Triethyl O-acetylcitrate

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:

2010-07-22 - 2010-11-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Principles of method if other than guideline:

None

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No surrogate or analogue material was used.

Analytical monitoring:

yes

Details on sampling:

- Sampling method/ concentrations: Approximately 50 mg test item were diluted with 50 mL acetonitrile to obtain stock solutions of 1 g test item/L. Appropriate amounts of these stock solutions were diluted with test water to obtain fortified samples at concentrations of 10 and 100 mg test item/L.
- Sample storage conditions before analysis: All samples were stored in a freezer (< - 10 °C), protected from light until analysis was performed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Controls: Test water without addition of the test item
Stock Solution: The test item was used to prepare the stock solution. 49.9 mg of the test item were diluted with 50 mL of acetonitrile to obtain a stock solution of approximately 1 g test item/L.
Standard Solutions: Appropriate amounts of the stock solution were diluted with a mixture
of acetonitrile/test water (50/50) to obtain standard solutions in the range from 2.5 to 75 mg test item/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: (Straus), clone 5
- Sex: Female
- Source: In-house laboratory culture
- Age at study initiation (mean and range, SD): From 5.75 to 21.75 hours old
- Method of breeding: The Daphnia were bred in the laboratories of the testing facility under similar temperature and light conditions as used in the test. The cultivation of the parental Daphnia was performed in reconstituted water of a similar quality with regards to pH, the constituent salts and total hardness as the test water used in the test. The test organisms were not first brood progeny.
- Feeding during test
- Food type: Green algae (Desmodesmus subspicatus) freshly grown in the laboratories of the testing facility.
- Frequency: Once a week the Daphnia in the stock culture were fed at least all working days.

ACCLIMATION
- Acclimation conditions (same as test or not): Acclimatisation was not necessary, since the test was performed in the same medium as the culturing.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

No post exposure observation period is described.

Hardness:

2.5 mmol/L (= 250 mg/L) as CaCO3

Test temperature:

21 °C at test start, 20 °C at test end (water temperature)

pH:

7.7 to 7.8 at test start, 7.8 at test end; and thus the pH-value did not vary by more than 1.5 units

Dissolved oxygen:

8.7 mg/L at test start; 8.1 to 8.3 mg/L at test end

Salinity:

No details available.

Nominal and measured concentrations:

The only concentration tested was nominal 100 mg test item/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beakers
- Type: closed
- No. of organisms per vessel: 20
- No. of vessels per concentration (replicates): one
- No. of vessels per control (replicates): one

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: In deionised water analytical grade salts and additives were added (main components are CaCl*2 H2O, MgSO4*7 H2O, KCl, NaHCO3, Na2SiO3*9 H2O, NaNO3, KH2PO4 and K2HPO4).
- Alkalinity: 0.9 mmol/L
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Photoperiod: 16 h light, 8 h dark
- Light intensity: The light intensity was 1000- 1100 lux (measured once during the test).

TEST CONCENTRATIONS
The only test concentration of 100 mg test item/L was prepared by dissolving 104 mg test item into 1040 mL test water by intense stirring for 90 minutes.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

24 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:

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.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Signs of intoxication after 24 hours: After 24 hours in the control and in the only test concentration of nominal 100 mg test item/L no immobilisation of the test animals was observed.
Signs of intoxication after 48 hours: Also after 48 hours of exposure no immobilisation of the test animals was observed in the control and in the only test concentration of nominal 100 mg test item/L.
Appearance of the test item in test water: No remarkable observations.

Results with reference substance (positive control):

In the most recent test with the reference item potassium dichromate performed in January 2010 the EC50 after 24 hours was determined to be 1.59 mg test item/L indicating that the sensitivity of the Daphnia was consistent with the level proposed by the OECD 202 guideline (EC50-24 h between 0.6 and 2.1 mg potassium dichromate/L).

Reported statistics and error estimates:

No statistical analysis was performed.

Validity criteria of the study

Control Immobilisation Rate: Was 0 % and furthermore no Daphnia showed signs of disease or stress; thus the validity criterion was met.

Dissolved Oxygen Concentration: Was > 8.1 mg O₂/L in the control and test vessels at the end of the test; thus validity criterion was met.

Analytical results

At the start of the test 109 % of the nominal test concentration was found. After 48 hours test duration, 94 % of the nominal value was determined. During the test the Daphnia were exposed to a mean of 101 % of nominal. Therefore, all reported results refer to nominal concentrations.

Validity criteria fulfilled:

yes

Remarks:

All validity criteria of the test method were met.

Conclusions:

The LOEC (48h) and the EC50 (48h) were determined to be > 100 mg test item/L, the NOEC (48h) was determined to be ≥ 100 mg/L.

Executive summary:

The acute toxicity to aquatic invertebrates of 'triethyl O-acetylcitrate' was tested according to OECD Guideline 202 and EU Method C.2 in a static 48-hour immobilisation limit test with Daphnia magna STRAUS as test organisms (Boettcher M., Wydra V., 2010). The study was conducted under certificated GLP compliance. The only concentration tested was nominal 100 mg test item/L. Additionally a control was tested in parallel (test water without addition of the test item). Thus a limit test was performed in accordance with OECD Guideline 202 to demonstrate that the test item has no toxic effect on the test animals up to this concentration. The immobility of the Daphnia (20 Daphnia per control and test concentration) was determined by visual observation after 24 and 48 hours, those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile (even if they could still move their antennae). After 48 hours of exposure no immobilisation of the test animals was observed in the control and in the only test concentration of nominal 100 mg/L. The 48-hour NOEC was determined to be ≥ 100 mg test item/L. The 48-hour LOEC was determined to be > 100 mg test item/L The 48-hour EC50 value was determined to be > 100 mg test item/L.

Description of key information

Daphnia magna:
Effect based on mobility: EC50 (48h) > 100 mg/L, NOEC (48h) ≥100 mg/L, LOEC (48h) > 100 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

The acute toxicity to aquatic invertebrates of 'triethyl O-acetylcitrate' was tested according to OECD Guideline 202 and EU Method C.2 in a static 48-hour immobilisation limit test with Daphnia magna STRAUS as test organisms (Boettcher M., Wydra V., 2010). The study was conducted under certificated GLP compliance. The only concentration tested was nominal 100 mg test item/L. Additionally a control was tested in parallel (test water without addition of the test item). Thus a limit test was performed in accordance with OECD Guideline 202 to demonstrate that the test item has no toxic effect on the test animals up to this concentration. The immobility of the Daphnia (20 Daphnia per control and test concentration) was determined by visual observation after 24 and 48 hours, those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile (even if they could still move their antennae). After 48 hours of exposure no immobilisation of the test animals was observed in the control and in the only test concentration of nominal 100 mg/L. The 48-hour NOEC was determined to be > 100 mg test item/L. The 48-hour LOEC was determined to be > 100 mg test item/L The 48-hour EC50 value was determined to be > 100 mg test item/L.