5-chloro-1,3-dihydro-1-(4-piperidinyl)-2H-benzimidazol-2-one

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

Study period:

2015-08-14 to 2015-09-02

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: A14JB3414
- Expiration date of the lot/batch: 2015-10-01 (retest date)
- Purity test date: 2014-12-22 (certificate of analysis release date)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature
- Stability under test conditions: not indicated
- Solubility and stability of the test substance in the solvent/vehicle: 0.5 g/L in water

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Samples for possible analysis were taken from all test concentrations and the control at t=0 and t=48h. 1.7 mL of volume was taken from the approximate centre of the test vessels. At the end of the exposure period, the replicates were pooled at each concentration before sampling.
- Sample storage conditions before analysis: The samples were stored in a freezer. Additionally, reserve samples of 1.7 mL were taken for possible analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of test solutions started with a loading rate of 100 mg/L applying 2 days of magnetic stirring to reach the maximum solubility of the test item in the test medium. The resulting aqueous mixture was filtered through a preconditioned 0.45 µm membrane filter (Whatman; RC55) where after the saturated solution (SS) was used as the highest test concentration. The lower test concentrations were prepared by subsequent dilutions of the SS in test medium.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): final test solutions were clear and colourless

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water-flea
- Source: in-house laboratory culture with a known history
- Age at study initiation (mean and range, SD): < 24 h (from parental daphnids of more than 2 weeks old, maximum age 4 weeks)
- Method of breeding: 250 newborn daphnids (i.e. less than 3 days old) are placed into 5 liters of medium in an all-glass culture vessel. Medium is M7. After 7 days of cultivation half of the medium is renewed twice a week.
- Feeding during cultivation: fresh water algae, daily
- Feeding during test: no

ACCLIMATION
- Acclimation period: not relevant

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/L as CaCO3

Test temperature:

19-21°C

pH:

At t=0h: 7.8 - 8.4
At t=48h: 8.0 - 8.2

Dissolved oxygen:

At t=0h: 8.5 - 8.7
At t=48h: 8.1 - 8.2

Salinity:

not relevant

Nominal and measured concentrations:

Range finder:
Nominal concentrations: 10 and 100% of SS (1% of SS not analysed)
Measured concentrations (mg/L) at t=0h: 10.5, 103
Measured concentrations (mg/L) at t=48h: 10.3, 103

Final test:
Nominal concentrations: 10, 18, 32, 56, 100% of SS
Measured concentrations (mg/L) at t=0h: 10.3, 18.9, 32.6, 60.3, 107
Measured concentrations (mg/L) at t=48h: 10.5, 18.8, 32.7, 61.1, 107

Actual concentrations were at the level of 102-108% of nominal and remained stable during the exposure (100-102% of initial at the end of the test).

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: 100 mL, glass beaker filled with 80 mL
- Aeration: not during the test
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Test medium: adjusted ISO medium

OTHER TEST CONDITIONS
- Photoperiod: 16h light daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobility was defined as those organisms which are not able to swim within 15 seconds after gentle agitation of the test container and was monitored after 24 and 48 hours of continuous treatment with the test substance.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study
- Test concentrations: 1, 10 and 100% of a SS prepared at a loading rate of 100 mg/L (setup: combined range finder/limit test)
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

33 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% C.L.: 24-41 mg/L

Details on results:

- Mortality of control: none
- Other adverse effects control: no
- Abnormal responses: none

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Mortality: no
- EC50/LC50: 48-h EC50 = 0.39 mg/L. The sensitivity of the daphnids was within the range determined with the historical data collected at Charles River Laboratories Den Bosch.

Reported statistics and error estimates:

The EC50 values were calculated from the Weibull analysis of the percentage of affected daphnids and the logarithms of the corresponding test item concentrations using the maximum likelihood estimation method.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of T000990 to Daphnia magna was determined in a 48 hour static test according to OECD guideline 202. Based on nominal concentrations, the 48-h EC50 was 33 mg/L (95% confidence interval between 24 and 41 mg/L). The results of the test can be considered reliable without restriction.

Description of key information

The study of Tobor-Kaplon (2016), investigating the acute toxicity of T000990 in Daphnia magna according to OECD guideline 202, was considered as the key study for endpoint coverage. An EC50 of 33 mg/L (based on analytically confirmed nominal test concentrations) was found after an exposure of 48 hours in a static test in freshwater. Based on the results it can be concluded that T000990 is harmful to aquatic invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

33 mg/L