2-diethylaminoethanol

Endpoint summary

Additional information

Short-term toxicity to fish:

The short-term toxicity of 2-diethylaminoethanol to fish was investigated in a study according to guideline DIN 38412, part 15. Basically, the tests were conducted with non-neutralized test solutions; in addition, the acute toxicity was tested with neutralized medium at the highest nominal test concentration of 1000 mg/L (BASF AG, 1987). Based on nominal test concentrations, the 96-h LC50 was determined for non-neutralized test solutions as geometrical mean value to be 147 mg/L; the 96-h LC50 for neutralized the solutions was determined to be > 1000 mg/L, as no adverse effects could be observed at the highest concentration tested.

 

The nominal concentrations were 0 (control), 100, 215, 464, and 1000 mg/l; they were not analytically verified, but are assumed to be stable due to the the low n-octanol/water partition coefficient (log Kow = 0.21), the high water solubility (WS = 1.0E+06 mg/L at 23 °C), the moderate vapour pressure (VP = 2 hPa, at 22.4 °C) and the low Henry´s law constant (HLC, uncharged: 3.17E-04 Pa*m³/mol) of the chemical. Furthermore, the substance was found to be stable during a test on short-term toxicity to aquatic invertebrates according to OECD 202 (Atofina, 1993).

 

In addition, a further test on short-term toxicity to fish according to APHA (1980) standard methods for the examination of water and waste water which are similar to OECD 203 testing guideline showed an acceptable recovery of the test item in the neutralized test solutions. Based on nominal concentrations, the 96-h LC50 was 1780 mg/L (Geiger et al., 1986). 

 

With regard to the LC50, the effect values show a significantly higher toxicity using non-neutralized test solutions; therefore, the observed toxicity is partly due to the pH induced by the substance. For risk assessment the effect data for the neutralized test medium should be used, since the quantities of 2-diethylaminoethanol that would be found in natural waters are not likely to affect the pH to a relevant extend. It is likely that the EC50 value from the test without neutralization overestimates the potential toxicity of the target item.

 

Based on the data for neutralized test solutions (96-h LC50 > 1000 mg/L), the substance is assessed to be with high probability not harmful to fish.

 

Short-term toxicity to aquatic invertebrates:

The short-term toxicity of 2-diethylaminoethanol to aquatic invertebrates was investigated in a study according to EU Method C.2 (BASF AG, 1988). Based on nominal test concentrations the 48-h EC50 was determined to be 83.6 mg/L; the test solutions were not neutralized in this study.

 

The nominal concentrations were 0 (control), 7.81, 15.6, 31.2, 62.5, 125, 250, and 500 mg/l; they were not analytically verified, but are assumed to be stable due to the the low n-octanol/water partition coefficient (log Kow = 0.21), the high water solubility (WS = 1.0E+06 mg/L at 23 °C), the moderate vapour pressure (VP = 2 hPa, at 22.4 °C) and the low Henry´s law constant (HLC, uncharged: 3.17E-04 Pa*m³/mol) of the chemical. Furthermore, the substance was found to be stable during a test on short-term toxicity to fish conducted according to APHA (1980) standard methods for the examination of water and waste water which are similar to OECD 203 testing guideline (Geiger et al., 1986).

 

In addition, a further test on short-term toxicity to aquatic invertebrates according to OECD 202 (Atofina, 1993) showed an acceptable recovery of the test item in the test solutions. Based on nominal concentrations, the 48-h EC50 was 165 mg/L. 

 

With regard to the EC50, the effect values show a significantly higher toxicity using non-neutralized test solutions; therefore, the observed toxicity is partly due to the pH induced by the substance. For risk assessment the effect data for the neutralized test medium should be used, since the quantities of 2-diethylaminoethanol that would be found in natural waters are not likely to affect the pH to a relevant extend. It is likely that the EC50 value from the test without neutralization overestimates the potential toxicity of the target item.

 

Based on the data for neutralized test solutions (48-h EC50 = 165 mg/L), the substance is assessed to be with high probability not harmful to aquatic invertebrates.

 

Toxicity to aquatic algae and cyanobacteria:

The toxicity of 2-diethylaminoethanol to aquatic green algae and cyanobacteria was investigated in a study according to the german industrial standard test guideline DIN 38412, part 9 (Oekolimna, 1988). The original data were recalculated with ToxRat v2.10. Based on growth rate, the model recalculated the 72-h ErC50 to be 62.3 mg/L; the 72-h ErC10 was 21.4 mg/L. 

 

The nominal concentrations were 0 (control), 2, 5, 10, 20, 40, 80, 160 and 320 mg/L; they were not analytically verified, but are assumed to be stable due to the the low n-octanol/water partition coefficient (log Kow = 0.21), the high water solubility (WS = 1.0E+06 mg/L at 23 °C), the moderate vapour pressure (VP = 2 hPa, at 22.4 °C) and the low Henry´s law constant (HLC, uncharged: 3.17E-04 Pa*m³/mol) of the chemical. In addition, a test on short-term toxicity to fish conducted according to APHA (1980) standard methods for the examination of water and waste water which are similar to OECD 203 testing guideline (Geiger et al., 1986), as well as a further test on short-term toxicity to aquatic invertebrates according to OECD 202 (Atofina, 1993) showed an acceptable recovery of the test item in the test solutions.

Note:

The classification by long-term toxicity results is based on the 72-h ErC10 of 21.4 mg/L determined in the key study for algae (recalculated with ToxRat v2.10). According to the Guidance on information requirements and chemical safety assessment Chapter R.10: Characterisation of dose [concentration]-response for environment ", an EC10 for a long-term test which is obtained using an appropriate statistical method (usually regression analysis) will be used preferentially. [...] There has been a recommendation within OECD in 1996 to phase out the use of the NOEC, in particular as it can correspond to large and potentially biologically important magnitudes of effect. The advantage of regression method for the estimation of ECx is that information from the whole concentration-effect relationship is taken into account and that confidence intervals can be calculated. These methods result in an ECx, where x is a low effect percentile (e.g. 5-20%). It makes results from different experiments more comparable than NOECs".

The experimental results are supported by calculations resulting in the same effective concentration range, estimated with ECOSAR v1.11 implemented in EPISuite v4.11. The model calculated for 2-diethylaminoethanol a class-specific 96-h EC50 of 40.7 mg/L (Chronic value: 11.6 mg/L; ECOSAR class: Aliphatic Amines). The neutral organic SAR (baseline toxicity) was calculated to be 706.1 mg/L (96-h EC50) and 128 mg/L (chronic value). The substance is within the model's applicability domain.

Based on the available data, the substance is concluded to be acutely harmful to aquatic algae and cyanobacteria.

Toxicity to microorganisms:

In a short-term respiration test using domestic activated sludge (BASF AG, 1980) a 30-min EC20 of > 1000 mg/L was determined. Hence, the EC50 is also > 1000 mg/L.

The nominal concentration of 1000 mg/L was not analytically verified, but is assumed to be stable due to the the low n-octanol/water partition coefficient (log Kow = 0.21), the high water solubility (WS = 1.0E+06 mg/L at 23 °C), the moderate vapour pressure (VP = 2 hPa, at 22.4 °C) and the low Henry´s law constant (HLC, uncharged: 3.17E-04 Pa*m³/mol) of the chemical. In addition, a test on short-term toxicity to fish conducted according to APHA (1980) standard methods for the examination of water and waste water which are similar to OECD 203 testing guideline (Geiger et al., 1986), as well as a further test on short-term toxicity to aquatic invertebrates according to OECD 202 (Atofina, 1993) showed an acceptable recovery of the test item in the test solutions.