2-isocyanatoethyl methacrylate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Integration und Soziales des Landes Nordrhein-Westfalen, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations: The concentrations of the test item in the test media were assessed analytically by means of liquid chromatography tandem mass spectrometry (LC-MS/MS). All test concentrations were measured at the beginning of the test (0 hours) and at the test end (72 hours).
2-Methacryloyloxyethyl isocyanate (MOI) was determined to be hydrolytically unstable under acidic, neutral and basic conditions. Urea-dimer (N,N’-[2-(2-Methyl-2-propenoic acid) ethyl ester] urea (CAS 86219-64-9; 260.3 g/mol) and aminoethylmethacrylate (129 g/mol) were detected as degradation products. Because of quick degradation of the test item, the concentrations of MOI in the test samples were determined based on the measured concentrations of N,N’-[2-(2-Methyl-2-propenoic acid) ethyl ester] urea and aminoethylmethacrylate.
- Sampling method: The degradation products were analysed in samples of all freshly prepared test solutions and control solutions at test start, and from pooled replicates per test concentration and controls at test end. The samples were analysed directly on sampling day.
- Sample storage conditions before analysis: Rest samples were frozen immediately and stored at 20°C.

Vehicle:

no

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): SAG, Culture Collection of Algae at Pflanzenphysiologisches Institut of the University at Göttingen, Göttingen, Germany, Catalog No 61.81 SAG.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21.5 - 22.0 °C

pH:

Test start: 7.64 - 7.98
Test end: 7.94 - 8.82

Nominal and measured concentrations:

Nominal: 0, 6.25, 12.5, 25, 50, 100 mg test item/L
Geometric mean measured: 0, 6.11, 12.1, 23.7, 51.3 and 97.4 mg/L (i.e. 94.9 to 102.6 % of nominal).

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL conical glass flasks coverd with air-permeable silicone-sponge caps (sterile)
- Material, size, headspace, fill volume: 250 mL conical glass flasks
- Renewal rate of test solution (frequency/flow rate): no renewal, static test
- Initial cells density: 10000 cells/mL
- Control end cells density: 192.1 x 10^4 cells/mL
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 8

GROWTH MEDIUM
- Standard medium used: yes, according to OECD 201


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: All stock solutions and the medium were prepared with purified water processed using a water purifier “Pure Lab Ultra”.
- Culture medium different from test medium: no
- Intervals of water quality measurement: Light measurements [lux] were made using a cosine (2 π) receptor (LI-189 with radiation sensor, LI-COR) each day. The test culture temperature was maintained at 22.0°C ± 2°C, and was also measured in one test vessel per day. The pH of the solutions was measured in one test vessel per test concentration, including the control, at the start of the test and in every test vessel at the end of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: yes, pH was adjusted in the growth medium to the range of 7.5 - 8.0.
- Photoperiod: continuous illumination
- Light intensity and quality: 7497 - 7596 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter (CASY 1, Model TT, Roche Diagnostics GmbH, Germany).


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 1.0, 10, 100 mg/L
- Results used to determine the conditions for the definitive study: At test end the inhibition of growth rate in the range-finder test was determined -1.1. -5.5 and 34.1 % at nominal concentrations 1.0, 10.0 and 100.0 mg/L and inhibition of yield was -5.1, -31.1 and 81.2 %, respectively.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 97.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

97.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 97.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other:

Remarks on result:

other: yield

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: 2.42 mg/L (growth rate)
- Other: The sensitivity of the test organism is routinely checked using 3,5-dichlorophenol as primary standard following internal SOPs. The tests are conducted as non-GLP studies according to the OECD guideline 201. The nominal ErC50 value of 2.42 mg/L (95% confidence limits 1.95 – 3.03 mg/L) is in good agreement with the results of an international ring test with ErC50 of 3.38 ± 1.30 mg/L.

Reported statistics and error estimates:

- Yield data showing inhibitions around 50% was statistically analysed to determine an EC50, EC20 and EC10 values together with 95% confidence intervals using Probit-analysis [6] assuming log-normal distribution of the values. Individual replicate responses were used for the regression analysis. Due to the effects on growth rate below 50 %, the ECx values could not be determined.
- The NOEC and LOEC values for growth rate and yield were determined using the Williams t-test.
- The computer program ToxRat Professional was used for all statistical evaluations.

Description of key information

ErC50 (72 h) > 97.4 mg/L (mean measured) for Pseudokirchneriella subcapitata (according to OECD 201)
NOErC (72 h) = 97.4 mg/L (mean measured) for Pseudokirchneriella subcapitata (according to OECD 201)

Additional information

The acute toxicity of 2 -isocyanatoethyl methacrylate (MOI) to algae was tested in a study conducted by Showa Denko (2013), using Pseudokirchneriella subcapitata as test species. This static dose-response test was carried out according to the OECD-Guideline 201 under GLP-conditions over a period of 72 h. The nominal test concentrations used were 0, 6.25, 12.5, 25.0, 50.0 and 100 mg/L corresponding to mean measured concentrations of 0, 6.11, 12.1, 23.7, 51.3 and 97.4 mg/L. The resulting LC50 was >97.4 mg/L (geometric mean measured), the NOEC was 97.4 mg/L (geometric mean measured).