Acetylcysteine

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:

2018-04-10 to 2018-06-09

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 the freshly prepared test medium of the test concentration and the control were taken at the start of the test. For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentration during the test period, duplicate samples from the test medium of the test concentration and the control were collected at the end of the test (after 48 hours).
- Sample storage conditions before analysis: All samples were stored in a freezer (< - 20 °C), protected from light, until analysis was performed. Afterwards the samples were again stored deep frozen (< -20 °C) and will be kept stored up to the date of the final report.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: 100 mg/L was prepared by dissolving 40 mg test item into 400 mL test water by intense stirring for 10 minutes.
- Controls: test water only
- Evidence of undissolved material: no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna (Straus), clone 5
- Source: in-house laboratory culture
- Age of parental stock: 1.75 - 19.75 hours
- Feeding during test: no
- Breeding conditions: bred under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in Elendt M4 medium. The test organisms were not first brood progeny. Daphnids in stock culture were fed at least on all working days with green algae (Desmodesmus subspicatus)

ACCLIMATION: was not necessary, since the test was performed in the same medium as the culturing

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

No

Hardness:

2.5 mmol/L (= 250 mg/L) as CaCO3

Test temperature:

19.9 - 20.4 °C

pH:

6.3 to 8.0 at test start; 7.6 to 7.8 at test end

Dissolved oxygen:

9.2 mg/L at test start; 8.8 mg/L at test end

Salinity:

Not applicable

Conductivity:

Not available

Nominal and measured concentrations:

Nominal: 100 mg/L
Measured: 100% of nominal (100 mg/L)

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
- Material, size, fill volume, lid: glass, 100 mL nominal, filled with approximately 60 mL test medium, covered with lid
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration: 4
- No. of vessels per control: 4

TEST MEDIUM / WATER PARAMETERS
- Preparation of dilution water: tes media were prepared with deionised water

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light : 8 h dark
- Light intensity: 670 to 820 lux

EFFECT PARAMETERS MEASURED: mobility after 24 and 48 hours


RANGE-FINDING STUDY (non-GLP)
- Test concentrations: 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium hydrogen phthalate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Behavioural abnormalities: no
- Observations on body length and weight: no
- Other biological observations: no
- Mortality of control: no
- Other adverse effects control: no
- Abnormal responses: no
- Any observations that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: EC50
- Limit test: no
- Dose-response test: yes
- EC50 (48 hours): 1.02 mg/L

Reported statistics and error estimates:

NOEC and LOEC were determined directly from the raw data.

Validity criteria fulfilled:

yes

Conclusions:

In a Immobilisation Test with Daphnia magna according to OECD TG 202 and EU Method C.2, the 48-hour EC50 of the test item was determined to be >100 mg/L.

Executive summary:

The toxic effect of the test item to Daphnia magna was assessed in a static limit test according to OECD TG 202, EU Method C.2 and GLP principles. Young daphnids were exposed for 48 hours to the test item concentration of 100 mg/L (5 animals per vessel, 4 replicates). In parallel a negative control (test water only) was performed (5 animals per vessel, 4 replicates). The suitability of the test item was confirmed by a positive control with the reference compound potassium hydrogen phthalate. The test item concentration was verified by analysis of Total Organic Carbon to be 100% of the nominal concentration. Therefore, biological results are based on nominal test item concentration.The 48-hour EC50 was determined to be >100 mg/L. The 48-hour NOEC was determined to be at least 100 mg test item/L. The NOEC might even be higher than this concentration, but concentrations in excess of nominal 100 mg test item/L have not been tested according to the recommendations of the test guidelines. The 48-hour LOEC was higher than 100 mg test item/L. These values could not be quantified due to the absence of toxicity of the test item up to nominal 100 mg/L. All validity criteria of the guidelines were fulfilled.

Description of key information

In an Acute Immobilisation Test with Daphnia magna according to OECD TG 202 and EU Method C.2, the 48-hour EC50 of the test item was determined to be >100 mg/L (reference 6.1.3 -1).

Additional information

The toxic effect of the test item to Daphnia magna was assessed in a static limit test according to OECD TG 202, EU Method C.2 and GLP principles. Young daphnids were exposed for 48 hours to the limit test item concentration of 100 mg/L (5 animals per vessel, 4 replicates). In parallel a negative control (test water only) was performed (5 animals per vessel, 4 replicates). The suitability of the test item was confirmed by a positive control with the reference compound potassium hydrogen phthalate. The test item concentration was verified by analysis of Total Organic Carbon to be 100% of the nominal concentration. Therefore, biological results are based on nominal test item concentration.The 48-hour EC50 was determined to be >100 mg/L. The 48-hour NOEC was found to be at least 100 mg test item/L. The NOEC might even be higher than this concentration, but concentrations in excess of nominal 100 mg test item/L have not been tested according to the recommendations of the test guidelines. The 48-hour LOEC was higher than 100 mg test item/L. These values could not be quantified due to the absence of toxicity of the test item up to nominal 100 mg/L. All validity criteria of the guidelines were fulfilled (reference 6.1.3 -1).