7-Isopropyl-2H,4H-1,5-benzodioxepin-3-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:

From 14 Sep. 2009 to 29 Sep. 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

This study was performed according to OECD Guideline 202 and EU Method C.2 with GLP statement. All validity criteria were fulfilled and no deviations were observed. Therefore, this study is considered reliable without restriction.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

2008-11-12

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Duplicate samples were taken from each treatment at the start and end of each test medium renewal period. For sampling from the aged test media, the contents of the respective replicates were combined prior to sampling.
- Sample storage conditions before analysis: The samples were stored deep-frozen (at about -20°C) and protected from light until analysis was performed

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Dissolving 100 mg of test item (dosing amounts: 100.2 and 100.8 mg/L) in 1000 mL of test water using ultrasonic treatment for 15 minutes and intense stirring for 24 hours at room temperature in the dark. Adequate volumes of this test medium were diluted with test water to prepare the test media with the lower test item concentrations. The test media were prepared just before introduction of the daphnids.
- Eluate: test water
- Controls: yes, 1
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable
- Concentration of vehicle in test medium (stock solution and final test solution): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: clone 5
- Source: University of Sheffield / UK ; bred at Harlan Laboratories.
- Age at study initiation (mean and range, SD): 6-24 hours old
- Weight at study initiation (mean and range, SD): no data
- Length at study initiation (length definition, mean, range and SD): no data
- Valve height at study initiation, for shell deposition study (mean and range, SD): no data
- Method of breeding: under temperature and ligh conditions identical to those of the test.
- Feeding during test: no

ACCLIMATION
- Acclimation period: yes
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: Algal suspension of the green algae Scenedesmus subspicatus or a mixture of this algal suspension and a commercial fish diet.
- Feeding frequency: Three times a week
- Health during acclimation (any mortality observed): none

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

None

Test temperature:

21°C

pH:

7.8-8.1

Dissolved oxygen:

8.2-8.6 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

- Nominal concentrations: 4.6, 10, 22, 46 and 100 mg/L
- Measured concentrations: See table 6.1.3/1 in "Any other information on results incl. tables". At the start and end of both test medium renewal periods of 24 hours, the measured test item concentrations in the freshly prepared and aged test media of the analyzed nominal concentrations of 10-100 mg/L were between 99 and 111% of the nominal values. Thus, the correct dosing of the test substance was confirmed. Furthermore, it has been demonstrated that the test substance was stable during the test medium renewal periods of 24 hours under the conditions of the test, and the reported biological results are based on the nominal concentrations of the test substance.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beakers
- Type (delete if not applicable): covered with glass plates to reduce the loss of water by evaporation and to avoid the entry of dust into the solutions.
- Material, size, headspace, fill volume: filled with 50 mL of test medium
- Aeration: not aerated during the test.
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): medium renewal after 24 hours
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: 2 mL test medium/daphnid

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted test was according to ISO 6341.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16h light to 8h dark cycle with 30min transition period
- Light intensity: 520-680 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The immobility of the daphnids was determined by visual inspection after 24 and 48 hours of exposure. Those daphnids not able to swim within 15 seconds after gentle agitation of the test vessel were considered to be immobilized. In addition to immobility, any abnormal behavior or appearance was recorded.

TEST CONCENTRATIONS
- Range finding study: Yes
- Test concentrations: no data
- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

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:

other: The highest tested concentration witout observed effects

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Remarks on result:

other: due to abnormal appearance (all daphnids discolored and contourless)

Details on results:

See table 6.1.3/2 in "Any other information on results incl. tables".
- Behavioural abnormalities: After 48 hours of exposure, adverse effects (daphnids discolored and contourless) were observed in all daphnids at the test concentrations from 22 to 100 mg/L.
- Observations on body length and weight: no
- Other biological observations: none
- Mortality of control: none during the test
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration.
- Effect concentrations exceeding solubility of substance in test medium: none

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50/LC50: 0.71 mg/L (date of study: February 2009)

Reported statistics and error estimates:

None

Table 6.1.3/1: Analytical measurements

Sampling day / sample age (day/h)	Sample ID	Nominal concentration (mg/L)	Measured concentration (mg/L)			Sample preparation factor F	Determined average concentration (mg/L)	Recovery rate R (%)
			Sample 1	Sample 2	Average
0/0	D1 D5/6 D7/8 D9/10 D11/12	Control 10 22 46 100	<LOQ 10.6 23.7 47.9 101	- 10.7 22.6 47.4 99.7	n.a. 10.6 23.1 47.6 100	1 1 1 1 1	n.a. 10.6 23.1 47.6 100.2	n.a. 106 105 104 100
1/24	D13 D17/18 D19/20 D21/22 D23/24	Control 10 22 46 100	<LOQ 10.3 23.5 46.5 99.5	- 10.1 23.5 46.9 99.1	n.a. 10.2 23.5 46.7 99.3	1 1 1 1 1	n.a. 10.2 23.5 46.7 99.3	n.a. 102 107 102 99
1/0	D25 D29/30* D31/32 D33/34 D35/36*	Control 10 22 46 100	<LOQ 11.0 24.4 45.6 104	- - 24.4 47.4 -	n.a. 11.0 24.4 46.5 104	1 1 1 1 1	n.a. 11.0 24.4 46.5 104	n.a. 110 111 101 104
2/24	D37 D41/42 D43/44 D45/46 D47/48	Control 10 22 46 100	<LOQ 10.9 24.3 48.7 105	- 10.9 24.4 47.5 104	n.a. 10.9 24.4 48.1 105	1 1 1 1 1	n.a. 10.9 24.4 48.1 105	n.a. 109 111 104 105

* samples lost due to accident

Table 6.1.3/2: Effect of the test substance on the mobility of Daphnia magna

Nominal concentration (mg/L)	No. of daphnids tested	Immobilized daphnids after 24 hours		Immobilized daphnids after 48 hours
		No.	%	No.	%
Control 4.6 10 22 46 100	20 20 20 20 20 20	0 0 0 0 0 0	0 0 0 0 0 0	0 0 0 0* 0* 1*	0 0 0 0 0 5

* adverse effects observed (all tested daphnids discolored and contourless)

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 value was determined to be above 100 mg/L.

Executive summary:

This study was performed according to OECD Guideline 202 and EU Method C.2 with GLP statement, to assess the 48h acute toxicity of the test substance to Daphnia magna, under semi-static conditions.

The nominal test substance concentrations tested were 4.6, 10, 22, 46 and 100 mg/L. Additionally, a control group was tested in parallel.

At the start and end of both test medium renewal periods of 24 hours, the measured test item concentrations in the freshly prepared and aged test media of the analyzed nominal concentrations of 10-100 mg/L were between 99 and 111% of the nominal values. Thus, the correct dosing of the test substance was confirmed. Furthermore, it has been demonstrated that the test substance was stable during the test medium renewal periods of 24 hours under the conditions of the test, and the reported biological results are based on the nominal concentrations of the test substance.

After 48 hours of exposure, no immobilized test organisms were determined in the control and up to and including the test substance concentration of 46 mg/L. However, adverse effects (daphnids discolored and contourless) were observed in all daphnids at the test concentrations from 22 to 100 mg/L. This was considered to be a significant toxic effect. Moreover, at the highest test concentration of 100 mg/L, one test organism was found to be immobile. Thus, the highest tested concentration without observed effect after 48 hours was determined to be 10 mg/L and the 48h-EC50 value was determined to be above 100 mg/L.

No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration. At the beginning and end of the test medium renewal periods, the pH values of the test media were between 7.8 and 8.1. The dissolved oxygen concentrations in the test media and control were at least 8.2 mg/L, and water temperature was 21°C during the test.

All validity criteria were fulfilled.

Description of key information

OECD Guideline 202, EU Method C.2, GLP, key study, validity 1:
48h-EC50 > 100 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

One valid key study is available to assess the 48h-acute toxicity of the substance to Daphnia magna. This study was performed according to OECD Guideline 202 and EU Method C.2 with GLP statement, under semi-static conditions.

The nominal substance concentrations tested were 4.6, 10, 22, 46 and 100 mg/L. Additionally, a control group was tested in parallel.

At the start and end of both test medium renewal periods of 24 hours, the measured test item concentrations in the freshly prepared and aged test media of the analyzed nominal concentrations of 10-100 mg/L were between 99 and 111% of the nominal values. Thus, it has been demonstrated that the substance was stable during the test medium renewal periods of 24 hours under the conditions of the test, and the reported biological results are based on the nominal concentrations of the test substance. No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration. At the beginning and end of the test medium renewal periods, the pH values of the test media were between 7.8 and 8.1. The dissolved oxygen concentrations in the test media and control were at least 8.2 mg/L, and water temperature was 21°C during the test.

After 48 hours of exposure, no immobilised test organisms were determined in the control and up to and including the substance concentration of 46 mg/L. However, adverse effects (daphnids discolored and contourless) were observed in all daphnids at the test concentrations from 22 to 100 mg/L. This was considered to be a significant toxic effect. Moreover, at the highest test concentration of 100 mg/L, one test organism was found to be immobile. Thus, the highest tested concentration without observed effect after 48 hours was determined to be 10 mg/L and the 48h-EC50 value was determined to be above 100 mg/L.