Reaction products of 2,4-bis(2-chlorophenyl)-5-(3,4-dimethoxy phenyl)-1H-imidazole and 2-(2-chlorophenyl)-4,5-diphenyl-1H-imidazole

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Details on test material:

- Purity: 100% as a reaction product

Test solutions

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION:
The limit test concentration was prepared as a stock solution of the test substance in Haskell well water (HWW). The 120 mg/L stock solution was prepared by adding approximately 0.12 g of test material to HWW in a 2-L glass beaker (final volume 1 L), stirring for approximately 5 minutes, sonicating for approximately 160 minutes, and stirring again for approximately 12 minutes. The 120 mg/L test substance solution was yellow and cloudy with undissolved test substance and a surface film present.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM:
- Strain: Daphnia magna
- Age at study initiation: < 24 hours
- Feeding during test: None

CULTURE DETAILS:
Daphnia magna were reared in 1000 mL glass beakers (10 per beaker at start of culture) which contained 1000 mL of aerated, filtered well water held at 20 ± 2 °C. Daphnids were fed on a daily basis with 3 mL/L of a yeast, cereal leaves and trout chow (YCT) mixture and the green alga, Pseudokirchneriella subcapitata, at a rate of approximately 62500 cells/mL of culture media. The YCT mixture was standardized to 1700-2100 mg/L solids. The combination of YCT and alga is equivalent to 0.1-0.2 mg total organic carbon per daphnid per day. Neonates used in this test were less than 24 hours old and were collected from the 4th brood of 14-day old parent daphnids. Sickness, injury, and abnormalities were not seen and ephippia were not being produced by the parent daphnids. No adult immobility was seen in the cultures used for testing during the 48 hour pretest period. Daphnia magna were identified by labels on the culture beakers and test chambers.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

100 - 140 mg/L as CaCO3

Test temperature:

19.3 - 20.6°C

pH:

7.9 - 8.2

Dissolved oxygen:

7.1 - 8.8 mg/L

Nominal and measured concentrations:

Nominal concentrations: 120 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: covered glass beakers
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

LIGHT CONDITIONS
- Photoperiod: 16 hours light (approximately 206 - 232 Lux) and 8 hours darkness
Included 30 minutes of transitional light (12 - 24 Lux) preceding and following the 16-hour light interval

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Observations of test organisms were made daily. The criterion for the effect (immobility) was a lack of reaction to application of a gentle stimulus.

TEST CONCENTRATIONS
- Range finding study: One nominal concentration and a dilution water control were used in this study. The nominal, limit test concentration of 120 mg/L was chosen for the definitive limit test based on the results of a preliminary range finding study.

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: highest concentration tested

Details on results:

- Behavioural abnormalities: No immobility or sublethal effects were seen.

- Mortality of control: No immobility or sublethal effects were seen in the dilution water control.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

48-hour EC50 > 120 mg/L

Executive summary:

The acute toxicity of the test substance to unfed Daphnia magna neonates, less than 24 hours old at test start, was determined in an unaerated, static, acute, 48 hour limit test. The test was conducted in accordance with the OECD Guideline for the Testing of Chemicals: 202. The study was conducted with a single 120 mg/L nominal concentration and a dilution water control at a mean temperature of 20.0°C (range of 19.3-20.6°C). Four replicates with 5 daphnids per replicate were used per limit test concentration and dilution water control.

No immobility or sublethal effects were observed in daphnids in the dilution water control or in the 120 mg/L nominal test concentration at the end of the 48 hour limit test. The 48 hour EC₅₀, based on the nominal concentration and immobility, was greater than 120 mg/L.