2-Propenoic acid, 2-isocyanatoethyl 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

Study period:

The experimental start and completion dates of the study were 8 June 2007 and 22 April 2008, respectively.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Remarks:

from MHRA (UK GLP Monitoring authority)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

482-140-6

EC Name:

-

Cas Number:

13641-96-8

Molecular formula:

Hill formula: C6 H7 N O3 CAS formula: C6 H7 N O3

IUPAC Name:

2-isocyanatoethyl prop-2-enoate

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance (20 mg) was dispersed in OECD medium (2 L) in a volumetric flask. The contents of the flask were shaken vigorously before being made up to volume and then used directly at the highest test concentration (10 mg/L) or further diluted to provide the test media at the remaining lower concentrations of 0.427, 0.939, 2.07 and 4.55 mg/L.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Pseudokirchneriella subcapitata, Strain No. CCAP 278/4.
- Source: Axenic, uni-cellular, liquid slope cultures of algae were obtained for the definitive test from the Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd., Dunstaffnage Marine Laboratory, Dunbeg, Oban, Argyll, Scotland
- Age of inoculum (at test initiation): 3 days

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21.2 - 23.4°C.

pH:

7.48 - 8.39

Nominal and measured concentrations:

Nominal concentrations: 0.427, 0.939, 2.07, 4.55 and 10 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, fill volume: Conical flasks (250 ml) each containing control or test culture (100 mL)
- Initial cells density: 1 x 10E4 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6 (plus two additional flasks at 0.427 and 10 mg/L and one additional flask at 0.939, 2.07 and 4.55 mg/L. These additional flasks contained test medium but no algal cells and were used for chemical analysis.)


GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: continuous illumination
- Light intensity and quality: approximately 7186 to 7228 lux provided by 6 x 30 W “cool white” metre fluorescent tubes.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: The cell densities measured using a Coulter Z Series Particle Count and Size Analyser

TEST CONCENTRATIONS
- Results used to determine the conditions for the definitive study:
The study comprised of two range finding tests, an analytical trial and a definitive test, which employed five test concentrations, plus a dilution medium control group.

In the first range finding test, AOI was dissolved in dimethyl formamide (DMF) before its addition to inoculated OECD medium and employed nominal concentrations of 0.1, 1 and 10 mg/L. After 72 hours, algal growth was substantially inhibited at 10 mg/L and showed significant growth at 0.1 and 1 mg/l. On this occasion of analysis, the result obtained for the procedural recovery sample was acceptable (92%) so the results of analysis for test samples have been quoted; they confirmed that AOI was very unstable in water, with measured levels of between 43 and 68% of nominal approximately 30 minutes after AOI was added to water. An analytical trial was performed at 10 mg/L to estimate the rate at which AOI degraded to AOID after its addition (as a solvent spike) to OECD medium. Analysis of samples of the test medium, taken approximately one, 24 and 72 hours after dosing, gave estimated measured AOID levels of between 1.74 and 2.04 mg/l. These results confirmed that AOI was very unstable in water and that it was not possible to achieve or maintain the exposure concentration of the parent material. In terms of AOID, these results verified that a stable level of the degradation product was formed within approximately one hour of adding AOI to OECD medium.

Following a review of the data, the results of the first range finding test where the algae had been placed in the test vessels before the test substance was added, were considered unrealistic because of the highly unstable nature of AOI following its addition to OECD medium. Consequently, it was decided to follow the guidance given in OECD Monograph Number 23 for the testing of unstable compounds. As the test substance had a half-life of
less than one hour, the test substance was allowed to degrade after its addition to water before the algae were added.

The second range finding test was conducted without the use of a solvent at 1 and 10 mg/L and the algae were added to OECD medium approximately one hour after the test substance was formulated in OECD medium. After 72 hours, however, similar results were obtained to those in the first test, with growth at 1 mg/L and substantial inhibition at 10 mg/L. Based on this result, the definitive test was conducted at nominal concentrations of 0.427, 0.939, 2.07, 4.55 and 10 mg/l. No attempts were made to minimise the time between adding the test substance to OECD medium and the exposure of the test organism because AOI was known to react rapidly when added to water. The time between addition of the test substance to OECD medium and the addition of the algal cells was approximately two hours.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

7.58 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.939 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.78 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Any other information on results incl. tables

After 72 hours of exposure to AOI, the EbC50 and ErC50, respectively were 2.78 and 7.58 mg/L. The “no observed effect concentration” (NOEC) for area under the growth curve was not identified in the definitive test (<0.427 mg/L) and for growth rate was 0.939 mg/L.