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Ecotoxicological information

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
Remarks:
The study was conducted according to guideline in effect at time of study conduct.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Purity: 99.7%

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: Samples were collected from each replicate test vessel after 0 and 48 hours (final samples were collected before 48 hours if complete mortality occurred in a test vessel)
- Sampling method: GC equipped with flame ionization detector
- Sample storage conditions before analysis: Not reported

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION: A 1000 mg/L stock solution was formulated by combining test substance and dilution water in a glass jar. The test substance was added below the water surface with a syringe. The jar was filled to capacity to eliminate head space and tightly capped. The stock solutions were placed on an orbital shaker adjusted to approximately 150 rpm and incubated at approximately 30°C for 24 hours. Solutions were then incubated at 20±1°C for 48 hours without shaking. Dilution water used to formulate test media and for the control was shaken and incubated in the same manner as the stock solutions. Following the 72-hour incubation, the stock solution was carefully removed from the glass jar, and an effort was made to avoid collecting insoluble test substance. The stock solution was used immediately to formulate test media. The dilution water was carbon-filtered, deionized water. The dilution water was stored in polyethylene tanks, where it was aerated and recirculated through particle filters, activated carbon, and an ultraviolet sterilizer.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM:
- Strain: Daphnia magna
- Age at study initiation: juvenile
- Feeding during test: None

ACCLIMATION
- Acclimation period: Not reported

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
hardness ranged from 160-180 mg/L
Test temperature:
Temperature ranged from 19.3-20.6°C
pH:
pH ranged from 7.6-8.6
Dissolved oxygen:
Dissolved oxygen ranged from 8.2-9.3 mg/L
Nominal and measured concentrations:
Nominal concentrations: 0, 8.1, 14, 23, 38, 64, and 106 mg/L
Measured concentrations (initial): 0, 8.59, 13.9, 21.8, 37.1, 60.4, and 98.2 mg/L
Measured concentrations (final): 0, 4.34, 7.02, 10.2, 18.4, 27.7, and 47.9 mg/L (samples from nominal 38, 64, and 106 mg/L were collected at 24 hours)
Details on test conditions:
TEST SYSTEM
- Test vessel: 40 mL (nominal) glass vials containing 42 mL of test solution; because of the volatile nature of the test substance, test vessels were sealed and were not opened during the exposure period unless complete mortality occurred.
- No. of organisms per vessel: 4
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Conductivity: Conductivity ranged from 570-590 µmhos/cm

OTHER TEST CONDITIONS
- Adjustment of pH: Not reported
- Photoperiod: 16 hour light and 8 hour dark, with a 15-minute transition period between dark and light
- Light intensity: 85 foot-candles

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mortality and immobilization at 0, 24, and 48 hours

TEST CONCENTRATIONS
- Range finding study: A method trial study was conducted under static conditions using a stock solution prepared in dimethylformamide with control and 5 test concentrations (0.0016, 0.016, 0.16, 1.6, and 16 mg/L). At the end of 48 hours, there was 100% survival at all concentrations. A second method trial study was conducted under static conditions using a stock solution prepared in dilution water with a control and 2 test concentrations (160 and 1600 mg/L). At the end of 48 hours, there was 100% survival in the control, 65% survival at 160 mg/L, and 25% survival at 1600 mg/L. Daphnids were seen stuck to insoluble beads of test substance in test vessels. A third method trial study was conducted under static conditions using a stock solution prepared in dilution water and stirred for 24 hours with a control and 1 test substance (1600 mg/L). At the end of 48 hours, there was 100% survival in the control and 1600 mg/L. A rangefinding test was conducted under static conditions with a solvent control and 2 test concentrations (8 and 80 mg/L) prepared using a stock solution prepared in dimethylformamide. At the end of 48 hours, there was 100% survival in all test vessels. A second range-finding test was conducted under static conditions with a control and 3 test concentrations (0.93, 9.5, and 110 mg/L). At the end of 48 hours there was 0% survival at 110 mg/L and 100% survival at all other concentrations.

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
10.6 mg/L
Nominal / measured:
meas. (initial)
Basis for effect:
mobility
Remarks on result:
other: 95% confidence interval of 8.59-13.9 mg/L
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
11.7 mg/L
Nominal / measured:
meas. (initial)
Basis for effect:
mortality
Remarks on result:
other: 95% confidence interval of 8.59-13.9 mg/L
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
< 8.59 mg/L
Nominal / measured:
meas. (initial)
Details on results:
- Behavioural abnormalities: Immobilization was observed at 24 hours (21.8 mg/L) and 48 hours (≥8.59 mg/L)
- Mortality of control: 0%
Reported statistics and error estimates:
Results of the toxicity test were analyzed using standard statistical techniques. The binomial/nonlinear interpolation method was used to calculate LC50 values using the number of dead test organisms and EC50 values using the number of dead and affected organisms. Calculations were performed using the initial measured concentrations of the test substance. The NOEC is the highest concentration of test substance that allowed at least 90% survival and did not cause sublethal effects.

Any other information on results incl. tables

Table 1: Mortality

 

Initial Measured Concentration (mg/L)

Replicate

Number Alive

0 hr

24 hr

48 hr

0

1

5

5

5

 

2

5

5

5

 

3

5

5

5

 

4

5

5

5

8.59

1

5

5

5

 

2

5

5

5

 

3

5

5

5

 

4

5

5

5

13.9

1

5

5

0

 

2

5

5

1

 

3

5

5

0

 

4

5

5

2

21.8

1

5

2

0

 

2

5

5

0

 

3

5

5

0

 

4

5

4

0

37.1

1

5

0

0

 

2

5

0

0

 

3

5

0

0

 

4

5

0

0

60.4

1

5

0

0

 

2

5

0

0

 

3

5

0

0

 

4

5

0

0

98.2

1

5

0

0

 

2

5

0

0

 

3

5

0

0

 

4

5

0

0

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability).

48-hour EC50 = 10.6 mg/L
48-hour LC50 = 11.7 mg/L
48-hour NOEC <8.59 mg/L
Executive summary:

The acute toxicity test to daphnids was performed under static conditions with 6 nominal concentrations (8.1, 14, 23, 38, 64, and 106 mg/L) of test substance and a dilution water control at 20±1°C. The test substance was formulated into a supersaturated stock solution (1000 mg/L) in dilution water, mixed in a sealed container for 24 hours at 30°C, and allowed to equilibrate to test temperature for 48 hours. Water was carefully removed from the mixing vessel to avoid insoluble material and used immediately to initiate the toxicity test. Initial measured concentrations were ND, 8.59, 13.9, 21.8, 37.1, 60.4, and 98.2 mg/L. Because of the volatile nature of the test substance, the test was performed in sealed 40 mL (nominal) test vessels that contained 42 mL of test solution to eliminate head space. Vessels were not opened during the exposure period unless complete mortality occurred. All animals were in good condition at the beginning of the study and 100% of the control daphnids survived the toxicity test. Exposure of daphnids to the test substance resulted in a 48-hour LC50 of 11.7 mg/L, with a 95% confidence interval of 8.59-13.9 mg/L and 48-hour EC50 of 10.6 mg/L, with a 95% confidence interval of 8.59-13.9 mg/L. The 48-hour NOEC was <8.59 mg/L.