NITTA

Short-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26-28 September 2017

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Test material form:

liquid: viscous

Details on test material:

- Appearance: brown viscous liquid
- Storage conditions: room temperature in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Whole test vessels were analysed for both dissolved and undissolved test substance using a high-performance liquid chromatography mass spectrometry method.
At the start of the test and at 24 hours, additional sacrificial test vessels were used for sampling and at the end of the test one replicate of the dilution water control, solvent control and each test concentration was sampled. The method of whole sample analysis was used due to the low solubility of the compound.
Temperature, pH and dissolved oxygen concentrations were measured at 0, 24 and 48 hours.

Test solutions

Vehicle:

yes

Details on test solutions:

A primary stock concentrate of NITTA, with a nominal concentration of 10 g/L, was prepared by adding a nominal 0.1 g of test substance to 10 mL of the solvent dimethylformamide (DMF). The resultant stock was observed to be clear and a pale-yellow colour and was used to prepare the test solutions.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The test organism was the freshwater crustacean, Daphnia magna, obtained from continuous laboratory cultures held at Scymaris.
The stock cultures of D. magna were maintained in a reconstituted water medium, the same as the test dilution water, at a temperature of 20 ± 2°C. The cultures were maintained in 2 L glass vessels with a working volume of 1.6 L. A photoperiod of 16 hours’ light:8 hours dark, with 20-minute transition periods was provided.
The D. magna cultures were fed on a mixed algae diet of Chlorella vulgaris, strain CCAP 211/12 and Pseudokirchneriella subcapitata, strain CCAP 278/4. The D. magna cultures were fed daily ad libitum depending on age and density of the culture. Culture conditions were such that the D. magna reproduction was by diploid parthenogenesis.
D. magna <24 hours old, obtained from a single culture vessel, were used for testing. The parent animals were 21 ± 1 days old and had been maintained with a twice weekly renewal of reconstituted water medium since birth. The test organisms and the culture from which they were obtained showed no evidence of disease before the test period.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

209.7 mg/L CaCO3

Test temperature:

19.8 - 20.4 °C

pH:

Ranged from 7.60 to 8.13.

Dissolved oxygen:

Ranged from 8.71 to 9.24 mg/L

Nominal and measured concentrations:

0.0625, 0.125, 0.25, 0.5, 1.0 mg/L (nominal concentration)
0.049, 0.11, 0.22, 0.44, 0.91 mg/L (mean measured concentration, based on whole sample extraction, i.e. dissolved and undissolved)

Details on test conditions:

Four replicates per test concentration.
Twenty daphnia per treatment.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.91 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Based on immobility compared to the control (p <0.05) the 48 hour No Observed Effect Concentration (NOEC) was determined to be 1.0 mg/L and the Lowest Observed Effect Concentration (LOEC) was >1.0 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

As no immobility or other signs of stress were observed in the control and dissolved oxygen concentration remained at greater than 3 mg/L this test has satisfied all validity criteria.

Conclusions:

The 48-hour EC50 for NITTA was reported as >1.0 mg/L nominal (>0.91 mg/L measured).

Executive summary:

Data are available from a GLP compliant study following OECD Guideline 202. A solvent (dimethylformamide) was used in this study to assist in dosing the test compound in test media. The test was carried out at 5 concentrations, plus control and solvent control, run in four replicates. Results were reported based on measured and nominal NITTA concentrations (Scymaris 2017). This study is considered to be suitable for use as a key study for this endpoint. The 48 hour EC50 for NITTA was reported as >1.0 mg/L nominal (>0.91 mg/L measured).