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EC number: 258-436-4
CAS number: 53220-22-7
Reproduction (Primary endpoint)No statistical difference was detected between the solvent control and the only test concentration. The NOEC for reproduction can therefore be expressed as 120 μg/L (nominal) or as 44.7 μg/L (estimated time weighted mean) concentration. Due to these values exceeding the water solubility of the test substance the test material may also be concluded to have no effects on the reproduction of Daphnia magna at its water solubility limit. ECx values were not possible to calculate due to their being no dose response in the data set.
LengthNo statistical difference was detected between the solvent control and the only test concentration. The NOEC for reproduction can therefore be expressed as 120 μg/L (nominal) 44.7 μg /L (estimated time weighted mean) concentration. Due to these values exceeding the water solubility of the test substance, the test material may also be concluded to have no effects on the length of Daphnia magna at its water solubility limit. ECx values were not possible to calculate due to their being no dose response in the data set.
Dry WeightSufficient replicates for a valid statistical analysis were not available. However, the average dry weight per daphnia at the only test concentration exceeded that of the control. Supporting the findings of the other two endpoints already described.
The analytical method was found to be sufficiently sensitive and robust for determining the test substance concentration in this study at t = 0, 48 and 72 hours between refreshment making a time weighted mean calculation possible. However, the instable nature of the test material and its poor water solubility and adsorbing properties do mean that analysis of nominal concentrations lower than 120 μg/L will result in greater variability and difficulty in analysis. However, if a sufficiently large sample is taken from the test replicate (20 mL) detection of nominal concentrations reproducibly down to 10 μg/L is considered feasible. The chemical analysis demonstrated a good level of initial nominal recovery and complete absorption to the algae biomass. No test material in the water phase could be detected.
Table 1.The number of living juveniles per parent animal at each nominal test concentration, the mean number of neonates per concentration and the coefficient of variance.
Reproduction Day 21
M = Mortality parent animal
Table 2: Length of the test organisms in standard units (Day 21)
The measurement took place via a standard scale in the binocular microscope eyepiece. This measurement is unitless and changes dependent on magnification used. It is used for comparison purposes only to determine if a length difference occurs.
Table 3: The dry weight of the test organisms (Day 21)
M (dish full) (g)
M dish empty (g)
No. of daphnids
Average weight (mg)
Concentration of the test item (in µg/L)
T = 0
T = 24 h
T = 48 h
T = 72 h
control, water phase
control, algae extract
control M4, water phase
Demi water spiked rep. 1
Demi water spiked rep. 2
Demi water spiked rep. 3
120 µg/L rep. 1 water phase
120 µg/L rep. 2 water phase
120 µg/L rep. 3 water phase
120 µg/L rep. 1 algae extract
120 µg/L rep. 2 algae extract
120 µg/L rep. 3 algae extract
n.d. = not determined
Analytical method validity
The analytical method was shown to be capable of detecting >76 to <120 % of the nominal concentration of the test material in both from the M4 daphnia test medium containing Chlorella vulgaris and in deionized water. Triplicate measurements showed an acceptable level of variation both from the water phase determination and when the test material is extracted from the filtered algae material.
Time weighted average estimation
T = 0 h
Average 12 d (57 % of test)
Average 9 d (43 % of test)
In the course of this study the toxicity of the test substance dissolved in fresh water, on the reproductive efficacy of Daphnia magna STRAUS - clone 5, in a semi-static limit test according to OECD Guideline No. 211 (OECD, 2012), was assessed.The primary test criterion used to indicate the toxicity of the test substance was reproductive capacity expressed as the total number of neonates per surviving parent animal at the end of the study. The test was conducted at a single limit test concentration of 120 µg/L. A test replicate using test medium and 100 μL/L of acetone served as the control as well as an additional control in test medium only. Data on parental length and dry weight was also generated for use in determining a secondary endpoint as additional information.No statistical difference was detected between the reproduction in the solvent control and the only test concentration. The NOEC for reproduction can therefore be expressed as 120 μg/L (nominal) or as 44.7 μg/L (estimated time weighted average) concentration.No statistical difference was detected between the length of the adult organisms in the solvent control and the only test concentration. The NOEC for length can therefore be expressed as 120 μg/L (nominal) or as 44.7 μg /L (estimated time weighted average) concentration.The quality criteria for the performance of the test met the guideline requirements and the analytical method used was able to detect the test material with sufficient sensitivity, accuracy and reproducibility.The test material was concluded to have no chronic effects on Daphnia magna up to its solubility limit in test medium and was concluded to partition completely to the algae biomass and was not detectable in the water phase but was detectable after extraction from the algae biomass.
Based on a worst-case exposure far in excess of a realistically achievable environmental concentration, no effects to any of the assessed endpoints were observed, therefore, the NOEC was determined to be 120 µg/L (nominal) or 44.7 µg/L (TWA).
Supporting data from a read-across substance are additionally provided:
In order to assess the toxicity of Dihexadecyl peroxodicarbonate in an aquatic environment, a Daphnia magna reproduction test under flow through conditions at the maximum achievable solubility in test medium was conducted in accordance with OECD Guideline No. 211. Testing was conducted in compliance with OECD principles of Good Laboratory Practice. Two modifications to the guideline were applied. Due to the lack of toxicity in acute and chronic preliminary testing, a single concentration at the maximum achievable concentration of the test substance in the test medium was tested. Due to the extremely low solubility of the test substance, chemical analysis was not possible. A flow through system was therefore used to ensure continual exposure and the testing of a realistic worst case scenario. The primary test criterion of toxicity used was reproductive capacity, expressed as the total number of neonates per replicate the end of the test. Secondary endpoints based on time to first brood, juvenile and parent mortality, dry weight and length were also compared in the same manner directly to the corresponding control data for significant differences.
The following validity criteria were respected:
- The average number of juveniles per surviving parent in the control was >60 in both definitive tests.
- No ephippia or abnormal mortality or presence of male daphnia occurred in the culture or in the control for both definitive tests.
- The coefficient of variation in the controls were all < 25 %.
- The mortality in the control did not exceed 20% in the second definitive test.
The following validity criterion was not met:
- In the first definitive test the control mortality was exceeded slightly.
Due to the slightly elevated mortality in the control the study was repeated in the form of a second identical definitive test. Generated test data was then pooled due to both tests being having run for the full 21 day period with good control reproduction.
No significant differences from the control were detected for reproduction and dry weight. No difference in time to first brood was observed and no juvenile or parent mortality was observed. The data for length did show significant difference from the control. Due to the vast majority of the data indicating no effects, the test substance was concluded as having no chronic effects on Daphnia Magna at its solubility limit in the test medium.
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