Dimethyl(octyl)amine

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:

10 - 29 Nov 2015

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:

Test item name: AD 1 Batch number. 4500083770EAS Test item code: M-00000740Appearance / colour: liquid / clearChemical name: N,N-dimethyloctylaminePurity (nominal): > 95 % w/w CAS number: 7378-99-6Molecular weight: 157.3 g/molRelative density (nominal): 0.765 g/cm³ Signal word(s): dangerIssue date of certificate: 21 Jan 2015Expiry date: 23 Sep 2016 Storage conditions: ambient ( ≤ +30 °C), dark, dry

Analytical monitoring:

yes

Details on sampling:

The analytical verification of test item concentrations in daphnid test medium was done by analysing the content of AD 1 in the samples during the test. Samples from control and all test item concentrations were analysed at test start t = 0 h from fresh test solutions and after 48 hours from aged test solutions.

Vehicle:

no

Details on test solutions:

The necessary amount of the test item for preparing the stock solution was weighed on weighing scoops and transferred to a volumetric flask. Test medium (see 4.3) was added up to the bench mark and the solution was homogenised by shaking. The solution was clear and an oily film was observed on the inner glass surfaces – this may have accounted for the lower actual (measured) concentrations. However, as a clear dose response was observed, study validity was not impacted. The lower test solutions were prepared by dilution of the stock solution. Defined volumes of the prepared solution were transferred to each test vessels. The test solution volume was 50 mL per test vessel.

Test organisms (species):

Daphnia magna

Details on test organisms:

As test organism, Daphnia magna STRAUS, Clone V, was used. The animals are continuously bred in the laboratory and were originally purchased in a healthy condition from the Federal Environmental Agency in Berlin/Germany.Daphnia magna was bred as single culture (one daphnid per 100 mL) in Elendt M4 medium. The pH-value of the aerated water was within a range of 6.0 – 9.0. The dissolved oxygen was above 60 % saturation and the total hardness 140 - 250 mg/L (as CaCO3), corresponding to 7.8 - 14°dH. The animals 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 h of illumination and 8 h 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:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

13 dH (232 mg/L CaCO3)

Test temperature:

20.2 - 20.6 °C

pH:

7.56 - 9.47

Dissolved oxygen:

≥ 7.6

Nominal and measured concentrations:

see table below

Details on test conditions:

Test procedure:staticDuration:48 hoursTemperature:20.2 – 20.6 °COxygen concentration:7.6 – 8.9 mg/LpH-value:7.56 – 9.47Exposure to light:16 hours photoperiod / 8 hours darkness dailyFeeding:noneTest vessels:four 100 mL glass beakers per concentration, each filled with 50 mL; one additional replicate for physico-chemical parameters without test organismsLoading:10 mL of test solution for each animal Aeration:noneNumber of animals: 20 per concentration in 4 replicates of 5

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

7.51 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

22.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

5.26 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

14.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

7.51 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

14.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

5.26 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

9.28 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Details on results:

After 24h of exposure no immobilisation was observed in the control and up to and including the nominal concentration of 7.51 mg/L. 35 % immobilisation was observed at 16.5 mg/L and 75 % immobilisation was observed at 36.4 mg/L while mobile specimen showed a decrease in movement speed. At the highest test item concentration of 80.0 mg/L all daphnids were found immobile.After 48h of exposure no immobilisation was observed in the control and at a nominal concentration of 3.42 mg/L. At 7.51 mg/L no immobilisation higher than the allowed control immobilisation was observed. At 16.5 mg/L 55 % of the daphnids were found immobile. At 36.4 mg/L and the highest test item concentration of 80.0 mg/L all daphnids were found immobile.

Results with reference substance (positive control):

The results indicate an EC50 (24 h) of the reference item potassium dichromate between 1.0 and 2.0 mg/L in the reference test. Since the results fall within the historical data generated with the reference item at the testing facility and the range recommended by the guideline (OECD 202), the daphnids were suitable for the determination of the toxicological effects of the test item.

Results of the test, 24 h values

Concentration Test Item	Control	3.42	7.51	16.5	36.4	80.0
		[mg/L]
	immobilised daphnids after 24 h
Group 1	0	0	0	3	3	5
Group 2	0	0	0	3	3	5
Group 3	0	0	0	0	4	5
Group 4	0	0	0	1	5	5
Σ	0	0	0	7	15	20
%	0	0	0	35	75	100

Results of the test, 48 h values

Concentration Test Item	Control	3.42	7.51	16.5	36.4	80.0
		[mg/L]
	immobilised daphnids after 48 h
Group 1	0	0	0	3	5	5
Group 2	0	0	0	3	5	5
Group 3	0	0	2	3	5	5
Group 4	0	0	0	2	5	5
Σ	0	0	2	11	20	20
%	0	0	10	55	100	100

Results of the toxic reference, started on 10 Nov 2015

	24 h			48 h
K2Cr2O7	1.0	2.0		1.0		2.0
[mg/L]	immobilised daphnids
Group 1	0		1	3	5
Group 2	0		5	1	5
Group 3	0		5	0	5
Group 4	0		3	4	5
S	0		14	8	20
%	0		70	40	100

Validity criteria fulfilled:

yes

Conclusions:

According to the results of the test, the EC50 (48 h) for immobilisation was determined to be 14.5 mg/L (nominal) and 9.28 mg/L (actual).The corresponding NOEC (48 h) was determined to be 7.51 mg/L (nominal) and 5.26 mg/L (actual).

Executive summary:

The initial measured concentration of AD 1 was between 55 and
88 % of nominal, the measured concentration in the aged solution was between 54 and 65 % of nominal. Therefore the toxicological endpoints were evaluated using nominal and actual concentrations of the test item.

Toxicological endpoints

Endpoint	AD 1 [mg/L] nominal
	24 h	48h
NOEC	7.51	7.51
EC50	22.8	14.5
95 % confidence limit of EC50	18.1 – 28.6	11.7 – 17.9
Endpoint	AD 1 [mg/L] actual*
	24 h	48h
NOEC	5.26	5.26
EC50	14.7	9.28
95 % confidence limit of EC50	11.7 – 18.4	7.68 – 11.6

*based on the geometric mean measured content of fresh and aged samples of each concentration level

The total hardness (as CaCO₃) of the untreated control was determined to be 13°dH (232 mg/L CaCO₃); the mean pH-value of the untreated control was determined to be7.67±0.11 (Std. Dev.), the mean temperature of the control and all test item concentrations was measured to be 20.4±0.2 °C (Std. Dev.) and the mean oxygen concentration was determined to be 8.6±0.5 mg/L (Std. Dev.).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

9.28 mg/L