Propanoic acid, 2-hydroxy-2-methyl-, 2-propen-1-yl ester

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

Study was conducted for 3 days instead of 5.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

prop-2-en-1-yl 2-hydroxy-2-methylpropanoate

EC Number:

700-908-3

Cas Number:

19444-21-4

Molecular formula:

C7H12O3

IUPAC Name:

prop-2-en-1-yl 2-hydroxy-2-methylpropanoate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

2 samples (2 times about 30 ml per concentration and control) were taken at the start and 2 samples (2 times about 30 ml per concentration and control) at the end of exposure. Samples were taken from the freshly prepared test solutions immediately before exposure (separately prepared for analytical) and from two composite test vessels after 72 hours of exposure. All samples were kept at -18 to -22 °C until analysis.

Test solutions

Vehicle:

yes

Details on test solutions:

Control (Blank): Blank: Reconstituted water (OECD-medium)
Vehicle: 3µL DMF (dimethylformamide) in 30ml reconstituted water (OECD-medium)

Test item: 3309.2 mg of CA 2215 A were mixed and made up to 10 ml with DMF. This first stock solution was used to prepare all other stock solutions in DMF. 2.5 ml was mixed and made up to 5.0 ml to prepare stock solution 2; 2.5, 1.25, 0.625, 0.3125 and 0.15625 ml were mixed and made up to 10 ml to prepare stock solutions 3, 4, 5, 6 and 7. The test solutions were prepared by adding 3 µl from these stock solutions to 30 ml reconstituted water (OECD-medium) in the test vessels (before the algae were placed in the test vessels).

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Green Algae.
- Strain: Selenastrum capricornutum ATCC 22662 ≡ Pseudokirch Subcapitata SAG 61.81.
- Source (laboratory, culture collection): Collection of algae cultures, Pflanzenphysiologisches Institut, University, Nikolausberger Weg 180, D-3400 Göttingen, Germany.


ACCLIMATION
- Acclimation period: 3 days under test conditions.

The algae culture used was demonstrated to be adequately sensitive.

Study design

Test type:

static

Limit test:

yes

Total exposure duration:

72 h

Post exposure observation period:

None

Test conditions

Hardness:

24 mg CaCO3/L

Test temperature:

24 °C ± 1°C

pH:

Between 7.8 - 8.0 and 7.7 - 7.8 at the start and the end of exposure, respectively.

Nominal and measured concentrations:

Based on the results of the range-finding-test, the following nominal concentrations were selected for the definitive test.
32.0, 16.0, 8.0, 4.0, 2.0, 1.0 and 0.5 mg test item/L.

Th emeasured test concentrations were 28.4, 13.7, 7.7, 3.9, 1.9, 1.1 and 0.55 mg/L at the start of exposure and 29.5, 14.0, 7.1, 3.6, 1.7, 0.95 and 0.50 mg/L at the end of the exposure.

Details on test conditions:

TEST SYSTEM
- Test vessel:
100 ml Erlenmeyer flask
- Material, size, headspace, fill volume:
30ml test solution per flask.

- Initial cells density:
10600 cells/L

- Replicates:
Each test concetration was tested in 3 replicates, the blank and vehicle controls in 6.

TEST MEDIUM / WATER PARAMETERS
- Ca/mg ratio:
24 mg/CaCO3/L.
- Conductivity:
124 µS.
- Photoperiod/Light intensity and quality:
Continuous illumination, cold white fluorescent light at 117 µE/m2 (approx 800 lux).

MEASUREMENTS:
Cell densities were measuted at 24, 48 and 72 hours of exposure using CytoFluor II (a Fluorecence Multi-Well PLate Reder).
Temperature was continuosly measured.
The pH of the test solution was measured at 0h nad 72 hours of exposure.
Light intensity was mesured at the start of exposure using a Quantum Radiometer/Photometer.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: 95 % CL

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: Significant on 5% level

Details on results:

There was no statistically significant (p>0.05) difference in mean cell density between the control and the vehicle and the treatment groups with concentrations of 0.50, 1.0, 2.0 mg/L. Percent inhibition values on the basis of growth rate were 0.088, 0.00, 0.38 and 3.63 %. A statistically significant (p>0.05) difference in mean cell density was present between control and the treatment groups with concentrations of 4.0, 8.0, 16.0 and 32.0 mg/L. Percent inhibition values on the basis of growth rate were 10.67, 16.35, 30.58 and 49.97 %.
No unusual appearance of the algae cells and no flocculation, adherence to glass walls or aggregation could be observed at the end of exposure.

Applicant's summary and conclusion

Conclusions:

ErC50 (0 – 72 h) of CA 2215 A was determined to be 32.0 mg/L based on nominal concentrations.

The NOErC growth inhibition (0 – 72 h) was 2.0 mg/L based on nominal concentrations of CA 2215 A.

Executive summary:

Range-finding tests showed that the RrC50 (72h) will be between 1.0 and 10.0 mg/L. Based on the range-finding test, the following nominal concentrations of CA 2215 A were chosen for the main test: 32.0, 16.0, 8.0, 4.0, 2.0, 1.0 and 0.50 mg/L. DMF was used as solvent, not exceeding 100mg/L and with identical vehicle concentration in all test concentrations. 3309.2 mg of CA 2215 A were mixed and made up to 10 ml with DMF. This first stock solution was used to prepare all other stock solutions in DMF. The test solutions were prepared by adding 3 µl from these stock solutions to 30 ml reconstituted water (OECD-medium) in the test vessels (before the algae were placed in the test vessels). A vehicle with 3 µl DMF in 30 ml reconstituted water (OECD-medium) was used for CA 2215 A. When the algae are placed in the test vessels, the exposure starts (0 h). Exposure of Selenastrum capricornutum was started at an initial cell density of 10600 cells/L after pre-culture period of 3 days. 

In the test with CA 2215 A, the temperature was maintained constant at 24 ± 1°C. Continuous illumination with cold white fluorescent light at 117 µE/m²(approx. 8000 lux) was used. The pH of the test solutions was between 7.8 – 8.0 at the start and 7.7 – 7.8 at the end of exposure. The multiplication factor of the algae cell density in the control was 77 with 72 hours. The nominal test concentrations were: 32.0, 16.0, 8.0, 4.0, 2.0, 1.0 and 0.050 mg test item/L. 

The measured test concentrations of CA 2215 A were 28.4, 13.7, 7.7, 3.9, 1.9, 1.1 and 0.55 mg/L at the start of exposure. 

The total content of CA 2215 A was found within 85.6 – 110.0 % at test begin and 85.0 – 100.0 % at test end. 

Following calculations of EC50 and NOEC are based n nominal concentrations. 

ErC 50 (0 – 72 h):                32.0 mg/L

95% confidence limit:           28.4 – 37.0 mg/L

Slope:                                  1.121 ± 0.091

NOEC (0 – 72 h):                NOErC : 2.0 mg/L

(significant on 5% level)

 

ErC50 (0 – 72 h) of CA 2215 A was determined to be 32.0 mg/L based on nominal concentrations.

 

The NOErC growth inhibition (0 – 72 h) was 2.0 mg/L based on nominal concentrations of CA 2215 A.