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

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

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)

Version / remarks:

Adopted: 13 April 2004

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Four-day-old daphnids were obtained from the National Institute of Agricultural Science & Tech. (166, Nongsaengmyeong-ro, Iseo-myeon, Wanju-gun, Jeollabuk-do, Republic of Korea) on Apr. 18, 2017.
- Feeding during test: no

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
Young daphnids of less than 24 h old were obtained from the mature daphnids of more than 14 days old and giving birth to over three generations and were transferred to new culture beakers and bred for 28 days. The culture beakers were maintained at 20±1°C in a water bath on a cycle of 16 h of continuous artificial light and 8 h of continuous darkness. Daphnids were fed daily with a suspension of Chlorella sp. (0.1–0.2 mgC/daphnid/day).
During the culture period, culture beakers holding daphnids were observed for general symptoms (behavior, antennae movement and appearance), neonate production and ephippia once daily except on Sunday.
Young daphnids of less than 24 h old obtained from the mature daphnids of more than 14 days old and giving birth to over three generations were used for this study.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

range-finding study: 20.1-20.3 °C (measured)
main study: 20.2-20.4 °C (measured)

pH:

range-finding study: 7.94 - 7.99 (measured)
main study: 7.61-7.83 (measured)

Dissolved oxygen:

range-finding study: 8.82 - 9.24 mg/l (measured)
main study: 8.17 - 8.74 mg/l (measured)

Nominal and measured concentrations:

Range-finding study
Nominal: 0, 0.1, 10, 20, 100 mg/l
Main study
Nominal: 0, 100 mg/l
Measured (corrected for recovery) at 0 h: N.D., 84.59 mg/l
Measured (corrected for recovery) at 48 h: N.D., 99.96 mg/l

Details on test conditions:

TEST SYSTEM
- fill volume: 100 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Photoperiod: 16 h light / 8 h darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Daphnids were observed for general symptoms (behavior, antennae movement and appearance) and immobilisation at 24 and 48 h

RANGE-FINDING STUDY
- Results used to determine the conditions for the definitive study: In the range finding study, all the daphnids did not show immobilisation or abnormal symptoms at all test concentrations (0.1, 1, 10, 20 and 100 mg/L). Therefore, a limit test was performed at 100 mg/L.

Reference substance (positive control):

yes

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

Results with reference substance (positive control):

- Results with reference substance valid? Yes. The test with the reference substance was not concurrent but was done every 6 months. The recent results (EC50) of the positive control study were 1.72 and 1.19 mg/L for 24 and 48 h respectively, which were within the permissible range of historical data (mean±2SD: 1.28–2.04 mg/L (24 h), 0.95–1.31 mg/L (48 h)) of Biotoxtech Co., Ltd. Exposure conditions of the positive control study were identical to the conditions of the main study.

Validity criteria fulfilled:

yes

Remarks:

Control: the % immobilisation was < 10% and no abnormal signs or behaviors such as discoloration and trapping at the surface of water were evident. Control and treatment: the dissolved oxygen concentrations were ≥ 3 mg/L at the end of exposure.

Executive summary:

This study was designed to assess the acute toxicity and to determine the median effect concentration (EC50) of the test substance, 2,2’-[ethylenebis(oxymethylene)]bisoxirane on the immobilisation of Daphnia magna during an exposure period of 48 h under static test conditions. Based on the result of the range finding study, the definitive study was conducted and the treatment level was selected at 100 mg/L and a control group was prepared for this study.

During the exposure period, the percent immobilisation in the control group was less than 10%. No abnormal signs or behaviors such as discoloration and trapping of Daphnia magna at the surface of water were evident in the control group. In addition, the dissolved oxygen concentrations in the control group and treatment group were 3 mg/L or more at the end of exposure. Therefore, the results were considered to be acceptable.

As a result of the concentration analysis of the test substance, the measured values in the 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.

No immobilisation or abnormal signs were evident in the 100 mg/l treatment group.