Icosyl acrylate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 2012-01-26 to 2013-01-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

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.

Details on test solutions:

PREPARATION OF THE WATER ACCOMODATED FRACTIONS:
- Nine water accommodated fractions were prepared with nominal loadings of the test item in the range of 0.0100 to 100 mg/L, set up in a geometric series with a separation factor of V10: 0.0100, 0.0320, 0.100, 0.320, 1.00, 3.20, 10.0, 32.0 and 100 mg/L. For each loading level, an appropriate amount of the test item was weighed out.
The test item was applied directly onto a glass slide. The glass slide with the test item was inserted in a brown glass flask with an appropriate amount of dilution water. These dispersions were shaken for at least 72 hours with 20 rpm at room temperature. After a separation phase of 1 hour, the WAF was taken from the homogeneous liquid phase.

TEST LOADINGS: Per definition of the WAF, all terms related to concentration level are given as loading level because partly dissolved compounds and mixtures cannot be related to concentrations:
- Test loading (nominal): 0.0100, 0.0320, 0.100, 0.320, 1.00, 3.20, 10.0, 32.0 and 100 mg/L.

CONTROL: Six replicates (without test item) were exposed under the same test conditions as the test item loadings.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- Test organism: Desmodesmus subspicatus CHODAT SAG 86.81
- Reason for the selection of the test system: According to the guideline, Desmodesmus subspicatus CHODAT SAG 86.81 is suitable for this kind of study.
- Origin: Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Nikolausberger Weg 18, D-37073 Göttingen.

ACCLIMATATION:
- Preculture: A four day old preculture, prepared in dilution water, was used as inoculum. For the start of the test, the preculture was directly pipetted into each test loading and the control.
- Cultivation at test facility: Fresh stocks are prepared every month on Z-Agar.
- Light intensity amounts to 35-70 µE *mexp-2 * sexp-1 for 24 h per day.
- Culture medium: Nutrient medium Z according to LÜTTGE et al. (1994).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

Nominal hardness 0.24 mmol Ca+Mg/L

Test temperature:

21 - 24 °C (controlled at +/- 2°C)

pH:

8.1 +/- 0.2

Dissolved oxygen:

no data

Nominal and measured concentrations:

Nominal: 0.0100, 0.0320, 0.100, 0.320, 1.00, 3.20, 10.0, 32.0 and 100 mg/L
The concentrations of test item were analytically verified via analysis of total organic carbon (TOC) at the start and the end of the exposure of the nominal test item loadings 3.20 - 10.0 - 32.0 - 100 mg/L and the control. The results show that there is no relation between the nominal loadings and the total organic carbon content. Thus, only nominal concentrations were reported.

Details on test conditions:

TEST SYSTEM
- Duration of the test: 72 hours
- Replicates: 3 replicates each per loading level and 6 for the control
- Test container: Sterile Erlenmeyer flasks (vol. 250 mL) with cotton wool plugs.
- Test volume: 100 mL
- Dilution water: According to the guidelines

TEST MEDIUM
- Preculture: A four day old preculture, prepared in dilution water, was used as inoculum. For the start of the test, the preculture was directly pipetted into each test loading and the control.
- Initial cell density: Nominal: approximately 2 - 5 x 10exp3 cells/mL. Actual: 4.91 x 10exp3 cells/mL
- Application: Application was carried out by adding appropriate volumes of the water accommodated fractions to the replicate test vessels.
- Incubation: The flasks were positioned randomly and repositioned daily.
- Temperature (target): 21 - 24 °C, controlled at ± 2 °C.
- Agitation: Test containers were placed on a rotary shaker and oscillated at approximately 70 rpm.
- Light intensity (target): 60 - 120 µE * mexp-2 * sexp-1
- Light regime: 24 hours/day light
- Light source: Fluorescent tubes, OSRAM L 36 W/11-865, cool daylight.
- Light homogeneity (target): Within ± 15 % over incubation area

EFFECT PARAMETERS MEASURED
Cell density was measured daily via Chlorophyll-a-fluorescence, excitation at 436 nm, emission at 685 nm. Dilution water was used as background signal. The pH-value at the beginning of the exposure was measured in one additional replicate of each loading level and the control. At the end of the exposure, it was measured in a pooled sample of each loading level and the control. The room temperature was measured continuously by a hygro-thermograph. Light intensity was measured prior to the start of the test.
Algae cells were evaluated microscopically at the start and the end of the incubation period. The cells were checked for unusual cell shapes, colour differences, differences in chloroplast morphology, flocculation, adherence of algae to test containers and agglutination of algal cells.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate; (SIGMA, batch number 1450864V, purity 100.3 %, CAS RN 7778-50-9)

Duration:

72 h

Dose descriptor:

EL20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The determination of the total organic carbon (TOC), carried out at the start of the exposure and at the end of the exposure, showed that there was no relationship between the nominal loading levels and the measured TOC values. Furthermore, 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.
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.

- Validity criteria is fulfilled because:
- The cell density has to increase exponentially at minimum 16-fold in the control replicates within 72 hours.
- The temperature has to be in the range of 21-24 °C at ± 2 °C. The pH-value of the control replicates should not deviate by more than 1.5 units after 72 hours.
- The mean coefficient of variation of daily specific growth rates in the control cultures during the course of the test (days 0-1, 1-2 and 2-3) must not exceed 35 %.
- The coefficient of variation of the average specific growth rates in replicate control cultures must not exceed 7 %.

Results with reference substance (positive control):

The toxicity of potassium dichromate (SIGMA, batch number 1450864V, purity 100.3 %, CAS RN 7778-50-9) to the unicellular freshwater green alga Desmodesmus subspicatus was determined over a period of 72 hours from 2012-04-10 to 2012-04-13.
The EC50 Values of the Reference Item based on nominal concentrations [mg/L], (0-72 hours) were as following:
ErC50=0.540 (95% confidence interval: 0.528-0.551)
EyC50=0.324 (95% confidence interval: 0.304-0.347)

Reported statistics and error estimates:

In this study, an ambiguous dose-response relationship was observed. Therefore, no calculation of EL-values was carried out. EL-values are given as less than or greater than indications where applicable.
The data for the tables in this report were computer generated and rounded from the full derived data for presentation. Consequently, minor deviations may occur from these figures. Calculations were carried out using the software:
- Excel, MICROSOFT CORPORATION
- SigmaPlot, SPSS INC.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2013-11-21 to 2012-11-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(23th March 2006)

Deviations:

no

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

(EC) No 761/2009 of 23 July 2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Water solubility (under test conditions): <0.02 mg/L

Analytical monitoring:

yes

Details on sampling:

Analysis of the test substance loading rates was conducted at the beginning and at the end of the exposure.
All measurements were performed in the filtered test solutions and the blank control. No measurements were performed after 24 and 48 h, since a considerably high sample volume was needed for the chemical analysis.
- Sampling method: Measured as pooled samples except for the 0 h exposure, when the stock solutions were measured

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Water accommodated fraction (WAF) approach

The test loadings were prepared by adding the respective amounts of an acetonic stock solution to empty glass vessels. After complete evaporation of the solvent, the aerated algal medium was added, moderately stirred for 96 h, followed by filtration (0.45 µm cellulose acetate membrane sterile syringe filter, VWR International). The resulting water soluble fractions (WSF) wereas used in the test.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Axenic slope culture of Desmodesmus subspicatus 86.81 SAG
- Source: Institute of Freshwater Ecology, University of Göttingen, D-37073 Göttingen, Germany

ACCLIMATION
- Culturing media and conditions (same as test): Yes

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No

Hardness:

No data

Test temperature:

22 ± 2°C

pH:

7.9-8.1

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

Nominal: 1.0, 3.2, 10, 32, 100 and 320 mg/L
Measured: <0.02 mg/L (below the quantification limit)

Details on test conditions:

TEST SYSTEM
- Test vessel: Flasks, with 100 ml of test medium, shaken (about 130 rpm)
- Type: Closed
- Material, size, headspace, fill volume: Glass, 250 mL
- Aeration: Yes
- Initial cells density: 0.50–0.85 µg/mL with respect to dry weight corresponding to about 2–5 x 10*3 cells/mL (i.e. OD680 of about 0.005 units)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: Yes

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Sterile test conditions: Yes
- Adjustment of pH: No
- Light intensity and quality: 3000 lux which corresponds to about 40 μE x m^-2 x s^-2

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: Spectrophotometer
Cell concentrations were determined every 24 h using a spectrophotometer (680 nm wavelength). Aliquots of 5 mL were removed from each test flask under sterile conditions. Cell concentrations at time 0 h were only determined in the control vessels.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study:
Loading rate (mg/l) and corresponding % inhibition average growth rate; % inhibition average yield
0 mg/L; -
1 mg/L; <10%; 11%
10 mg/L; 13%; 41%
100 mg/L; 19%; 53%

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

278 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence limits: 212-296 mg/L

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

169 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence limits: 49.3–218 mg/L

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

203 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence limits: 84.5-244 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: based on loading rate

Details on results:

- Exponential growth in the control: Yes
- Observation of abnormalities: No
- Any stimulation of growth found in any treatment: No

Results with reference substance (positive control):

No data

Reported statistics and error estimates:

Statistical analysis was performed with respect to ErCx (x= 50, 20, 10) and EyCx (x= 50, 20, 10).
Statistic: Dunnett’s Test

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

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):

Raphidocelis subcapitata (previous names: Pseudokirchneriella 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.

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1989-10-02 to 1989-10-06

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: German national standard DIN 38412, Part 9.

Deviations:

no

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

The stock solution was prepared by dissolving 1000 mg test substance and 100 mg of the solubilizer Cremophor in dilution water. The test concentrations were then prepared by dilution with test water. The test concentrations were chosen based on a range finding test.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- Test species: Scenedesmus subspicatus
- Strain: CHODAT
- Source: Algae collection Goettingen, SAG 86.81

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21.0 °C

pH:

7.18 -7.98

Nominal and measured concentrations:

- Nominal concentration: Solubilizer: Cremophor (0.10, 0.25, 0.50, 1.0, 2.5, 5.0 mg/L); Test substance: 0, 1.00, 2.50, 5.00, 10.00, 25.00, and 50.00 mg/L.
- Stock solution: 1000 mg/L
- No concentrations were measured.

Details on test conditions:

- Aeration: none
- No. of replicates: 4
- Controls: negative control, vehicle control
- Test medium: according to DIN 38412 L9
- pH during test: 7.18 - 7.98
- Temperature during test: 23.0+/-2 °C
- In vivo chlorophyll-a-fluorescence (pulsed excitation with light flashes having a wavelength of 435 nm).
- Reference substance: Potassium chromate p.a. (Merck)
- Sampling: At 0, 24, 48, 72, and 96 hours after test start, the algae cell density was determined by spectro-fluorometrical measurement using an impulse fluorometer.
- Other: The parameters pH, and temperature were determined at the end of the test. Also, at the end of the incubation period the algae cells were analyzed for signs of photosynthesis blockage by means of a spectrophotometrical scan at 300 - 780 nm. In vivo chlorophyll-a-fluorescence (pulsed excitation with light flashes having a wavelength of 435 nm).

Reference substance (positive control):

yes

Remarks:

Potassium chromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

51.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 5.00 - 122.8

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

24.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 4.72 - 564.6

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

21.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 6.58 - 68.64

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

51.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 7.93 - 204.8

Details on results:

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.

Reported statistics and error estimates:

Statistics were performed according to Tallarida RJ and Jacob LS (1979). The dose-response relation in pharmacology, 98 -103, Springer

Effect on biomass after 72 hours:
---------------------------------
EC10 = 21.3 mg/L (P95 %: 6.58 - 68.64)
EC50 = 40.3 mg/L (P95 %: 7.93 - 204.8)


Effect on growth rate after 72 hours:
-------------------------------------
EC10 = 24.8 mg/L (P95 %: 5.00 - 122.8)
EC50 = 51.6 mg/L (P95 %: 4.72 - 564.6)

Description of key information

The potential to cause toxicity to aquatic algae and cyanobacteria is assessed based on data available for Dodecyl acrylate (CAS 2156-97-0), 2-Propenoic acid, C12-14-alkyl esters (CAS 84238-60-8), 2-Propenoic acid, C16-18-alkyl esters (CAS 90530-21-5), 2-Propenoic acid, C18-22-alkyl esters (85085-17-2

 

Table 1 . Results on toxicity to algae

Ester	Method	Species	EC50/EL50 [72h]	NOEC [72h]	Reference
Dodecyl acrylate [2156-97-0]	OECD 201	Pseudokirchneriella subcapitata	>0.274 µg/L	>0.274 µg/L	BASF SE 2019
2-Propenoic acid, C12-14-alkyl esters [84238-60-8]	DIN 38412, part 9	Desmodesmus subspicatus	51.6 mg/L	-	BASF SE 1989
2-Propenoic acid, C16-18-alkyl esters [90530-21-5]	OECD 201	Desmodesmus subspicatus	278.0 mg/L	100.0 mg/L	BASF SE 2013
2-Propenoic acid, C18-22-alkyl esters [85085-17-2]	OECD 201	Desmodesmus subspicatus	100.0 mg/L	-	BASF SE 2013

 

Conclusion

The absence of a toxic potential to algae was demonstratedfor2-Propenoic acid, C16-18-alkyl esters (90530-21-5) and 2-Propenoic acid, C18-22-alkyl esters (CAS 8 0530-21-5). Nominal concentrations exceeding by far the water solubility of -Propenoic acid, C12-14-alkyl esters (CAS 84238-60-8) caused growth inhibition. It is known that these class of chemicals are forming droplets when the water solubility is exceeded. Therefore observed effects have to be interpreted as effects by direct contact with undissolved droplets and should be disregarded.2-Propenoic acid, C12-14-alkyl esters (CAS 84238-60-8) caused growth inhibition of Desmodesmus subspicatus after 72 h when tested at a nominal concentration of 51.6 mg/L, exceeding the water solubility by a factor > 100. Dodecyl acrylate (CAS 2156-97-0) did not affect the algae growth in the range of water solubility.

No toxic potential to algae in the range of water solubility was shown for longer chain acrylates. Based on this result, it can be concluded that all members of the category (C12-C22) have no toxic potential to algae.

Additional information

The toxicity of Dodecyl acrylate to the unicellular freshwater green algaPseudokirchneriella subcapitatawas 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 < 1μg/L. The study was ucted under static conditions with an initial cell density of 6442 cells/ml. One limit concentration with a loading of 1.0μg test item/L was prepared by dissolving the test item in DMF at a concentration of 20μg/ml DMF. Six replicates were used for the limit concentration, the control and solvent control.

In this study, Dodecyl acrylate did not inhibit the growth of the freshwater green algaPseudokirchneriella subcapitataafter 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 (BASF SE, 2019).

 

In a 72-hour test conducted according to (DIN 38412, part 9) the acute toxicity of 2-Propenoic acid, C12-14-alkyl esters toScenedesmus subspicatusCHODAT was examined. The EC50 and EC10-values (growth rate) were 51.6 mg/L and 24.8 mg/L, well above the water solubility limit of the substance (BASF SE, 1989).

 

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 (CAS 90530-21-5) to the green algaDesmodesmus 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 (<0.02 mg/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 artefact. 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 toDesmodesmus subspicatuswas 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 toDesmodesmus subspicatuswas 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 (all based on WAF). The no-observed-effect concentration with respect to yield (NOEyC) was 100 mg/L loading rate (WAF) (BASF SE, 2012).

 

The toxicity of the test substance2-Propenoic acid, C18-22-alkyl estersto the unicellular freshwater green algaDesmodesmus subspicatuswas 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 accommodated fraction did not include a filtration step. Hence, it cannot be excluded that particles of the test item might have caused the observed response (BASF SE, 2012).