Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
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)
Analytical monitoring:
yes
Details on sampling:
Sampling schedule: The limit concentration, the solvent control and the control were analytically verified via GC-MS/MS after 0 hours (start of exposure), 24 hours and 72 hours (end of the exposure) with algae.
Sampling and pre-treatment: Separate replicates for the test item analysis after 0 hours, 24 hours and 72 hours were prepared in the original test vessels with algae at the start of the exposure and incubated under test conditions until analysis, to avoid any losses via volatilization during handling.
Vehicle:
yes
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: Pseudokirchneriella subcapitata HINDAK CCAP 278/4
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa {CCAP) SAMS Research Services Ltd Dunstaffnage Marine Laboratory Dunbeg, OBAN; Argyll PA37 1QA; Scotland, UK
- Age of inoculum (at test initiation): A three days old preculture, prepared in dilution water, was used as inoculum.
- Method of cultivation: Fresh stocks are prepared every month on Z-Agar. Light intensity amounts to 2590 - 5180 lux corresponding to 35 - 70 µE m-2 s-1 for 24 hours per day.

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Hardness:
The medium had a nominal hardness of 0.24 mmol Ca+Mg/L.
Test temperature:
Nominal range: 21 - 24 °C, controlled at ± 2 °C
pH:
OECD TG 201 medium: pH 7.5 +/- 0.2
environmental conditions of the

Geometric mean measured test item pH-value
concentration
[pg/L] Start; 0 hours End; 72 hours
0.274 8.06 9.03
Solvent control 8.09 9.12
Control 8.07 9.11
Nominal and measured concentrations:
Nominal concentration: 1 µg/L (limit concentration)
Geometric mean measured concentration: 0.274 µg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Sterile headspace flasks, volume: 59 ml, with aluminium tops with PTFE seals
- Type (delete if not applicable): closed
- Initial cells density: Nominal:approximately 5 x 103 - 104 cells/ml; Acutal: 6442 cells/ml
- No. of organisms per vessel:
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 24 hours/day light
- Light intensity and quality: Approximately 4440 to 8880 lux, corresponding to 60 to 120 μE*m·2*s·1

Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.274 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.274 µg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
NominThe measured concentration in the limit concentration was 86% at the start of the exposure (0 hours), 48% after 24 hours and 3% at the end of the exposure (72 hours) of the nominal values. The decrease was expected, since the tested concentration was above the limit of solubility of the test item. The measured concentration in the limit concentration was 0.861 μg/L at the start of the exposure (0 hours), 0.477 μg/L after 24 hours and < LOQ at the end of the exposure (72 hours).
Results with reference substance (positive control):
The toxicity of potassium dichromate to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined over a period of 72 hours from 2018-09-25 to 2018-09-28 (with headspace) and 2018-07-10 to 2018-07-13 (without headspace), respectively. The reference item toxicity is in the valid range which was established by calculation of the average of the historic reference data since 2005, and the limits were set using the threefold standard deviation of these values.

EC-values of Laurylacrylat 12 (0 - 72 hours) based on geometric mean measured test item concentration [μg/L]

 

Inhibition of Growth Rate

ErC10

> 0.274

ErC20

> 0.274

ErC50

> 0.274

 

Inhibition of Yield

EyC10

> 0.274

EyC20

> 0.274

EyC50

> 0.274

Validity criteria fulfilled:
yes
Conclusions:
In this study, Laurylacrylat 12 did not inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours when tested above its maximum water solubility. All effect levels are based on geometric mean measured test item concentration. The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 0.274 μg/L.

Description of key information

The test substance Laurylacrylate 12, was tested in a toxicity study to algae. The EC50 and EC10-values (growth rate and biomass) were > 0.274 µg/L.

There were further studies available for different read across substances.

The test substance 2-Propenoic acid, C12-14-alkyl acrylate, was tested in a toxicity study to algae. The EC50 and EC10-values (growth rate) were 51.6 mg/L and 24.8 mg/L.

In the toxicity to aquatic algae test the median effect concentration with respect to growth rate (ErC50 /0-3 days) of the test substance 2-Propenoic acid, C16-18-alkyl esters (read across) was calculated to be 278 mg/L and the yield (EyC50/0–3 days) was calculated to be 181 mg/L based on the loading rate. The no-observed-effect concentration (NOEC) with respect to growth rate and yield was 100 mg/L loading rate.

In an algae growth inhibition study, water accommodated fractions of the test substance 2 -Propenoic acid, C18-26-alkyl ester were tested on their effects on the growth of the freshwater green alga Desmodesmus subspicatus over the period of 72 hours. The observed dose-response relationship was ambiguous. Therefore, no calculation of effect loading (EL) values was possible. Instead, EL-values were approximated directly from the observation data.
The EL50 basic for effect growth rate (72 h) was greater than 100 mg/L.

In this 72-h growth inihibition test with Desmodesmus subspicatus the 72-h EC50, of 2 -Propylheptyl acrylate, based on growth rate was determined as 84.9 mg/L and the overall NOEC as 10 mg/L. Both EC50 as well as the NOEC are exceeding the water solubility of 2-Proylheptyl acrylate of 0.5 mg/L by far; no toxicity was observed in the range of the water solubility

Key value for chemical safety assessment

Additional information

The toxicity of Laurylacrylat 12 to the unicellular freshwater green alga Pseudokirchnerie/la subcapitata was determined according to the principles of OECD 201. The aim of the study was the determination of NOEC, LOEC, EC10- , EC20- and EC50- values of growth rate and yield over a period of 72 hours. The water solubility of the test substance is < 1 μg/L. The study was conducted under static conditions with an initial cell density of 6442 cells/ml. One limit concentration with a loading of 1.0 μg test item/L was prepared by dissolving the test item in DMF at a concentration of 20 μg/ml DMF. Six replicates were used for the limit concentration, the control and solvent control.

In this study, Laurylacrylat 12 did not inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours when tested above its maximum water solubility. All effect levels are based on geometric mean measured test item concentration. the EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 0.274 µg/L.

The read across substance mixture of laurylacrylate (CAS No.: 2156-97-0) and tetradecylacrylate (CAS No.: 21643-42-5) was tested in a toxicity 72 h-study to algae. The test concentrations were 0, 1, 2.5, 5, 10, 25 and 50 mg/L.The EC50 and EC10-values (growth rate) were 51.6 mg/L and 24.8 mg/L. The EC50 and EC10-values (biomass) were 51.6 mg/L and 21.3 mg/L, both values exceeding by far the water solubility of < 1 µg/L.

The toxicity to aquatic algae test was conducted according to the OECD guideline 201. The median growth inhibiting concentration (ErC50/EyC50) and the low-effect concentrations (ErC10/EyC10,ErC20/EyC20), based on the average specific growth rate and the yield (algal biomass production) within 3 days, of 2-Propenoic acid, C16-18-alkyl esters to the green alga Desmodesmus subspicatus, were investigated over a period of 72 h. The nominal concentrations of the test substance were 1.0, 3.2, 10, 32, 100 and 320 mg/L. These test concentrations were prepared using the water accommodated fraction (WAF) approach. Three parallel test vessels were used for each concentration of the test substance. GC-FID analyses of the test substance concentrations were conducted at the beginning and at the end of the exposure period. The analysis revealed that all test substance concentrations were below the quantification limit (<1 µg/L). Thus, the evaluation was based on the nominal loading rates.

With respect to algal growth rate inhibition, the following significant effects as compared to the untreated controls were observed at the respective nominal loading rates: 320 mg/L (65%), 10 mg/L (8%). No significant effects (determined by Dunnett’s Test) were observed at all other test concentrations. No significant effects were observed at the loading rates of 32 and 100 mg/L, and therefore, it can be concluded, that the observed effects at the loading rate of 10 mg/L were presumably due to an artifact. Thus, these results were excluded from the evaluation.

Based on these data, the median effect concentration with respect to growth rate (ErC50 /0-3 days) of the test substance to Desmodesmus subspicatus was calculated to be 278 mg/L loading rate (95% confidence limits: 212-296 mg/L). The low effect concentrations with respect to growth rate, ErC10 and ErC20, were 169 mg/L (95% confidence limits: 49.3–218 mg/L) and 203 mg/L (95% confidence limits: 84.5-244 mg/L), respectively. The no-observed-effect concentration with respect to growth rate (NOErC) was 100 mg/L loading rate. For the endpoint yield (biomass production), the following significant effects as compared to the untreated controls were observed at the respective loading rates: 320 mg/L (95%), 10 mg/L (29%). No significant effects (determined by Dunnett’s Test) were observed at all other test concentrations. No significant effects were observed at the loading rates of 32 and 100 mg/L, and therefore, it can be concluded, that the observed effects at the loading rate of 10 mg/L were presumably due to an artifact. Thus, these results were excluded from the evaluation. Based on these data, the median effect concentration with respect to yield (EyC50/0–3 days) of the test substance to Desmodesmus subspicatus was calculated to be 181 mg/L loading rate (95% confidence limits: 1140-230 mg/L). The low effect concentrations with respect to yield, EyC10 and EyC20, were 117 mg/L (95% confidence limits: 76.7-150 mg/L) and 138 mg/L (95% confidence limits: 97.0-173 mg/L), respectively. The no-observed-effect concentration with respect to yield (NOEyC) was 100 mg/L loading rate.

The toxicity of the test substance 2 -Propenoic acid, C18-26-alkyl ester to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD 201. The aim of the study was to assess the effects on growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 4910 cells/mL. Based on a preliminary test, 9 water accommodated fractions (WAF) were tested in a geometrical series with a dilution factor of V10, nominal: 0.0100 - 0.0320 - 0.100 - 0.320 - 1.00 - 3.20 - 10.0 -32.0 - 100 mg/L. Three replicates were tested for each test item loading and six replicates for the control. The environmental conditions were within the acceptable limits. The concentrations of test item were analytically verified via analysis of the total organic carbon (TOC) at the start of the exposure and at the end of the exposure. The results of the carbon analysis showed that there was no relationship between the nominal loading levels and the measured TOC values. TOC analysis was carried out to determine the content of the test item in water as a sum parameter. No specific analysis was possible as the test item is a mixture of different compounds. In addition, the observed dose-response relationship was ambiguous as there was no clear relation between concentration and effect. Therefore, no calculation of EL-values was possible. Instead, EL-values were approximated directly from the observation data. All effect values given are based on nominal test item loadings of the test item. The EL50 basic for effect growth rate (72 h) was greater than 100 mg/L. The observed effects did not follow a considered dose-response curve. Therefore, the presented effect levels (especially Ey20) are of low reliability and should be considered with extreme care. The effects may be caused by the presence of undissolved test item in the test medium, since the preparation of the water accomodated fraction did not include a filtration step. Hence, it cannot be excluded that particles of the test item might have caused the observed response.

Concerning the algal toxicity, a GLP algae growth inhibition test according to OECD guideline 201 and EU method C.3 with the algae Desmodesmus subspicatus was performed with 2 -Propylheptyl acrylate. The algae was exposed to test concentrations of 0 (control), 4.6, 10, 22, 46, 100 mg/L with 6 replicates for the control and 3 replicates for each test concentration. Due to the photolytical instability of 2-propylheptyl acrylate the test concentrations could not be quantified by analytical methods. No effects on algal growth or yield were observed in test groups with measured initial concentrations up to the water solubility limit of the test substance (10 mg/L nominal). All effects on algal growth occurred in test groups with measured initial concentrations greater than the water solubility limit of the test substance. It is likely that these observed effects were due to soluble minor contaminants associated with the test substance, and not to the test substance itself. The measured concentrations deviated markedly from the nominal concentrations; however, mean measured concentrations could not be calculated. According to OECD guideline 23, for tests with chemicals that can not be quantified by analytical methods at the concentrations causing effects, the effect concentration can be expressed based on the nominal concentrations. The results in this study are consistent with all validity criteria and the test is valid according to the guidelines used for the study. No deviations from test guidelines or other incidents occurred during the course of the reported test. Based on the growth rate the EC50 (72 h) was determined to be 84.9 mg/L. The NOEC based on the growth rate is 10 mg/L , both values (NOEC and EC50) are exceeding the water solubility of 2 -Propylheptyl acrylate of <0.2 mg/L by far (BASF SE 2009).