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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
22 - 27 Mar, 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Physical state: viscous colorless liquid or solid at room temperature (22-23 °C)
- Source and lot/batch No.of test material: Lot 10115
- Expiration date of the lot/batch: 10 Jan 2019
- Purity: 95.6%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: frozen

FORM AS APPLIED IN THE TEST: solid. The test material did not liquefy after being brought to room temperature.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: All; sampled at test initiation, 24 hours, and at test termination. At 24 hours (renewal), both spent and new solutions were sampled.
- Sampling method: Samples were collected from middepth, placed in glass vials containing 2.00 mL of 0.5% formic acid in methanol, and processed immediately for analysis.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A primary stock solution was prepared by mixing a calculated amount of test substance in 4 L of dilution water at a nominal concentration of 100 mg formulation/L, the highest concentration tested. The stock solution concentration was not adjusted for the active ingredient of the test substance during preparation, and all concentrations are based on the test substance as received. The test substance was weighed onto two pieces of Teflon®, added to a 4 L WAF bottle containing 4 L of dilution water, and stirred for approximately four hours on a magnetic stir plate. A piece of neoprene was placed between the WAF bottle and the stir plate to minimize the potential of a temperature change in the stock solution. The stock solution appeared clear and colorless with white precipitate in the water column. The stock solution was allowed to settle briefly to allow the precipitate to settle out. The solution was drawn off through a spigot and tubing placed approximately 2-3 cm from the bottom of the aspirator bottle (mid-depth) and filtered through a 0.45 μm PTFE filter. Aliquots of the primary stock solution were proportionally diluted with dilution water to a final volume of 1 L to prepare four additional test solutions at nominal concentrations of 6.3, 13, 25 and 50 mg formulation/L. The solutions were stirred on a magnetic stir plate for approximately 15 minutes, and approximately 220 mL of solution was placed in each of four replicate test chambers per treatment group.
- Controls: dilution water
- Evidence of undissolved material: A white precipitate was present in the water column after preparation and stirring. the precipitate was allowed to settle out before the solution was drawn off, filted, and diluted to prepare test solutions.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Cladoceran; Water flea
- Source: Cultures maintained by the test laboratory with known history
- Age at study initiation: < 24 hours, from parental daphnids of more than two weeks old
- Culturing: Adult daphnids were cultured in water from the same source and at approximately the same temperature as used during the test. Adult daphnids in the cultures were held for at least 14 days prior to collection of the juveniles for testing. The adults showed no signs of disease or stress during the holding period. During the 14-day period preceding the test, water temperatures ranged from 19.6 to 20.8 °C. The pH of the water ranged from 8.1 to 8.4, and dissolved oxygen concentrations were ≥ 7.7 mg/L. Daphnids in the cultures were fed a mixture of yeast, cereal grass media and trout chow, supplemented with a vitamin stock solution and a suspension of the freshwater green algae, Raphidocelis subcapitata.. The adults were fed prior to test initiation, but neonates were not fed during the test.

FEEDING DURING TEST
- Food type: Not fed during test

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
144 mg CaCO3/L
Test temperature:
19.7 - 20.1 °C
pH:
8.0 - 8.4
Dissolved oxygen:
7.0 - 9.1 mg/L
Conductivity:
330 μS/cm
Nominal and measured concentrations:
Nominal: 6.3, 13, 25, 50 and 100 mg MTDID 10628/L
Measured: 0.41 (± 0.294), 0.99 (±0.502), 1.9 (±1.06), 4.4 (±1.86) and 9.1 (±4.02) mg formulation/L (geometric mean)
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL glass beaker, loosely covered wtih a plastic petri dish
- Fill volume: approximately 220 mL
- Depth: 7.0 cm
- Aeration: dilution water aerated prior to filling
- Renewal: Once at 24 hours
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 40-m deep well located at testing lab. Water was passed through a sand filter and pumped into a storage tank and aerated with spray nozzles. Water was filtered to 0.45 μm and UV-sterilized prior to testing. Periodic water analysis, Attachments 1 and 2.
- Total organic carbon: < 1 mg C/L
- Pesticides: all < LOQ
- Alkalinity: 186 mg CaCO3/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: most recent analysis on samples collected 20 Dec 2017

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h:8h with 30-min transitions
- Light intensity: 449 lux at surface of water of one representative chamber at test initiation

EFFECT PARAMETERS MEASURED : Mortality and immobilization at 24h and 48 h

RANGE-FINDING STUDY
- Test concentrations: 1.2, 3.7, 11, 33 and 100 mg formulation/L
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 9.1 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
act. ingr.
Basis for effect:
mobility
Remarks on result:
other: 9.1 mg/L was considered the maximum soluble concentration in test medium. Test conducted at a loading rate of 100 mg/L.
Details on results:
- Behavioural abnormalities: Lethargy (see Table 2)
- Mortality of control: None

Any other information on results incl. tables

Table 2. Cumulative percent mortality/immobility.

Nominal concentration (mg formulation/L)

Number Immobile / Observations1

Number Immobile / Observations1

Number Immobile / Observations1

Cumulative Percent Immobilized

 

~ 3 hours

24 hours

48 hours

 

Negative Control

0 / 20 AN

0 / 20 AN

0 / 20 AN

0

0.41

0 / 20 AN

0 / 20 AN

0 / 20 AN

0

0.99

0 / 20 AN

0 / 20 AN

0 / 20 AN

0

1.9

0 / 20 AN

0 / 20 AN

0 / 2 C; 18 AN

0

4.4

0 / 20 AN

0 / 20 AN

0 / 3 C; 21 AN

0

9.1

0 / 20 AN

0 / 20 AN

0 / 8 C; 12 AN

0

1 Observations:  AN = appears normal; C = lethargy

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Control immobilization was < 10% at the end of the test. The dissolved oxygen concentration was ≥ 3 mg/L in the control and test vessels throughout the test.
Conclusions:
There was no immobilization of Daphnia magna in a 48-hour test with 1,1'-isophthaloylbis(2-methylaziridine) at a nominal concentration of 100 mg/L (OECD 202). The measured geometric mean concentration of 1,1'-isophthaloylbis(2-methylaziridine) was 9.1 mg/L.
Executive summary:

The 48-hour EC50 of 1,1'-isophthaloylbis(2-methylaziridine) to Daphnia magna was examined in a semi-static test conducted according to OECD 202. Test solutions were prepared at nominal concentrations of 6.3, 13, 25, 50 and 100 mg formulation/L. The associated geometric mean measured concentrations were 0.41, 0.99, 1.9, 4.4, and 9.1 mg formulation/L. No immobilization of the daphnids was observed by 48 hours. The 48-hour EC50 is > 9.1 mg/L based on the measured concentration and > 100 mg/L based on the nominal concentration.

The test was conducted according to internationally accepted test guidelines and was GLP compliant. It is reliable without restriction and suitable for Risk Assessment, Classification and Labeling, and PBT Analysis.