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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the O.E.C.D. test guideline 201 with GLP compliance.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 201 (Alga, Growth Inhibition Test)
Nominal concentrations only.
GLP compliance:

Test material

Test material form:
liquid: viscous
Details on test material:
As per IUCLID Sections 1.1. 1.2. and 4.1.

Sampling and analysis

Analytical monitoring:

Test solutions

Details on test solutions:
Pre-study work was carried out to determine whether stirring for a prolonged period produced significantly higher levels of total organic carbon, as an indicator of soluble organic substances in the WAF. A WAF of a nominal loading rate of 100 mg/L was prepared, in duplicate, in deionized reverse osmosis water. One loading rate was stirred for a period of 23 hours and the other for a period of 71 hours. After a 1-Hour standing period the mixtures were then removed by siphon and samples taken for Total Organic Carbon analysis.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The test was carried out using Pseudokirchneriella subcapitata strain CCAP 278/4. Liquid cultures of Pseudokirchneriella subcapitata were obtained from the Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd, Scottish Marine Institute, Oban, Argyll, Scotland. Master cultures were maintained in the laboratory by the periodic replenishment of culture medium. The master cultures were maintained in the laboratory under constant aeration and illumination at 21 ± 1 °C.
Prior to the start of the test sufficient master culture was added to approximately 100 mL volumes of culture media contained in conical flasks to give an initial cell density of approximately 103 cells/mL. The flasks were plugged with polyurethane foam stoppers and kept under constant agitation by orbital shaker (100 – 150 rpm) and constant illumination at 24 ± 1 °C until the algal cell density was approximately 104 – 105 cells/mL.

Study design

Test type:
Water media type:
Limit test:
Total exposure duration:
72 h
Post exposure observation period:

Test conditions

No data
Test temperature:
8.0-8.1 treminal
Dissolved oxygen:
no data
Nominal and measured concentrations:
10, 20, 40, 80 and 160 mg/L nominal.
Details on test conditions:
As in the range-finding test 250 mL glass conical flasks were used. Six flasks each containing 100 mL of test preparation were used for the control and three flasks each containing 100 mL were used for each treatment group.
The control group was maintained under identical conditions but not exposed to the test item.
Pre-culture conditions gave an algal suspension in log phase growth characterized by a cell density of 9.09 x 105 cells per mL. Inoculation of 1 liter of test medium with 5.5 mL of this algal suspension gave an initial nominal cell density of 5 x 103 cells per mL and had no significant dilution effect on the final test concentration.
The flasks were plugged with polyurethane foam bungs and incubated (INFORS Multitron Version 2 incubator) at 24 ± 1 °C under continuous illumination (intensity approximately 7000 lux) provided by warm white lighting (380 – 730 nm) and constantly shaken at approximately 150 rpm for 72 hours.
Samples were taken at 0, 24, 48 and 72 hours and the cell densities determined using a Coulter® Multisizer Particle Counter.
Reference substance (positive control):
potassium dichromate

Results and discussion

Effect concentrations
72 h
Dose descriptor:
Effect conc.:
> 160 mg/L
Nominal / measured:
Conc. based on:
test mat.
Basis for effect:
cell number
Details on results:
At 160 mg/L test substance after 72 hr the relative percent cell growth inhibition was 11%.
Results with reference substance (positive control):
A positive control (Harlan Study Number: 41205049) used potassium dichromate as the reference item at concentrations of 0.25, 0.50, 1.0, 2.0 and 4.0 mg/L.
ErC50 (0 – 72 h) : 1.1 mg/L; 95% confidence limits 1.0 – 1.3 mg/L
EyC50 (0 – 72 h) : 0.70 mg/L*
The results from the positive control with potassium dichromate were within the normal ranges for this reference item.
Reported statistics and error estimates:
Statistical analysis of the growth rate data was carried out for the control and all loading rates using one way analysis of variance incorporating Bartlett's test for homogeneity of variance (Sokal and Rohlf 1981) and Dunnett's multiple comparison procedure for comparing several treatments with a control (Dunnett 1955). There were no statistically significant differences between the control, 10, 20, 40 and 80 mg/L loading rate WAFs (P≥0.05), however the 160 mg/L loading rate was significantly different (P<0.05) and, therefore the "No Observed Effect Loading Rate" (NOEL) based on growth rate was 80 mg/L loading rate WAF. Correspondingly the "Lowest Observed Effect Loading Rate" (LOEL) based on growth rate was 160 mg/L loading rate WAF.

Applicant's summary and conclusion

Validity criteria fulfilled:
The EC50 value for the test substance in this study of >160 mg/L demonstrates that it is not toxic to algae under the conditions of the study.
Executive summary:

The test substance, 4,4'-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane, reaction products with fatty acids, C18-unsatd., dimers, was accesed for toxicity to green algae in a GLP, O.E.C.D. test gudeline 201 study. The EC50 value for the test substance in this study of >160 mg/L demonstrates that it is not toxic to algae under the conditions of the study.