is < 1 Pa*m³/mol.

In order to assess the evaporation of TEA from water to the atmosphere, a weight-of -evidence approach is applied. The available data indicate a very low Henry's Law constant leading to the conclusion that TEA will not evaporate from the water surface into the atmosphere. The HLC from the bond contribution method will be used in the risk assessment.

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 triethanolamine (CAS 102 -71 -6) (Q)SAR results were used for the estimation of the Henry's Law constant. 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, further experimental studies on the Henry’s Law Constant are not provided.