2,2'-[ethylenebis(oxymethylene)]bisoxirane

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Source: National Institute of Environmental Research (42, Hwangyeong-ro, Seo-gu, Incheon, Republic of Korea)
- Length at study initiation: range-finding study: 2.26–2.58 cm; main study: 2.10–2.47 cm
- Weight at study initiation: range-finding study: 0.218–0.268 g; main study: 0.219–0.266 g
- Method of breeding: Upon receipt, suitable male and female fish, at a ratio of 3 to 2 without any visible abnormalities and of similar size, were selected and placed in 50 L of breeding water. Approximately 25 fish (±10%) were bred. Eggs were harvested in breeding chambers and placed in hatching chambers. After hatching, the fry were placed in breeding chambers maintained at 23±1°C and bred. Approximately 30% of holding water was replaced once a week. The holding room was artificially illuminated; a 16-hour artificial light and 8-hour dark cycle. Fish were fed Brine shrimp (Ocean Star International, Inc., U.S.A.) in the morning and Top Meal (Jaeilfeed Co., Republic of Korea), at an amount corresponding to approximately 3% of their body weight, in the afternoon daily except from Saturday afternoon to Sunday, when they were fasted.

ACCLIMATION
- Acclimation period: 10 days
- Acclimation conditions: same as test
- Type and amount of food during acclimation: Brine shrimp (Ocean Star International, Inc., U.S.A.) in the morning and Top meal (Jaeilfeed Co., Republic of Korea) in the afternoon, at an amount of approximately 3% of their body weight, once daily except from Saturday afternoon to Sunday when they were fasted.
- Health during acclimation (any mortality observed): During 7 days prior to exposure, the mortality of a batch of fish was < 5% of the population.

FEEDING DURING TEST
- Frequency: Fish were not fed from 24 hours prior to exposure until the end of exposure.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

range-finding study: 22.3 - 22.8 °C
main study: 22.2 - 22.8 °C

pH:

range-finding study: 7.58 - 7.74
main study: 7.66 - 7.80

Dissolved oxygen:

range-finding study: 8.54 - 8.92
main study: 8.14 - 8.45

Nominal and measured concentrations:

Range-finding study
Nominal: 0, 0.1, 1, 10, 20 and 100 mg/l (nominal)
Main study
Nominal: 0, 30.1, 40.6, 54.9, 74.1 and 100 mg/l
Measured (corrected for recovery) at 0 h: N.D, 31.51, 42.39, 57.95, 75.09, 97.71 mg/l
Measured (corrected for recovery) at 96 h: N.D, 32.49, 41.27, 52.80, 70.90, 95.36 mg/l

Reference substance (positive control):

yes

Remarks:

but not concurrent

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

63.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Results with reference substance (positive control):

- Results with reference substance valid? yes
Oryzias latipes were exposed once every 6 months to the reference substance (Copper (II) Sulfate) for 96 h. The recent result (LC50) of the positive control study was 0.74 mg/L, which was within the permissible range of historical data (mean±2SD: 0.26–0.70 mg/L) of Biotoxtech Co., Ltd. Exposure conditions of the positive control study were identical to the conditions of the definitive study.

Validity criteria fulfilled:

yes

Remarks:

The mortality in the control group was 0%. The dissolved oxygen concentrations in the treatment groups and control group were maintained at more than 60% of the air-saturation values.

Executive summary:

This study was designed to assess the acute toxicity and to determine the median lethal concentration (LC50) of the test substance, 2,2’-[ethylenebis(oxymethylene)]bisoxirane, in Ricefish (Oryzias latipes) during an exposure period of 96 hours under static test conditions. Based on the result of the range finding study, the definitive study was conducted and the treatment levels were selected at 30.1, 40.6, 54.9, 74.1 and 100 mg/L, and a control group was prepared for this study.

During the exposure period, the mortality in the control group was 0%. The dissolved oxygen concentrations in the treatment groups and control group were maintained at more than 60% of the air-saturation values. Therefore, the results were considered to be acceptable.

As a result of the concentration analysis of the test substance, the measured values in the 30.1, 40.6, 54.9, 74.1 and 100 mg/L treatment groups during the exposure period were from 80 to 120% when compared to the nominal concentrations. Therefore, all test results were determined based on the nominal concentrations.

Based on the result of this study, the LC50 values obtained under the test conditions with the test substance, 2,2’-[ethylenebis(oxymethylene)]bisoxirane, were determined to be >100 mg/L at 24 and 48 h after exposure, 73.4 mg/L (95% confidence limits: 64.6–83.6 mg/L) at 72 h after exposure and 63.8 mg/L (95% confidence limits: 56.3–72.2 mg/L) (measured concentration) at 96 h after exposure.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

63.8 mg/L