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

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 16 Dec. 2009 to 09 Jan. 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

This study was performed according to OECD Guideline 203 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 203 (Fish, Acute Toxicity Test)

Version / remarks:

17th July 1992

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples were taken for analysis from the freshly prepared solutions on the first and third day and also from these solutions after their replacement with freshly prepared solutions ("expired" solutions; after exposure approximately 24h).

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 0.300, 0.405, 0.548, 0.740 and 1.000 g of the test substance were added into the test water directly and then the respective bottles sealed. The test substance was dispensed in 10 L of water with the aid of propeller stirring at approximately 400 rpm for a period of 24h at 23 +/- 2°C and appeared clear and colorless after mixing. After 24h the stirring was stopped to give the test solution.
- Eluate: test water
- Control: yes
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebra fish (Brachydanio rerio)
- Strain: no data
- Source: Qianmin Fishery of Yuhong District in Shenyang
- Age at study initiation (mean and range, SD): juvenile
- Length at study initiation (length definition, mean, range and SD): 2-3 cm
- Weight at study initiation (mean and range, SD): no data
- Method of breeding: no data
- Feeding during test: no

ACCLIMATION
- Acclimation period: 12 days
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: no data
- Feeding frequency: daily until 24h before the test was started.
- Health during acclimation (any mortality observed): there were not any signs of disease and mortalities were less than 5% during this acclimatization period.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Remarks on exposure duration:

none

Post exposure observation period:

None

Hardness:

126 mg/L as CaCO3

Test temperature:

21.2-21.6°C

pH:

7.46-7.68

Dissolved oxygen:

7.35-8.48 mg/L
>60% of the air saturation value throughout the test

Salinity:

Not applicable

Conductivity:

No data

Nominal and measured concentrations:

- Nominal concentrations: 30.0, 40.5, 54.8, 74.0 and 100.0 mg/L
- Measured concentrations: 32.0, 41.4, 57.2, 77.8 and 111.7 mg/L in the freshly prepared solutions and 32.1, 36.9, 53.9, 74.2 and 101.2 mg/L in expired solutions. See table 6.1.1/1 in "Any other information on results incl. tables".

Details on test conditions:

TEST SYSTEM
- Test vessel: glass jars
- Type (delete if not applicable): no data
- Material, size, headspace, fill volume: diameter = 20 cm; high = 40 cm; 12.3-12.5 L full of water
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): renewal of the test solutions every 24h.
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: < 1.0 g fish/L water

TEST MEDIUM / WATER PARAMETERS
The water used for the aquatic was natural water treated with an activated carbon water filter then aerated for 24h. The physicochemical measurements of the water were: pH was in the range of 6.0 to 8.5, the water hardness was 126 mg/L as CaCO3.

OTHER TEST CONDITIONS
- Adjustment of pH: no data
- Photoperiod: 16h light photoperiod daily
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The fish were observed daily. The toxic signs and deaths were recorded at 3, 6, 24, 48, 72 and 96h after exposure. The criterion for death was no opercula movement during a 15 second period of observation.

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):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

53.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL: 43.7-65.9 mg/L

Duration:

96 h

Dose descriptor:

other: The highest concentration witout observed effects

Effect conc.:

32 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

See table 6.1.1/2 in "Any other information on results incl. tables".
During the 96h exposure period, the fish treater with the test concentration at 40.5 mg/L (geometric mean measured concentration is 39.1 mg/L), and higher concentrations showed visible toxic signs, e.g., lethargy, slowly swimming, and loss of equilibrium.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

The LC50 and 95% confidence limit values were calculated by the Probit method using the geometric mean measured concentration values.

Sublethal observations / clinical signs:

Table 6.1.1/2: Measured concentrations

Nominal concentrations (mg/L)	Measured concentrations (mg/L)				Mean fresh	Mean expired	Overall mean
	0-24h		72-96h
	Fresh	Expired	Fresh	Expired
Control 30.0 40.5 54.8 74.0 100.0	ND 30.4 41.9 57.2 81.6 111.7	ND 31.1 35.8 55.7 80.9 101.2	ND 33.6 40.9 57.2 74.2 -	ND 33.2 38.0 52.1 68.1 -	ND 32.0 41.4 57.2 77.8 111.7	ND 32.1 36.9 53.9 74.2 101.2	ND 32.0 39.1 55.5 76.0 106.3

Table 6.1.1/1: Cumulative mortality

Nominal concentrations (mg/L)	Geometric mean measured concentrations (mg/L)	Initial population	Time (h)	Cumulative mortality	Abnormalities
Control	-	7	3 6 24 48 72 96	0 0 0 0 0 0	No observed toxic signs
30.0	32.0	7	3 6 24 48 72 96	0 0 0 0 0 0	No observed toxic signs
40.5	39.1	7	3 6 24 48 72 96	0 0 0 1 1 2	Lethargy; slowly swimming; irreversible effect; visible damage
54.8	55.5	7	3 6 24 48 72 96	0 0 0 2 4 4	Lethargy; slowly swimming; irreversible effect; visible damage
74.0	76.0	7	3 6 24 48 72 96	0 0 0 4 6 6	Lethargy; slowly swimming; irreversible effect; visible damage
100.0	106.3	7	3 6 24 48 72 96	0 0 1 7 7 7	Lethargy; slowly swimming; irreversible effect; visible damage

Validity criteria fulfilled:

yes

Conclusions:

96h-LC50 = 53.7 mg/L (95% CL = 43.7 - 65.9 mg/L), based on geometric mean measured concentrations.

Executive summary:

This study was performed according to OECD Guideline 203 with GLP statement, to assess the 96h acute toxicity of the substance to zebra fish (Brachydanio rerio) under semi-static conditions.

Based on the results of a preliminary test, a definitive test was conducted with nominal concentrations of 30.0, 40.5, 54.8, 74.0 and 100.0 mg/L. A concurrent water control group was performed in parallel. The measured test concentrations were determined by GC system. The mean concentrations, calculated using the geometric means of the fresh and expired solutions were 32.0, 39.1, 55.5, 76.0 and 106.3 mg/L which is 97 -107% of the nominal concentrations, and the concentrations of expired solutions were 89 -101% of initial concentrations.

All validity criteria were fulfilled.

The results showed that the 96h-LC50 of the substance to Brachydanio rerio, based on geometric mean measured concentrations in the fresh and expired solutions, was 53.7 mg/L (Probit method) and the 95% confidence limit was 43.7 - 65.9 mg/L. The highest concentration without observed effect after 96 hours was 32.0 mg/L (geometric mean measured concentration).

Description of key information

OECD Guideline 203, GLP, key study, validity 1:
96h-LC50 = 53.7 mg/L (95% CL: 43.7 - 65.9 mg/L)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

53.7 mg/L

Additional information

One valid key study is available to assess the 96h acute toxicity of the substance to zebra fish (Brachydanio rerio). This study was performed according to OECD Guideline 203 with GLP statement, under semi-static conditions.

The definitive test was conducted with nominal concentrations of 30.0, 40.5, 54.8, 74.0 and 100.0 mg/L. A concurrent water control group was performed in parallel. The measured test concentrations were determined by GC system. The mean concentrations, calculated using the geometric means of the fresh and expired solutions were 32.0, 39.1, 55.5, 76.0 and 106.3 mg/L which is 97 -107% of the nominal concentrations, and the concentrations of expired solutions were 89 -101% of initial concentrations.

All validity criteria were fulfilled.

The results showed that the 96h-LC50 of the substance to Brachydanio rerio, based on geometric mean measured concentrations in the fresh and expired solutions, was 53.7 mg/L (Probit method) and the 95% confidence limit was 43.7 - 65.9 mg/L. The highest concentration without observed effect after 96 hours was 32.0 mg/L (geometric mean measured concentration).