4-Hydroxy-3,5-dimethylbenzonitrile

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:

2003-11-10 to 2004-02-26

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)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: duplicate samples from each test medium (test media and control) were taken just before the start of the test (with and withoud daphnids) and at the end of the test. For the 48-h stability samples, the contents of the respective replicates were combined.
- Sample storage conditions before analysis: All samples were deep-frozen (~-20°C) immediately after sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: the highest test concentration of nominal 100 mg/L was prepared by dissolving 150 mg test item completely in 1500 mL test water using ultrasonic treatment for 15 minutes and intense stirring for 1 hour at room temperature in the dark. The lower test item concentrations were prepared by diluting this test medium.
- Controls: yes
- Evidence of undissolved material (e.g. precipitate, surface film, etc): all test media were clear solutions throughout the entire test duration. The 2 highest test concentrations of 32 and 100 mg/L were brownish coloured by the test item.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Source: University of Sheffield/UK in 1992 (clone 5)
- Age at study initiation (mean and range, SD): 6-24 hours old and were not first brood progeny
- Method of breeding: the clone is bred in the RCC laboratories in reconstituted water of the quality identical to the water quality used in the tests (regarding pH, main ions, and total hardness) and under temerature and light conditions identical to those of the tests.

ACCLIMATION
- Acclimation period: since 1992, the clone is bred in reconstituted water of the quality identical to the water quality used in the test
- Acclimation conditions (same as test or not): same as the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg CaCO3/L

Test temperature:

21-22°C

pH:

7.6-7.8

Dissolved oxygen:

at least 8.2 mg/L.

Salinity:

not applicable

Nominal and measured concentrations:

Nominal test concentrations (mg/L): 1, 3.2, 10, 32, 100
Mean measured concentrations (mg/L): not analyzed, not analyzed, 10.5 (105% recovery), 31.5 (98% recovery), 106 (106% recovery)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers
- Type (delete if not applicable): covered with glass plates
- Aeration: the test water was aerated prior to the start of the study until oxygen saturation was reached
- Material, size, headspace, fill volume: 100 mL glass beakers filled with 50 mL test medium.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: lower than 1 Daphnia per 2 mL test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted test water
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4:1 (based on molarity)
- Culture medium different from test medium: no
- Intervals of water quality measurement: 2 days

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-hour light to 8-hour darkness photoperiod (with a 30 minute transition period)
- Light intensity: 520-710 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobility by visual control after 24 and 48h of exposure

TEST CONCENTRATIONS
- Spacing factor for test concentrations: x 3.2
- Range finding study: y
- Test concentrations: not reported
- Results used to determine the conditions for the definitive study: yes, according to the results of the range-finding test the concentration-effect relationship was rather flat and thus a large cocnentration range had to be tested.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

18 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 17.8-18.2

Details on results:

- Behavioural abnormalities: no
- Mortality of control: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no.
- The 24-h EC50 = 32 mg/L (95% CL 22.2-46.2 mg/L).
- The 48-h EC100 = 32 mg/L.
- The 48-h NOEC = 10.0 mg/L.

Results with reference substance (positive control):

- Results with reference substance valid? potassium dichromate is tested as a positive control at least once a year. no information about the result is reported.

Reported statistics and error estimates:

The EC50 values and their 95% confidence interval were calculated by Moving average Interpolation.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item T002251 to Daphnia magna was determined in a 48-hour static test according to the OECD guideline 202.
The 48-hour EC50 was 18.0 mg T002251/L. The results of the test can be considered reliable without restriction.

Description of key information

The study of Seyfried (2004), investigating the acute toxicity of T002251 in Daphnia magna according to OECD guideline 202, was considered as the key study for endpoint coverage. An EC50 of 18 mg/L was found after an exposure of 48 hours in a static test in freshwater. Based on the results it can be concluded that T002251 is harmful to aquatic invertebrates

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18 mg/L