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Toxicity to aquatic algae and cyanobacteria

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Description of key information

With high probability 2,2',2"-nitrilotriethanole is acutely not harmful to algae.

Key value for chemical safety assessment

EC50 for freshwater algae:
512 mg/L
EC10 or NOEC for freshwater algae:
26 mg/L

Additional information

The assessment of the algal toxicity is based on effect data taken from the “Commission for the Evaluation of Substances Hazardous to Waters” (KBwS) data sheet no. 201, which is part of the German Federal Water Act (Article 19g). Based on the collected data a substance is classified according to its water-hazardous properties (WGK 1 to 3). Triethanolamine was classified as WGK 1, which indicates a low hazard to waters. As the list with the classified substances was published in the Bundesanzeiger (Ref. 4), the classification is legally binding for the industry.

The data sheet lists three sources for effect data on algae (see table below) of which only one was performed according to a national standard method (Amann & Steinhäuser, Ref. 1) while the other two are of questionable reliability due to exposure period or documentation (Bringmann & Kühn, Ref. 2; Verschueren, Ref. 8).

Species

Not neutralised

Neutralised

Remark

Ref.

EC10

(mg/L)

EC50 (mg/L)

EC10 (mg/L)

EC50 (mg/L)

Desmodesmus subspicatus

7.9

216

26

512

DIN 38412, part 9; exposure: 72 h; based on growth rate

1

Scenedesmus quadricauda

EC3: 1.8

-

EC3: 715

-

Confusion between results for neutralised and not neutralised test results; here displayed correctly; exposure: 8 d (non-standard duration); no guideline followed

2

Scenedesmus

EC0: 100

-

-

-

No information regarding exposure duration and conditions; test species not clearly identified; based on growth rate

8

Additional information

Phaeodactylum tricornutum

> 10;

NOEC: < 28

204

-

-

Seawater species, ISO 10253; exposure: 72 h with light/dark cycle 16/8 h

7

Skeletonema costatum

-

>107 -<260

-

-

Seawater species, ISO 10253; exposure: 72-h, constant light

9, 10

Desmodesmus subspicatus

-

-

110

750

DIN 38412, part 9; exposure: 48 h

6

Colpoda

EC0: 160

-

-

-

No information regarding exposure duration and conditions; test species not clearly identified; based on growth rate

8

The data from Amann & Steinhäuser (Ref. 1) were generated within the research project “Assessment of Water-Hazardous Substances” which served the scientific support and administration of a “Commission” in their work of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety.

The algal toxicity tests were performed according to DIN 38412, part 9 (draft). Tests were performed in neutral medium unless noted otherwise. In case of triethanolamine, the test was performed with neutralised and not neutralised test medium in parallel. The test species wasScenedesmus subspicatus (new name: Desmodesmus subspicatus). The EC10 was determined being the relevant factor for the WGK classification. The effect data were evaluated based on growth rate in accordance with the information requirements of REACH.

The effect values show a higher toxicity using non-neutralised test medium; therefore, part of the observed toxicity is caused by the pH change due to the substance. For the risk assessment the effect data for the neutralised test medium should be used.

Detailed data on the study itself, e.g. biomass growth rate as well as growth curves are not available. Nevertheless the test results were performed according to national standards and peer-reviewed by the KBwS during the performance of the research project. Therefore, the data can be regarded as reliable with restrictions (RL 2) and should be used as key study for the risk assessment.

The result by Amann & Steinhäuser (1) is supported by the published effect values for a seawater algae Phaeodactylum tricornutum by Libralato et al. (2010) and the information on the seawater algae Skeletonema costatum published by Eide-Haugmo et al. (2009/2012). Other data which are available for triethanolamine do not contradict the selected key values, but should not be used for risk assessment purposes due to insufficient exposure duration and documentation.

The study performed by Amann & Steinhäuser was identified as key study. A 72-h ErC50 of 216 mg/l for non-neutralized samples and a 72-h ErC50 of 512 mg/l for a neutralized sample were determined onDesmodesmus subspicatusaccording to German Industrial Standard DIN 38412, part 9 (draft). The corresponding ErC10 values are 7.9 (non-neutr.) and 26 mg/L (neutr.). This result is supported by published data on a seawater algae (Phaeodactylum tricornutum; Libralato et al., 2010), which gave similar effect values in non-neutralised test solutions: EC50 = 204 mg/L; EC10 > 10 mg/L; NOEC < 28 mg/L. In addition, the seawater algae Skeletonema costatum (Eide-Haugmo et al., 2009/2012) also supports this level of sensitivity, although the EC50 could only be determined as a range of > 107 and < 260 mg/L.

Based on the presented data, it can be concluded that triethanolamine is acutely not harmful to algae.

References

1)      Amann W. & Steinhäuser KG (1986, 1988). 1. und 2. zusammenfassender Zwischenbericht zum F+E Vorhaben „Bewertung wassergefährdender Stoffe“ Teil I (FV-Nr. 82-102 05 308); Bayerisches Landesamt für Wasserwirtschaft, München [Interim Report, Evaluation of substances hazardous to water].

2)     Bringmann G. & Kühn R. (1977). Z Wasser Abwasser Forsch 10, 87-98.

3)     DIN 38412, part 9 (draft). German standard methods for the examination of water, waste water and sludge; bio-assays (group L); determination of the inhibitory effect of water constituents on the growth ofScenedesmusgreen algae (L 9).

4)     Federal Ministry of Justice (2005). Bundesanzeiger No. 142 a.

5)     ISO, Standard 10253 (2006). Water Quality—Marine Algal Growth Inhibition Test withSkeletonema costatumandPhaeodactylum tricornutum.

6)     Kühn R and Pattard M (1990). Results of the harmful effects of water pollutants to green algae (Scenedesmus subspicatus) in the cell multiplication inhibition test. Water Research 24(1), 31-38.

7)     Libralato G., Volphi Ghirardini A., Avezzù F. (2010). Seawater ecotoxicity of monoethanolamine, diethanolamine and triethanolamine. J Hazardous Materials 176, 535-539.

8)     Verschueren K. (1983). Handbook of environmental data on organic chemicals, 2nd edition. Van Nostrand Reinhold Company, New York.

9) Eide-Haugmo I, Brakstad OG, Hoff KA, Sorheim KR, Falck da Silva E, Svendsen HF (2009). Environmental impact of amines. Energy Procedia 1: 1297-1304.

10) Eide-Haugmo I, Brakstad OG, Hoff KA, Falck da Silva E, Svendsen HF (2012).Marine biodegradability and ecotoxicity of solvents for CO2-capture of natural gas. International Journal of Greenhouse Gas Control 9: 184-192