2-[[(butylamino)carbonyl]oxy]ethyl acrylate

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:

03 - 19 Feb 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)

Version / remarks:

13 Apr 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Swiss Federal Office of Public Health, Bern, Switzerland

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 3.42, 7.51, 16.5, 36.4, and 80.0 mg/L. Since the NOEC was higher than the nominal concentration of 3.42 mg/L, the two lowest concentrations (0.706 and 1.55 mg/L) were not analyzed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Since the test substance is soluble, the test solutions were prepared by dilution of a 80 mg/L stock solution in daphnia medium.
- Controls: Yes, containing test medium only.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Breeding: Parental and young daphnids held in 4 L glass aquaria (3 L medium) at 20 ± 2 °C. Illumination: 16 h per day; Medium: continuously aerated Elendt M4 medium prepared in deionised water (conductivity < 1.5 µS/cm)
- Age of daphnia at test start: < 24 h
- Feeding during breeding: Yes
- Food type: Suspension of Desmodesmus subspicatus in Elendt M4 medium with an optical density OD680 of about 15 units.
- Amount: 400 µL per daphnid per day
- Frequency: Every day, except on weekends

ACCLIMATION
- Acclimation period: 1 h
- Acclimation conditions: Same as test. Acclimatization to the test medium (Elendt M4 medium).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.52 mmol/L (total hardness, sum of Ca and Mg in Elendt M4 medium)
0.32 mmol/L (carbonate hardness in Elendt M4 medium)

Test temperature:

21.0 - 22.0 °C

pH:

6.7 - 7.3

Dissolved oxygen:

6.6 - 7.0 mg/L

Conductivity:

631 - 675 µS

Nominal and measured concentrations:

control, 3.42, 7.51, 16.5, 36.4, and 80 mg/L (nominal)
control, 3.50, 7.12, 16.1, 34.3, and 70.5 mg/L (geometric mean measured)

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL all-glass flasks filled with 50 mL test medium.
- Renewal rate of test solution: No renewal
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionised water
- Culture medium different from test medium: Culture medium same as test medium
- Intervals of water quality measurement: Temperature was determined in an additional flask without daphnids at the start and at the end of exposure. Oxygen and pH values were determined in the combined replicate solutions at the beginning and at the end of the exposure. Conductivity was determined in the combined replicate solutions at the beginning of the exposure.

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light per day
- Light intensity: Overhead white fluorescent tubes

EFFECT PARAMETERS MEASURED:
Immobilization: Observations after 24 and 48 h

RANGE-FINDING STUDY
- Test concentrations: 1, 10, and 100 mg/L (nominal)
- Results used to determine the conditions for the definitive study: Yes. After 48 h, immobilization was 20, 32.5, and 100% at concentrations 1, 10, and 100 mg/L (nominal), respectively.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

18.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence interval: 14.0 - 27.4 mg/L

Details on results:

- Other biological observations: No
- Mortality of control: 5% (48 h)
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes.
- Relevant effect levels: EC50 (24 h) = 1.3 mg/L potassium dichromate (04 Feb 2015)

Reported statistics and error estimates:

The ECx (x = 50, 20, 10) values for 24 and 48 h were calculated with ToxRat Standard Version 2.10 (ToxRat Solutions GmbH, Alsdorf, Germany).

ANALYTICAL RESULTS

HPLC analyses were performed at the beginning (0 h) and after 24 and 48 h of exposure.

The nominal concentrations tested were 3.42, 7.51, 16.5, 36.4, and 80.0 mg/L. The HPLC analyses showed that the concentrations were maintained within ± 20% of the nominal concentrations throughout the test: the geometric mean of the measured concentrations (GM0 -24h, GM0 -48h) corresponded to 88, 95, 99, 98, and 107% of the nominal values after 24 h and to 88, 94, 98, 95, and 102% of the nominal values after 48 h. As the NOEC was higher than the nominal concentration of 3.42 mg/L, the two lowest concentrations (0.706 and 1.55 mg/L) were not analyzed.

Therefore, the effective concentrations ECx and the no-observed-effect concentrations (NOEC) of the test substance were assessed based on the nominal concentrations.

BIOLOGICAL RESULTS

The ECx after 24 h of exposure could not be computed, due to lacking dose/response relationsip. However, the EC10 (24 h), EC20 (24 h) and EC50 (24 h) were estimated to be 16.5 - 36.4 mg/L. The NOEC (24 h) was 16.5 mg/L.

After 48 h of exposure, the EC50 (48 h) was calculated to be 18.6 mg/L (95% CI: 14.0 - 27.4 mg/L). The low effect concentrations EC10 (48 h) was 10.5 mg/L (95% CI: 3.90 - 14.0 mg/L) and the EC20 (48 h) was 13.2 mg/L (95% confidence limits: 7.02 - 16.9 mg/L). The NOEC (48 h) was 7.51 mg/L.

Table 1. Immobilization of Daphnia magna after 24 and 48 h of exposure.

Nominal concentration [mg/L]	Replicate	Number of individuals per test vessel	24 h Immobile daphnia (n°/vessel)	48 h Immobile daphnia (n°/vessel)	24 h % immobile daphnia	48 h % immobile daphnia
Blank control 0	A	20	0	0	0	0
	B	20	1	1	5	5
	C	20	0	0	0	0
0.706	A	20	0	0	0	0
	B	20	0	0	0	0
1.55	A	20	0	0	0	0
	B	20	0	0	0	0
3.42	A	20	0	0	0	0
	B	20	1	1	5	5
7.51	A	20	0	0	0	0
	B	20	0	0	0	0
16.5	A	20	0	7	0	35
	B	20	0	8	0	40
36.4	A	20	20	20	100	100
	B	20	20	20	100	100
80.0	A	20	20	20	100	100
	B	20	20	20	100	100

 

Description of key information

EC50 (48 h) = 18.6 mg/L (nominal, OECD 202, D. magna)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18.6 mg/L

Additional information

There is one key GLP study available investigating the effects of the substance towards aquatic invertebrates, which was conducted according to the OECD guideline 202.

In a static test, Daphnia magna was exposed to the five nominal test substance concentrations of 1.55, 3.42, 7.51, 16.5, 36.4, and 80.0 mg/L under controlled conditions for 48 h. Controls were run in parallel. Since the test substance is soluble, test solutions were prepared by the serial dilution of an 80 mg/L stock solution. The concentrations of the test substance were analytically verified by HPLC at 0, 24, and 48 h.

HPLC measurements showed that the test substance was fully dissolved. The geometric mean measured concentrations were 88 – 107% of the nominal concentration after 24 h and 88 – 102% of the nominal concentration after 48 h. These findings indicate that the test substance concentrations were stable for the duration of the test. Since the concentrations were within ± 20% of the nominal concentrations, the calculations of the effective concentrations ECx were based on the nominal concentrations.

After 48 h of exposure immobilization was observed. The calculated EC50 (48 h) value was 18.6 mg/L and the EC10 (48 h) was 10.5 mg/L (nominal). The NOEC (48 h) was 7.51 mg/L (nominal).