Morpholine, 4-[(triethoxysilyl)methyl]-

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:

2007-07-12 to 2007-11-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(92/69/EWG, C.3)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

480-370-1

EC Name:

-

Cas Number:

21743-27-1

Molecular formula:

Hill formula: C11H25NO4Si CAS formula: C11H25NO4Si

IUPAC Name:

4-[(triethoxysilyl)methyl]morpholine

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

All concentrations in paralell and in duplicate at 0 and 72 h. Values available only for concentrations above LOQ

Test solutions

Vehicle:

no

Details on test solutions:

A Stock solution was prepared by dissolving 50 mg test item into 500 mL culture medium. The stock suspension was stirred for 24 hours in the dark to assure the hydrolysis of the test item. Adequat volumes of this test medium were diluted with culture medium to prepare the test media.
In the highest concentration of 32 mg/L the medium remain turbid over the complete 72 hours.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus (Chodat)
- Strain: No 86.81 SAG
- Source (laboratory, culture collection): University of Göttingen, Germany
- Method of cultivation: according to guidelines


ACCLIMATION
- 3 days

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

-

Test conditions

Hardness:

24 mg CaCO3/L

Test temperature:

23 °C

pH:

8.0 at the beginning
8.1-8.6 at the end

Dissolved oxygen:

not given

Salinity:

not given

Nominal and measured concentrations:

0.32, 1, 3.2, 10, 32 mg/L nominal
At the start of the test just before introduction of the algae 82% of the nominal test concentrations were found. After 72 hours test duration 75% of th nominal values were determined. Thus, durin the test period of 72 hours the algae were exposed to a mean of 78% of nominal. Therefore, all reproted biological results are related to the initial mean concentraions of the test item.

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks of 50 mL volume with at least 30 mL of test medium
- Initial cells density: 5000 algal cells per mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3



GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
see above


OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: no
- Photoperiod: continious
- Light intensity and quality: 6615 lux (mean)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer


TEST CONCENTRATIONS
- Range finding study
- Test concentrations: <100 mg/L

Reference substance (positive control):

yes

Remarks:

potassium dichromate at least twice a year

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

7 mg/L

Nominal / measured:

meas. (initial)

Basis for effect:

biomass

Remarks on result:

other: 6.6-7.4

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

25 mg/L

Nominal / measured:

meas. (initial)

Basis for effect:

growth rate

Remarks on result:

other: 22.0-29.1

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.9

Nominal / measured:

meas. (initial)

Basis for effect:

biomass

Remarks on result:

other: 1.7-2.1

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

6.6

Nominal / measured:

meas. (initial)

Basis for effect:

growth rate

Remarks on result:

other: 4.6-8.4

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.8 mg/L

Nominal / measured:

meas. (initial)

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.8 mg/L

Nominal / measured:

meas. (initial)

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test):
- Unusual cell shape: no
- Colour differences: not reported
- Flocculation: not reported
- Adherence to test vessels: not reported
- Aggregation of algal cells: not reported
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: yes but considered, see above
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

no details in report

Reported statistics and error estimates:

standard procedures

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-hours EC50 value was calculated to be 25.0 mg/L (NOEC: 0.8 mg/L) for the growth rate, and 7.0 mg/L (NOEC: 0.8 mg/L) for the biomass. Thus, it can be concluded that N-(Morpholinomethyl)triethoxysilan is toxic to the green algal species Desmodesmus subspicatus.

Executive summary:

The infuence of N-(Morpholinomethyl)triethoxysilane on the growth of the freshwater green algal species Desmodesmus subspicatus was assessed in a static dose-response test (OECD Guideline 201). The 72-hours EC50 value was calculated to be 25.0 mg/L (NOEC: 0.8 mg/L) for the growth rate, and 7.0 mg/L (NOEC: 0.8 mg/L) for the biomass. Thus, it can be concluded that N-(Morpholinomethyl)-triethoxysilane is harmful to the green algal species Desmodesmus subspicatus.