3-[(2,2-Dimethyl-1,2-azasilolidin-1-yl)(dimethyl)silyl]-1-propanamine

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)

Rationale for reliability incl. deficiencies:

other: OECD Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

CAS No.:388606-32-4
Batch No.: YH00701
Chemical name: 1-[(3-Aminopropyl)dimethylsilyl]-2,2dimethyl-1-aza-2-silacyclopentan
Purpose: industrial chemical
Colour: colourless to yellowish
Physical state: liquid
Storage: at room temperature, protected from light and humidity
Safety precautions: Routine hygienic procedures were sufficient
to assure personnel health and safety

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

The samples were analysed directly. Approximately 60 mg test item were dissolved in 500 mL test water and stirred for approximately 24 h to obtain fortified samples at the level of 120 mg/L. Appropriate amounts of this fortified sample were diluted with test water to obtain further fortified samples at a concentration of 12 and 3 mg/L. Exact data were documented in the raw data.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

The algae were supplied by the "Sammlung von Algenkulturen, Pflanzenphysiologisches Institut der Universität Göttingen", 37073 G6ttingen, Germany. The algae were cultivated in the laboratories under standardised conditions according to the test guidelines. For the evaluation of the quality of the algae and the experimental conditions the substance potassium dichromate p.A. is tested at least twice a year to demonstrate satisfactory test conditions.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72

Post exposure observation period:

none reported

Test conditions

Hardness:

0.24 mmol/L (= 24 mg/L) as CaC03

Test temperature:

23 °C, with a maximum deviation of± 2 °C.

pH:

pH 8.1 to 8.3 at test start
pH 7.8 to 10.2 at test end

Dissolved oxygen:

not given in the report

Salinity:

not applicable

Nominal and measured concentrations:

120,37.50, 11.72,3.66, 1.14 mg test item/L, and a control.

Details on test conditions:

The test was performed with three replicates per test concentration and six replicates in the control. Volumes of 50 mL algal suspension per replicate were continuously stirred by magnetic stirrers in 50 mL Erlenmeyer flasks. They were covered with glass dishes. The flasks were incubated in a water bath. Additionally, one replicate per test concentration was prepared without algae to provide as "blank" for the spectrophotometrical measurements. The additional replicates were incubated under the same conditions as described above. The blank values were subtracted from the absorption measured in the samples containing algae in order to eliminate absorption caused by test item.

Continuous illumination. 4440 - 8880 Lux, with a maximum deviation of± 15 %.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

78.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 26.1 - 124.2

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: > 100.0

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.66 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.66 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

During the test period test item concentrations were measured in the range from 97 % to 110 % of the nominal values. Under the test conditions the test item was sufficiently stable during the test period of 72 hours. Therefore, all reported results are related to nominal concentrations of the test item.

Reported statistics and error estimates:

The experiment is valid because
- The cell density in the control cultures increased by a factor of 217 within 72 hours.
-The coefficient of variation on the sectional (daily) growth rates in the control cultures during the course of the test was 26.2 %.
- The coefficient of variation of average growth in replicate control cultures was 1.5 %.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-hour EC 50 was 78.1 mg test item/L for biomass and above 100.0 mg test item/L for the growth rate. The EC 10 values were calculated to be 39.2 and 55.5 mg test item/L for the biomass and growth rate, respectively. The 72-hour NOEC was determined to be 3.66 mg test item/L. The 72-hour LOEC was determined to be 11.72 mg test item/L.

Executive summary:

The purpose of this test was to determine the inhibitory effect of the hydrolysis products of the test item Silazan on the growth of the freshwater green algal species Desmodesmus subspicatus according to OECD Guideline 201. Exponentially growing cultures of this unicellular algal species were exposed to various concentrations of the test item under defined conditions. The inhibition of growth in relation to control cultures was determined over a test period of 72 hours, and thus over several algal generations. The test method and the test species Desmodesmus subspicatus are recommended by the test guidelines. Test concentrations of 120,37.50, 11.72,3.66, 1.14 mg test item/L, and a control were used. The 72-hour EC 50 was 78.1 mg test item/L for biomass and above 100.0 mg test item/L for the growth rate. The EC 10 values were calculated to be 39.2 and 55.5 mg test item/L for the biomass and growth rate, respectively. The 72-hour NOEC was determined to be 3.66 mg test item/L. The 72-hour LOEC was determined to be 11.72 mg test item/L.