1-(N,N-bis(2-ethylhexyl)aminomethyl)-1,2,4-triazole

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 2003 - March 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(1984)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

(1992)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sampling method:
For the analysis of the actual test item concentrations the following samples were taken:
Just before the start of the test:
- one sample from the freshly prepared stock solution
- duplicate samples from each test medium (without algae)
- duplicate samples from the control (without algae)
After 72 hours (stability samples):
- duplicate samples from each test medium (without algae)
- duplicate samples from the control (without algae)

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Hardness:

0.24 mmol/L (= 24 mg/L) as CaCO3

Test temperature:

23 °C

pH:

7.9 at test start
8.2-9.1 at test end

Nominal and measured concentrations:

Nominal: 0.01, 0.032, 0.10, 0.32 and 1.0 mg/L
Measured: nd, nd, nd, 0.25 mg/L, 0.96 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL Erlenmeyer flasks
- Fill volume: 15 mL algal suspension
- Initial cells density: 10,000 cells/mL
- Control end cells density: In the control, the cell density has increased from nominal N = 10,000 cells/mL at the start of the test (0 hours) to N = 1110000 cells/mL (mean value) after 72 hours
- No. of vessels per concentration (replicates): three replicates per test concentration
- No. of vessels per control (replicates): six replicates

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Photoperiod: Continuously illumination
- Light intensity and quality: about 8530 Lux (mean value)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter
Small volumes of the test media and the control (1.0 mL) were taken out of all test fiasks after 24, 48, and 72 hours exposure, and were not replaced. The algal cell densities in the samples were determined by counting with an electronic particle counter (Coulter Counter®, Model ZM), with at least two measurements per sample.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Test concentrations: 0.01, 0.032, 0.1, 0.32 and 1.0 mg/L

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: calculated for both parameters, the algal biomass (b) and the growth rate (r)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.66 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: nominal between 0.32 and 1 mg/L

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no abnomalities
- Unusual cell shape: no
- Colour differences: no

Reported statistics and error estimates:

The EC values were as far as possible calculated by linear interpolation between log-concentrations and %-responses of the two consecutive test concentrations with no (nominal 0.32 mg/L) and significant inhibifion (nominal 1.0 mg/L). The calculation of the EC values are based on the mean measured test item concentrations. For the determination of the LOEC and NOEC, the calculated mean biomass and the mean growth rate at the test concentrations were tested for significant differences when compared to the control values by a Dunnett-test.

Conclusions:

The NOErC 72h of the substance EC 401-280-0 and its hydrolysate is 0.32 mg/L

Description of key information

The NOErC 72h of the substance EC 401-280-0 and its hydrolysate is 0.32 mg/L

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.32 mg/L

Additional information

Parent substance EC 401 -280 -0

The toxicity of the substance EC 401-280-0 to algae was assessed according to OECD guideline 201. The 72-h ErC50 of algae exposed to the test item was determined to be higher than 1 mg/L (nominal), the NOErC 72h was determined to be 0.32 mg/L (nominal).

Hydrolysis products

bis(2 -ethylhexyl)amine

In a supporting algal growth inhibition test with the major hydrolysis product bis(2-ethylhexyl)amine conducted in 1990 a 72 -hour ErC50 of 1.55 mg/L and an ErC10 of 0.14 mg/L were determined (BASF AG d500/89, 1989, no solvent was used in this test). The value was recalculated from the fluorometric raw data in 2005 by ECT Oekotoxikologie GmbH in order to calculate the EC values relating to the growth rate, yield and biomass.

1H-1,2,4 -triazole

In supporting data on 1H-1,2,4 -triazole the ErC50 of 45mg/L and the ErC10 of 8.7 mg/L was determined (ECHA, 2014).

Formaldehyde

The acute toxicity of formaldehyde to algae was determined to be ErC50 = 4.89 mg/L (Eisenträger, 2003).

Therefore, the test substance is considered as acutely toxic to aquatic algae.