Tris(2-hydroxyethyl)ammonium salts of tall-oil fatty acids

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.023 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.23 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.002 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

PNEC marine water (intermittent releases):

0.023 mg/L

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.416 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.042 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.043 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Conclusion on classification

The substance is not classified for environmental hazards.

The UVCB substance WS400102 has a low eco-toxicological potential. Acute toxic effects to aquatic organisms were observed at concentrations above 10 mg/l. The PNEC (freshwater) for WS400102 was derived at a concentration of 0.023 mg/l. The UVCB substance WS400102 was readily biodegradable in the respective test. The substance has a log K_ow> 4 (log K_ow of the UVCB substance ranges from 2 to 5). However, classification as “aquatic chronic 3” is not appropriate and correct for this UVCB substance. The UVCB substance WS400102 is a salt (physical mixture) composed of (1) fatty acids, tall-oil, and (2) triethanolamine (with < 15% diethanolamine). This salt has a water solubility of ca. 250 mg/l.

(1) Tall-oil fatty acids are not classified as dangerous according to Regulation 1272/2008 (HARRPA, 2016). Tall-oil fatty acids were evaluated by US EPA in the frame of the High Production Volume (HPV) programme. It was concluded for these fatty acids that “the persistence and bioaccumulation rankings are low and that the acute hazard to aquatic organisms is low; long term hazard is not to be expected based on absence of persistence and of a bioaccumulation potential” (EPA, 2008). In the “Supporting Documents for Risk-Based Prioritization” published by EPA data on physical-chemical, eco-toxicological and toxicological properties as provided by industry are summarised. The following data on tall-oil fatty acids are taken from the document:

- water solubility:  12.6 mg/l

- log K_ow:  4.9-7.6 (pH2), 3.6-7.4 (pH7.5)

- bioconcentration factor:  10 (calculated for oleic and linoleic acid)

- ready biodegradability:  56-84%

(2) The other part of the UVCB substance WS400102, a salt, is triethanolamine (with < 15% diethanolamine).

Neither triethanolamine (EC no. 203-049-8) nor diethanolamine (EC no. 203-868-0) are classified as hazardous to the aquatic environment. Both substances are readily biodegradable and have a log K_ow < 0. The PNEC (freshwater) for triethanolamine and diethanolamine was derived at a concentration of 0.32 and 0.021 mg/l, respectively (information taken from the ECHA website on registered substances, accessed on 06 February 2020).

During the manufacture of the UVCB substance WS400102 also some esters (approx. 5%) are formed by condensation of fatty acids and triethanolamine (and diethanolamine). The environmental as well as eco-toxicological and toxicological properties of such esters were determined in detail and did not demonstrate a hazard to human health and the environment (CAS 67784 -78 -5).

Taking together the information on the raw materials used in the manufacture of the UVCB substance WS400102 and the information on the composition of WS400102 and its environmental as well as eco-toxicological and toxicological properties the following is concluded. The UVCB substance WS400102 exhibits low acute toxicity to the aquatic environment (EC50 values above 10 mg/l). This aquatic toxicity very probably is caused by diethanolamine that is contained in WS400102 at a concentration of approx. 5%. The PNEC derived for WS400102 amounts to 0.023 mg/l, which is the same as derived for pure diethanolamine (0.021 mg/l). The other components of WS400102, i.e. fatty acids, triethanolamine and esters, do not exhibit aquatic toxicity up to 100 mg/l or up to their limit of solubility.

Log K_ow of the UVCB substance WS400102 ranges from 2 to 5. The lipophilic substances are composed of fatty acids and their esters. These substances do not pose a hazard to the aquatic environment. Diethanolamine has a log K_ow< 0 and exhibits toxicity to aquatic organisms. Therefore, it is concluded that different components contained in the UVCB substance WS400102 contribute on the one hand to the acute aquatic toxicity and on the other hand to the (theoretical) bioaccumulation potential (log K_ow> 4). None of these different substances fulfills the criteria for classification as "aquatic chronic 3". Accordingly, the UVCB substance WS400102 is not classified for environmental hazards.

HARRPA (2016): Communication paper: REACH : Exemption of tall oil fatty acids (TOFA) from the obligation to register under Annex V.9.

EPA (2008): US Environmental Protection Agency: Supporting Documents for Initial Risk-Based Prioritization of High Production Volume Chemicals, Tall Oil Fatty Acids and Related Substances Category