Registration Dossier

Ecotoxicological information

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
long-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:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Deviations:
no
Remarks:
Study 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%

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations Sampled: (measured values) 0, 0.648, 1.72, 4.19, 9.1, 21.8 mg/L; (nominal values) 0, 1.28, 3.20, 8.00, 20.0, 50.0 mg/L)
- Sampling Times: Fresh media (0-hour): Days 0, 1, 5, 6, 12, 19 and Old media (48-hours) Days: 1, 2, 6, 7, 8, 13, 20
- Sample storage conditions before analysis: Stored at 6 ± 2ºC

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION: The stock solution (100 mg/L) was prepared with dilution water one day prior to application. For preparation of the stock solution 63.3 µL/L of the test substance was added below the water surface. The stock solution was shaken with an overhead shaker adjusted to 20 rpm for 24 hours at room temperature. Test concentrations were achieved by serial dilution.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia (water flea)
- Strain/clone: STRAUS/Clone 5
- Feeding during test: At least 5 times per week. For each test vessel Pseudokirchneriella subcapitata (0.470 - 0.765 mL) and Desmodesmus subspicatus (0.890 - 1.05 mL) suspensions were added as food.

ACCLIMATION
- Acclimation period: not reported

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Post exposure observation period:
none

Test conditions

Hardness:
Hardness ranged from 165 - 178 mg CaCO3
Test temperature:
Temperature ranged from 20.9 - 22.0 °C
pH:
pH ranged from 7.78 - 8.97
Dissolved oxygen:
Dissolved oxygen ranged from 8.19 - 9.87 mg/L
Nominal and measured concentrations:
Nominal: 0, 1.28, 3.20, 8.00, 20.0, and 50.0 mg/L
Measured: 0, 0.648, 1.72, 4.19, 9.10 and 21.8 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Sealed glass flask
- Renewal rate of test solution (frequency/flow rate): Renewed daily
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

OTHER TEST CONDITIONS
- Photoperiod: 16/8 light/dark cycle
- Light intensity: Maximum 20 µE me-2 se-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Mortality of parent Daphnia, daily
- First appearance of juveniles (neonates), daily
- Condition of parent Daphnia (swimming behavoir, number of males, winter eggs, other abnormalities), daily
- Total length and dry body weight of parent Daphnia, daily

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0, 1, 10, and 100 mg/L
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
yes

Results and discussion

Effect concentrationsopen allclose all
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
>= 6.17 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: Parental survival
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
>= 4.19 - < 9.1 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: Offspring survival
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
>= 1.72 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: Offspring survival
Duration:
21 d
Dose descriptor:
LOEC
Effect conc.:
>= 4.19 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
reproduction
Remarks on result:
other: Offspring survival
Details on results:
Mortality of parent animals: At concentrations of 9.10 and 21.8 mg/L mortality was 100%

The mean dry weght of surviving parent animals decreased with increasing concentration of test substance. For samples 0, 0.648, 1.72, and 4.19 mg/L the respective weights were 1.31, 1.13, 0.97, and 0.89 mg.
Results with reference substance (positive control):
Reference substance: Potassium dichromate
Test concentrations: 0.625, 1.00, 1.60, and 2.56 mg/L
Range of validity: 1.0 mg/L < EC50 (24 h) < 2.5 mg/L, according to AQS P 9/2 (clone 5)
Range of validity: 0.6 mg/L < EC50 (24 h) < 2.1 mg/L, according to OECD 202 (clone A)
Test duration: 24 hours
Reported statistics and error estimates:
The NOEC and LOEC for reproduction were determined directly from the results. Significant deviations were determined in comparison to the control group using statistical standard procedures as Normality Test, Equal Variance Test and Analysis of Variance. The EC50 value of the adult mortality was determined by calculating the geometric mean of the highest concentration causing no adult mortality and the lowest concentration causing 100% adult mortality, because standard methods of calculating the EC50 value were not applicable to the data obtained.

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).

EC50 adult mortality = 6.17 mg/L
EC50 reproduction ≥4.19, but <9.1 mg/L
NOEC reproduction = 1.72 mg/L
LOEC reproduction = 4.19 mg/L
Executive summary:

A semi-static, 21-day reproduction test in Daphnia magna was performed at measured concentrations of 0, 0.648, 1.72, 4.19, 9.1, and 21.8 mg/L. The average number of juveniles per parent in the control group was 98 after 21 days. The reproductive output was statistically significantly reduced (by 28.6%) only at the mean measured concentration of 4.19 mg/L when compared to control. No juveniles were produced at concentrations of 9.10 and 21.8 mg/L as adult mortality was 100%. The adult mortality was 100% at the mean measured concentrations of 9.10 and 21.8 mg/L after 21 days. The test substance did not induce significant mortality (>20%) of parental animals at any of the other concentrations and in the control. At the control as well as mean measured concentrations 0.648 and 4.19 mg/L all daphnids survived until the end of the study. The EC50 for adult mortality after 21 days was calculated to be 6.17 mg/L.

The Lowest Observed Effect Concentration (LOEC) and the No Observed Effect Concentration (NOEC) based on reproductive output were, respectively, 4.19 and 1.72 mg/L.

 

Related to the total number of produced juveniles (dead + alive) the percentage of stillborn juveniles and aborted eggs was ≤4% at the mean measured concentrations 0.648, 1.72 mg/L, and control. Only at the mean measured concentration of 4.19 mg/L was there a noticeable increase (13%) in stillborn juveniles and aborted eggs.

 

No males and ephippia (winter eggs) occurred in control or test groups.

 

The mean day of release of the first brood was day 8.4 at the control group. At the mean measured concentrations of 0.648 and 4.19 mg/L the mean day of release of the first brood was in the range of 8.5 to 8.9. The first brood was released until day 9 by all daphnids of the control group and the test concentration levels except one parent animal each at concentrations 0.648 and 1.72 mg/L. Four broods were released by all surviving animals of the test and control groups.

 

The dry body weight and total length of the parent daphnids in the test concentrations were comparable to the control group. The mean dry body weight at the tested levels ranged from 0.89 to 1.13 mg per daphnid. The mean dry body weight at the control was 1.31 mg per daphnid. The mean total body length for control daphnids was 5.40 mm and, for tested concentrations, in the range of 4.85 to 5.40 mm.