N,N,N',N'-tetramethylethylenediamine

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-11-29 to 2018-03-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identity: TMEDA, termed ATMEDAHP in the report
Purity: 99.9%
Batch number: 17F-1069978
C content: 62.01% (calculated)
Appearance: Liquid / colourless to yellow

Analytical monitoring:

yes

Details on sampling:

Analytical samples were taken from all test item concentrations and the control at test start and after 24 hours from fresh and aged solutions and after 48 hours from aged solutions. All samples were stored deep frozen until they were transferred to the analytical laboratory.

Vehicle:

not specified

Details on test solutions:

Nominal test concentrations were based on the results of a non GLP range-finding test.

Glass vessels used for preparation of the dilution series were saturated with test item for 24 hours before the test.

The necessary amount of test item for preparing the stock solution S1 was weighed on a weighing scoop and transferred to a volumetric flask. Test medium was added up to the bench mark and the solution was homogenised by shaking. Afterwards the solution was clear and transparent. Lower test solutions were prepared by dilution of the appropriate solution with test medium. ~ 50 mL of the prepared solutions were transferred to each test vessel.

Test organisms (species):

Daphnia magna

Details on test organisms:

The daphnids are continuously bred in the laboratory and were originally purchased in a healthy condition from the Federal Environment Agency in Berlin/Germany.
The daphnids were bred as single culture (1 daphnid per 100 mL) in Elendt M4 medium. The pH-value of the aerated water was within a range of 6.0 – 9.0. Dissolved oxygen was above 60 % saturation and the total hardness 140 - 250 mg/L (as CaCO3), corresponding to 7.8 - 14°dH. The daphnids were fed with single cell green algae (Desmodesmus subspicatus, formerly Scenedesmus subspicatus) at least three times a week.
The daphnids were reared at a temperature of 20 ± 2 °C in a climatic chamber with 16 hours of illumination and 8 hours of darkness. The medium was changed three times per week. A pipette was used to separate the young daphnids from the adults.
Freshly hatched daphnids less than 24 hours old were used for the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not relevant.

Hardness:

13°dH (232 mg/L as CaCO3)

Test temperature:

19.4 – 21.0 °C

pH:

7.46 – 9.41

Dissolved oxygen:

≥ 8.7 mg/L

Salinity:

NA

Conductivity:

Not reported

Nominal and measured concentrations:

Nominal concentrations: 6.25, 12.5, 25.0, 50.0, 100 mg/L, and control.

Details on test conditions:

Exposure to light: 16 hours photoperiod / 8 hours darkness daily
Feeding: none
Test vessels: four 50 mL glass beakers per treatment, each filled with ~ 50 mL, one additional replicate for physico - chemical measurements without test organisms
Loading: ~10 mL of test solution for each animal
Aeration: none
Number of animals: 20 per treatment in 4 replicates of 5

The test temperature and the pH-value as well as the oxygen concentration of the test solutions were measured at all concentrations at 0 and 24 hours from fresh test solutions and after 24 and 48 hours from aged test solutions in one separate replicate per test item concentration without test organisms. Hardness of the test water was measured on the day of application.

After 24 and 48 hours the immobilised daphnids were counted. All daphnids not able to swim within 15 seconds after gentle agitation of the test vessel were considered to be immobilised. If present, behavioural changes of daphnids were recorded at 24 and 48 hours after starting the test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate: 1.00 and 2.00 mg/L test concentrations with 20 test organisms per test concentration.

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 76 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

actual

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

38.5 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

actual

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 76 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

actual

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

38.5 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

actual

Basis for effect:

mobility

Details on results:

After 24 hours of exposure no immobilisation was observed in the control and up to and including 50.0 mg/L. 25 % immobilisation was observed at the highest test item concentrations of 100 mg/L.
After 48 hours of exposure no immobilisation was observed in the control and up to and including 12.5 mg/L. No immobilisation higher than the allowed control immobilisation was observed at 25.0 and 50.0 mg/L. At the highest test item concentration of 100 mg/L 30 % of the daphnids were found to be immobile.
No behavioural changes could be observed.

Results with reference substance (positive control):

Results from the reference substance, potassium dichromate, indicated an EC50 (24 h) between 1.00 and 2.00 mg/L. Since the results are in accordance with the requirements of the OECD guideline 202 and fall within the historical data generated with the reference item at the testing facility, the daphnids were suitable for the determination of the toxicological effects of the test item.

Reported statistics and error estimates:

The values for EC50 were not determined statistically. The NOEC was established based on the highest concentration at which the immobilisation is not higher than the allowed control immobilisation (≤ 10 % immobilisation).

Measured concentrations of TMEDA during an acute toxicity test with D. magna under semi-static conditions

Nominal TMEDA concentration (mg/L)	Measured concentration (mg/L) /[% of nominal]
	0 h (fresh)		24 h (expired)		24 h (fresh)		48 h (expired)		geomean
0 (control)	< LOD	[-]	< LOD	[-]	< LOD	[-]	< LOD	[-]	< LOD	[-]
6.25	5.23	[84]	5.23	[84]	4.80	[77]	4.99	[80]	5.06	[81]
12.5	10.5	[84]	9.44	[76]	8.85	[71]	8.89	[71]	9.40	[75]
25.0	21.3	[85]	20.2	[81]	17.5	[70]	17.4	[70]	19.0	[76]
50.0	42.7	[85]	40.2	[80]	35.9	[72]	36.7	[73]	38.8	[77]
100	85.0	[85]	81.5	[82]	71.8	[72]	66.3	[66]	75.8	[76]

 

Immobilisation of D. magna following 24 h exposure to TMEDA under semi-static conditions

	Nominal test item concentration [mg/L]
	Control	6.25	12.5	25.0	50.0	100
	Immobilised daphnids after 24 h
Group 1	0	0	0	0	0	1
Group 2	0	0	0	0	0	1
Group 3	0	0	0	0	0	1
Group 4	0	0	0	0	0	2
Σ	0	0	0	0	0	5
%	0	0	0	0	0	25

Immobilisation of D. magna following 48 h exposure to TMEDA under semi-static conditions

	Nominal test item concentration [mg/L]
	Control	6.25	12.5	25.0	50.0	100
	Immobilised daphnids after 48 h
Group 1	0	0	0	0	0	1
Group 2	0	0	0	1	1	1
Group 3	0	0	0	0	0	2
Group 4	0	0	0	1	1	2
Σ	0	0	0	2	2	6
%	0	0	0	10	10	30

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (48 h) was determined to be >100 mg/L (nominal) and >76 mg/L (actual, geomean measured). The corresponding NOEC (48 h) was 50.0 mg/L (nominal) and 38.5 mg/L (actual).

Executive summary:

The freshwater aquatic invertebrate, Daphnia magna, was exposed to TMEDA under semi-static conditions at nominal test concentrations of 0 (control), 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L. The study was conducted according to the OECD 202 Guideline at a GLP accredited laboratory and met the validity criteria prescribed by the study.

After 48 hours of exposure, immobilisation was 0, 0, 0, 10, 10 and 30% in the nominal 0 (control, 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L test item concentrations. The 48 hour EC50 for D. magna exposed to TMEDA was determined to be >100 mg/L (nominal) and >76 mg/L (actual, geomean measured). The corresponding 48 hour NOEC was 50.0 mg/L (nominal) and 38.5 mg/L (actual).

Description of key information

The freshwater aquatic invertebrate,Daphnia magna, was exposed to TMEDA under semi-static conditions at nominal test concentrations of 0 (control), 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L. The study was conducted according to the OECD 202 Guideline at a GLP accredited laboratory and met the validity criteria prescribed by the study.

After 48 hours of exposure, immobilisation was 0, 0, 0, 10, 10 and 30% in the nominal 0 (control, 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L test item concentrations. The 48 hour EC50 for D. magna exposed to TMEDA was determined to be >100 mg/L (nominal) and >76 mg/L (actual, geomean measured). The corresponding 48 hour NOEC was 50.0 mg/L (nominal) and 38.5 mg/L (actual).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

76 mg/L