1,4-naphthoquinone

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

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

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Test solution samples were taken at the beginning and end of each renewal period i.e. one set consists of a new sample of test solution at the time of preparation and an old sample of the same test solution immediately prior to renewal or at the end of exposure.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Two stock solutions were initially prepared. Firstly at 100 mg/L. This was stirred for 48 hours and then filtered. The resulting solution was then used to prepare another stock solution at 0.2 mg/L which was further diluted to prepare the remainder of substance concentrations.
- Controls: Dilution water
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): None observed in final test solutions.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: National institute for environment studies, Japan
- Age of parental stock (mean and range, SD): At least 2 weeks
- Feeding during test: No

ACCLIMATION
- Acclimation period: At least 2 weeks
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: Chlorella Vulgaris (6 mg C (organic carbon)/2 L per day
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): 20% of less during the two week period before commencement

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:Juvenilles less than 24 hours old were used for the test

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

242 mg CaCO3/L

Test temperature:

20 +/- 1°C in test groups

pH:

6 to 9 of which the variation was in the range of 1.5

Dissolved oxygen:

3 mg/L or greater in test groups

Salinity:

Not detailed

Conductivity:

Not detailed

Nominal and measured concentrations:

Nominal: 0.01, 0.021, 0.045, 0.095 and 0.2 mg/L
Measured (mean time weighted average): 0.00364, 0.0088, 0.0197, 0.0441 and 0.0833 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beaker
- Type (delete if not applicable): open (covered with Teflon sheet to limit evaporation)
- Material, size, headspace, fill volume: 100 mL
- Aeration: No
- 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: Standard Elendt M4 medium as per OECD guidelines (including relevant vitamins)

OTHER TEST CONDITIONS
- Adjustment of pH: None
- Photoperiod: 16 hour light/8 hour dark
- Light intensity: 800 Lux or less

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilisation at 24 and 48 hours.

RANGE-FINDING STUDY
- Test concentrations: 0.0001, 0.001, 0.01 and 0.1 mg/L.
- Results used to determine the conditions for the definitive study: 90% immobilisation was observed after 48 hours of exposure. This information was used to select the test concentrations in the main phase of the study.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.026 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limits: 0.0197 to 0.0441 mg/L

Details on results:

- Behavioural abnormalities:
- Observations on body length and weight: Not assessed
- Other biological observations: None observed
- Mortality of control: 0% at the end of exposure
- Other adverse effects control: None observed
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No precipitation observed
- Immobility: 0, 0, 15, 100 and 100 % immobilisation at 0.01, 0.021, 0.045, 0.095 and 0.2 mg/L respectively.

Results with reference substance (positive control):

- Results with reference substance valid? Yes (EC50 within historical laboratory background ranges)
- Relevant effect levels: EC50
- Limit test: No
- Dose-response test: Yes
- EC50: 0.49 mg/L

Reported statistics and error estimates:

EC50 value calculated using a binominal method.

Validity criteria fulfilled:

yes

Remarks:

No mortality was observed in the controls and DO was maintained throughout the study

Conclusions:

An OECD guideline, GLP study assessing the acute toxicity of the substance to aquatic invertebrates provided a 48 hour EC50 value of 0.0261 mg/L.

Description of key information

A reliable OECD guideline and GLP study is available assessing the acute toxicity of the substance to aquatic invertebrates. No data is available assessing the toxicity of the substance to marine invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.026 mg/L