Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
Test solutions were not analyzed. Four rather than five test concentrations were used. One replicate with ten daphnids was used per treatment.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Purity: not reported as such

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
Dissolved oxygen concentration, pH, and temperature were measured in all replicates of the dilution water control and test substance concentrations before daphnids were added at test start, and at test end or at total immobility in a test concentration

Test solutions

Vehicle:
no
Details on test solutions:
Test Solution Preparation
Test substance solutions were prepared by dilution from a stock solution of test substance in the testing laboratory’s well water. The stock solution (120 mg/L) was prepared by adding approximately 120.8 mg of test substance to 1 L of the testing laboratory’s well water in a 1-L glass beaker and stirring for approximately 60 minutes. Test solutions were prepared by adding the appropriate volume of the 120 mg/L stock solution to the testing laboratory’s well water in 250-mL glass beakers and stirring for approximately 8 minutes. Based on visual observations, the dilution water control and the 0.12, 1.2, 12, and 120 mg/L test concentrations were clear and colorless with no visible precipitate at test start.
Dilution Water
Dilution water originated from the testing laboratory’s well, which is 480-feet deep and is cased and sealed to bedrock. The hardness of the testing laboratory’s well water is adjusted to approximately 100-140 mg/L as CaCO3 by the flow-proportioned addition of CaCl2. The testing laboratory’s well water is then aerated, passed through a green sand filter to remove iron, and filtered through 50-, 10-, and 3-μm filters to remove particulates. The water is heated or chilled as appropriate and distributed through aged polyvinyl chloride piping. The dilution water is analyzed at least once yearly for major anions and cations, metals, total organochlorine and organophosphate pesticides, and polychlorinated biphenyls. The dilution water meets Organisation for Economic Co-Operation and Development (OECD Guideline 202) and American Society for Testing and Materials (ASTM Standard Guide E 729-88a) specifications.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna were reared at the testing laboratory in 250-mL (1 per beaker) or 1000-mL Pyrex® beakers (10 per beaker at culture initiation) which contained 200 mL or 1000 mL of aerated, filtered testing laboratory well water held at approximately 20°C. Daphnids were fed on a daily basis with 3 mL/L of a yeast, cereal leaves and trout chow (YCT) mixture (standardized to 1700 to 2100 mg/L total solids) and the green alga, Pseudokirchneriella subcapitata, at a rate of approximately 62,500 cells/mL of culture medium. The combination of YCT and alga is equivalent to approximately 0.1-0.2 mg total organic carbon per daphnid. Neonates used in this test were less than 24 hours old and were collected from the 7th brood of 21-day old parent daphnids. Sickness, injury, and abnormalities were not seen and ephippia were not being produced by the parent daphnids. No adult immobility was seen in the cultures used for testing during the 48-hour pretest period. Daphnia magna were identified by labels on the culture beakers and test chambers.

Study design

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

Test conditions

Test temperature:
19.9°C with a range of 19.5 to 20.1°C
pH:
pH
0 Hours: 7.9 – 8.1
48 Hours: 8.0 – 8.2
Dissolved oxygen:
DISOLVED OXYGEN
0 Hours: 8.2-8.3 mg/L
48 Hours: 8.5 mg/L
Nominal and measured concentrations:
Nominal Concentrations: 0.12, 1.2, 12, and 120 mg/L
Details on test conditions:
Four nominal concentrations and a dilution water control were used in this study. The nominal concentrations were 0.12, 1.2, 12, and 120 mg/L test substance.
Pyrex® beakers (250-mL) containing 200 mL of test solution (approximately 6.5-cm test solution depth) were used as test chambers. One replicate test chamber was used per test concentration with 10 daphnids in each chamber. The test chambers were covered with a glass plate during the test.
Daphnia magna neonates, less than 24 hours old, were used in this study. Daphnids were not fed during the test. Addition of daphnids to test solutions was initiated after mixing of the test solutions was completed. Immobility and behavioral observations were made daily. The criterion for the effect (immobility) was a lack of reaction to application of a gentle stimulus.
A recirculating waterbath was used to maintain mean temperature in the test chambers during the 48-hour test at approximately 19.9°C with a range of 19.5 to 20.1°C. A photoperiod of 16 hours light (approximately 270 to 390 Lux) and 8 hours darkness was employed which included 30 minutes of transitional light (14 to 36 Lux) preceding and following the 16-hour light interval.
Dissolved oxygen concentration, pH, and temperature were measured in all replicates of the dilution water control and test substance concentrations. These measurements were taken before daphnids were added at test start, and at test end or at total immobility of a test concentration.
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
16.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 10.3 to 91.1 mg/L (95% fiducial limits)
Details on results:
Exposure of daphnids to the dilution water control and nominal test substance concentrations of 0.12, 1.2, 12, and 120 mg/L resulted in 0, 0, 10, 30, and 100% immobility, respectively, at the end of 48 hours. No immobility or sublethal effects were seen in the dilution water control test organisms. The highest nominal concentration causing no immobility at test end was 0.12 mg/L. The lowest nominal concentration causing 100% immobility at test end was 120 mg/L. Nominal test substance concentrations were used for calculation of EC50 values.
The 48-hour EC50 for test substance, based on nominal concentrations and immobility, was 16.2 mg/L with 95% fiducial limits of 10.3 to 91.1 mg/L.(3,4,5,6).
Reported statistics and error estimates:
95% fiducial limits of 10.3 to 91.1 mg/L

Applicant's summary and conclusion

Conclusions:
The 48-hour EC50, based on nominal concentrations and immobility, was 16.2 mg/L with 95% fiducial limits of 10.3 to 91.1 mg/L.
Executive summary:

The acute toxicity of test substance to the water flea, Daphnia magna (less than 24 hours old) was determined in an unaerated, 48-hour, static test. The study was conducted with 4 concentrations of test substance and a dilution water control at a mean temperature of 19.9°C (range of 19.5-20.1°C). One test chamber was used per test concentration with 10 test organisms in each chamber. Based on visual observations, the dilution water control and the 0.12, 1.2, 12, and 120 mg/L test concentrations were clear and colorless with no visible precipitate at test start. All water quality parameters were within acceptable limits during the exposure.

Exposure of daphnids to the dilution water control and nominal test substance concentrations of 0.12, 1.2, 12, and 120 mg/L resulted in 0, 0, 10, 30, and 100% immobility, respectively, at the end of 48 hours. No immobility or sublethal effects were seen in the dilution water control test organisms. The highest nominal concentration causing no immobility at test end was 0.12 mg/L. The lowest nominal concentration causing 100% immobility at test end was 120 mg/L. Nominal test substance concentrations were used to calculate the 48-hour EC50 value. The 48-hour EC50, based on nominal concentrations and immobility, was 16.2 mg/L with 95% fiducial limits of 10.3 to 91.1 mg/L.