(Z)-tetrahydro-6-(2-pentenyl)-2H-pyran-2-one

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:

24 April 2019 - 25 May 2019

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

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

(incl. certificate)

Details on sampling:

- Sample storage conditions before analysis: All samples were taken for immediate analysis. Duplicate sets of samples were taken at 0, 24 and 48 hours and stored frozen for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION OF TEST SOLUTION
A nominal amount of test item (200 mg) was dissolved in test water and the volume adjusted to 2 liters to give the 100 mg/L test concentration. From this test concentration, dilutions were made to give further test concentrations of 10, 18, 32 and 56 mg/L.
Each test solution was inverted several times to ensure adequate mixing and homogeneity.
The concentration and stability of the test item in the test preparations were verified by chemical analysis at 0, 24 and 48 hours

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: In-house laboratory
- Age at study initiation: less than 24 hours old
- Feeding during test : No

Test type:

semi-static

Water media type:

other: Reconstituted water (Elendt M4 medium)

Limit test:

no

Total exposure duration:

48 h

Test temperature:

18 to 22 °C

pH:

8.0 ±0.2

Dissolved oxygen:

9.3 - 9.7 mg O2/L

Nominal and measured concentrations:

The Range-finding Test
Nominal (mg/L): 0.10, 1.0, 10 and 100

The definitive test
Nominal (mg/L): 10, 18, 32, 56 and 100
Measured (geometric mean): (mg/L): 6.3, 12, 23, 42 and 77

Details on test conditions:

TEST SYSTEM
- Test vessel: 120 mL glass vessels
- Type: closed
- Volume of solution: 100 mL of test preparation were used
- Aeration: no
- Type of flow-through: semi-static
- Renewal rate of test solution (frequency/flow rate): Renewal at 24 hours, the test concentrations were freshly prepared and the daphnids transferred by wide bore pipette from the 24 Hour old test media into the fresh test media.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Reconstituted water (Elendt M4 medium) used for both the range finding and definitive tests
H3BO3: 57190 mg/L
MnCl2.4H2O: 7210 mg/L
LiCl: 6120 mg/L
RbCl: 1420 mg/L
SrCl2.6H2O: 3040 mg/L
NaBr: 320 mg/L
Na2MoO4.2H2O: 1260 mg/L
CuCl2.2H2O: 335 mg/L
ZnCl2: 260 mg/L
CoCl2.6H2O: 200 mg/L
Kl: 65 mg/L
Na2SeO3: 43.8 mg/L
NH4VO3: 11.5 mg/L
Na2EDTA.2H2O: 5000 mg/L
FeSO4.7H2O: 1991 mg/L

- Intervals of water quality measurement: The water temperature, pH and dissolved oxygen concentrations were recorded daily throughout the test. The measurements at 0 hours and after the test media renewal at 24 hours represent those of the freshly prepared test preparations while the measurements taken prior to the test media renewal, and on termination of the test after 48 hours, represent those of the expired or 24 hour old test preparations.

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods.
- Light intensity: between 200 and 1200 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Any immobilization or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilized if they were unable to swim within 15 seconds after gentle agitation.

RANGE-FINDING STUDY
- Test concentrations: In the range finding test Daphnia magna were exposed to a series of nominal test concentrations of 0.10, 1.0, 10 and 100 mg/L.
A nominal amount of test item (50 mg) was dissolved in test water and the volume adjusted to 500 mL to give the 100 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 0.10, 1.0 and 10 mg/L.
- Results used to determine the conditions for the definitive study: yes
Based on this information test concentrations of 10, 18, 32, 56 and 100 mg/L were selected for the definitive test.

CONCENTRATION
Analysis of the fresh test preparations at 0 and 24 hours showed measured test concentrations to range from 9.0 to 94 mg/L (88 to 94% of nominal concentrations). Analysis of the old/expired test preparations at 24 and 48 hours showed measured test concentrations had declined to range from 3.6 to 63 mg/L (36 to 66% of nominal concentrations), with the greatest losses typically occurring at the lower test concentrations. Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations in order to give a "worst case" analysis of the data.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

68 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

It was not possible to calculate 95% confidence limits for the EC50 value as the data generated did not fit the models available for the calculation of confidence limits

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

42 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No sub lethal effects of exposure were observed throughout the test

Results with reference substance (positive control):

- The results from the positive control with potassium dichromate were within the normal range for this reference item.
Time Point (Hours) 24
EC50: 1.1 mg/L, 95% Confidence Limits (mg/L) 0.95 - 1.3
NOEC: 0.56 mg/L
LOEC: 1.0 mg/L

Time Point (Hours) 48
EC50: 0.80 mg/L, 95% Confidence Limits (mg/L) 0.12 - 1.5
NOEC: 0.56 mg/L
LOEC: 1.0 mg/L

- A positive control test using potassium dichromate as the reference item was performed twice in a 12 month period to demonstrate satisfactory conditions of the test.

Reported statistics and error estimates:

- The EC50 values at 24 and 48 hours and the slope of the response curve and its standard error were calculated by Logit analysis using Linear Maximum Likelihood regression.
- The Lowest Observed Effect Concentration (LOEC) and the No Observed Effect Concentration (NOEC) at 24 hours were calculated using the Fisher’s Exact Binomial Test with Bonferroni correction and the NOEC and LOEC at 48 hours were calculated using Step-down Cochran-Armitage Test incorporating Tarone’s Test.
- All results were calculated using the ToxRat Professional computer software package (TOXRAT).

Analysis of the immobilization data by Logit analysis using Linear Maximum-Likelihood regression at 24 and 48 hours based on the geometric mean measured gave the following results:

Time (Hour)	EC50 (mg/L)	95% Confidence limits (mg/L)
24	91	Not determined*
48	68	Not determined

The NOEC after 24 and 48 hours exposure were >77 and 42 mg/L, respectively. The LOEC after 48 hours exposure was 77 mg/L.

The slopes and their standard errors of the response curves at 24 and 48 hours were 39 (standard error= 0.73) and 43 (standard error = 0.017) respectively. 

*It was not possible to calculate 95% confidence limits for the EC₅₀value as the data generated did not fit the models available for the calculation of confidence limits

Validation Criteria

The results of the test are considered valid if the following performance criteria are met:

• No more than 10% of the control daphnids show immobilization or other signs of disease or stress (e.g. discoloration or unusual behavior such as trapping at the surface water); none of the control daphnids showed immobilization or other signs of disease or stress.

• The dissolved oxygen concentration at the end of the test is equal to or greater than 3 mg/L in the control and test vessels; the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Validity criteria fulfilled:

yes

Conclusions:

Exposure of freshwater invertebrate Daphnia magna to the test item has been investigated and gave the following results based on the geometric mean measured test concentrations:

Time Point (Hours) 48
EC50: 68 mg/L
NOEC: 42 mg/L
LOEC: 77 mg/L

Executive summary:

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

 

Following a preliminary range‑finding test, 20 daphnids (4 replicates of 5 animals) were exposed to aqueous solutions of the test item at nominal concentrations of 10, 18, 32, 56 and 100 mg/L for 48 hours at a temperature of 20 °C to 21 °C under semi‑static test conditions. The number of immobilized Daphnia was recorded after 24 and 48 hours.

 

Exposure of Daphnia magna to the test item gave the following results based on geometric mean measured test concentrations:

Time Point (Hours)	EC50 (mg/L)	95% Confidence Limits (mg/L)	NOEC (mg/L)	LOEC (mg/L)
48	68	Not determined	42	77

Description of key information

48 hour toxicity study:

EC₅₀(immobilisation): 68 mg/L

NOEC (immobilisation): 42 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

68 mg/L

Additional information

A determination of the acute toxicity to aquatic invertebrates of Jasminlactone was conducted. The study was performed in accordance with EC method C.2 and OECD test guideline 202, and in compliance with GLP.

 

Following a preliminary range-finding test, 20 less than 24 hours old Daphnia magna(4 replicates of 5 animals) were exposed to aqueous solutions of Jasminlactone at nominal concentrations of 0 (control) 10, 18, 32, 56 and 100 mg/L in Elendt M4 Culture medium for 48 hours at a temperature of 20 to 21 °C under semi-static test conditions.

 

Analysis of the fresh and old test preparations showed the decline in measured concentrations; hence it was considered justifiable to base the results on the geometric mean measured test concentrations, which were determined to be were determined to be 6.3, 12, 23, 42 and 77 mg/L.

 

No sub-lethal effects of exposure were observed throughout the test. The highest concentration with no immobilisation was 42 mg/L, the second highest concentration tested, whereas 90% immobilisation was observed at concentration of 77 mg/L, the highest concentration tested.

 

It was concluded that the 48-hour EC50 in Daphnia Magna was 68 mg/L. The NOEC and LOEC were concluded to be 42 and 77 mg/L, respectively.