Reaction mass of hentriacontan-16-one and pentatriacontan-18-one and tritriacontan-16-one

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2018-01-22 to 2018-01-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch No.: FK650468
Purity: 100%

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

- Formulation: A saturated test item solution (nominal loading rate of 100 mg/L) was prepared by dispersing/dissolving the amount of test item into the test medium (OECD Medium) two days before the start of the study. This solution was shaken for about 24 hours at approximately 30°C and then equilibrated for about 24 hours at approximately 20°C. The non-dissolved test material was removed by filtration through a fine (0.22 μm) filter to give the 100 % saturated solution.

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Strain number: 61.81 SAG (identical strains: CCAP 278/4; UTEX 1648; ATCC 22662)
- Source: supplied by the SAG
- Justification of species: The species used, being a fast-growing species, is convenient for culturing and testing and is a recommended species by relevant guidelines.
- Breeding conditions: Stock cultures are small algal colonies that are inoculated onto agar regularly. These are transferred to fresh agar medium at least once every two months and are maintained under standardised conditions according to the test guidelines.
The pre-culture is intended to give a quantity of algae suitable for the inoculation of test cultures. The preculture was prepared with the OECD algal growth medium, incubated under the same conditions as the test and used when still growing exponentially, after an incubation period of three days. When the algal cultures contain deformed or abnormal cells, they were discarded.

Test type:

static

Water media type:

freshwater

Remarks:

OECD medium

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

21.8-23.2ºC

pH:

7.41-8.03

Nominal and measured concentrations:

Nominal: 100% saturated solution

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL sterile Erlenmeyer flasks
- Type (delete if not applicable): closed, covered with air-permeable stoppers
- Material, size, headspace, fill volume: 100 mL test solution
- Initial cells density: 1E+04 algal cells per mL test medium.
- Control end cells density: 68.33E+04 cell/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted algal growth medium (OECD medium, according to OECD 201)

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuously illuminated
- Light intensity and quality: 7813 lux (equivalent to ~106 μE/m2/s), ensured with fluorescent lamps

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber, determined at 24, 48 and 72 hours after starting the test
- Other: Microscopic observation of the algal cells in each concentration and in the control was performed (at 24h, 48h and 72h) to detect any abnormal appearance of the algae.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.1%, 1%, 10%, 100% saturated solution
- Results used to determine the conditions for the definitive study: no toxic effect was observed during the preliminary range-finding test

Reference substance (positive control):

yes

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Morphological deviations of the algal cells: There were no any observed morphological deviations during the experiment
- Average specific growth rates: The results of the statistical evaluation (based on 2 Sample t-Test; α=0.05) show that the 0-72 h average specific growth rate was not statistically significantly different from the untreated control value
- Areas under the growth curves: the results of the statistical evaluation (based on 2 Sample t-Test; α=0.05) show that the 0-72 h areas were not statistically significantly different from the untreated control value
- Yield: The results of the statistical evaluation (based on 2 Sample t-Test; α=0.05) show that the 0-72 h yield was not statistically significantly different from the untreated control value

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- The 72h ErC 50: 0.88 mg/L, (95 % confidence limits: 0.81 – 0.96 mg/L)
- The 72h EbC 50: 0.63 mg/L, (95 % confidence limits: 0.58 – 0.69 mg/L)
- The 72h EyC 50: 0.53 mg/L, (95 % confidence limits: 0.49 – 0.58 mg/L)

Reported statistics and error estimates:

For the determination of the LOEC and NOEC, the calculated mean biomass, growth rates and yield at the test concentrations were tested on significant differences to the control values by 2 Sample t-Test (α = 0.05) by TOXSTAT software

Validity criteria fulfilled:

yes

Conclusions:

The test item had no toxic effect at saturation; the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.

Executive summary:

The effect of test item was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata, over an exposure period of 72 hours based on OECD201.

Because a toxic response was not observed during the preliminary concentration range-finding test, a Limit Test was carried out using only one test concentration at the solubility level of the test item in the test medium (100 % saturated solution) and one control group.

The test design included six replicates at test concentration and six replicates for the untreated control.

Under the conditions of this algal growth inhibition test the calculated endpoints for the effect of test item were the following:

The 72h EbC50 value (biomass): > 100 % saturated solution (nominal)

The 72h ErC50 value (growth rate): > 100 % saturated solution (nominal)

The 72h EyC50 value (yield): > 100 % saturated solution (nominal)

The 72h No-Observed Effect Concentration (NOEC): 100 % saturated solution (nominal)

The 72h Lowest Observed Effect Concentration (LOEC): > 100 % saturated solution (nominal)

Based on the results of this study, the test item had no toxic effect at saturation; the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.

Description of key information

The test item had no toxic effect at saturation; the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.

Additional information

The effect of test item was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata, over an exposure period of 72 hours based on OECD201.

Because a toxic response was not observed during the preliminary concentration range-finding test, a Limit Test was carried out using only one test concentration at the solubility level of the test item in the test medium (100 % saturated solution) and one control group.

The test design included six replicates at test concentration and six replicates for the untreated control.

Under the conditions of this algal growth inhibition test the calculated endpoints for the effect of test item were the following:

The 72h EbC50 value (biomass): > 100 % saturated solution (nominal)

The 72h ErC50 value (growth rate): > 100 % saturated solution (nominal)

The 72h EyC50 value (yield): > 100 % saturated solution (nominal)

The 72h No-Observed Effect Concentration (NOEC): 100 % saturated solution (nominal)

The 72h Lowest Observed Effect Concentration (LOEC): > 100 % saturated solution (nominal)

Based on the results of this study, the test item had no toxic effect at saturation; the EC50 results and the LOEC are higher than the solubility level of the test item in the test medium.