Octanethioic acid, S-[3-(triethoxysilyl)propyl] ester, reaction products with 2-methyl-1,3-propanediol and 3-(triethoxysilyl)-1-propanethiol

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

Study period:

17.08.2007 - 19.10.2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

adopted March 23, 2006

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment, No. 23, Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures

Version / remarks:

2000

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: Y-15821
Chemical Name: Octanethioic acid, S-[3-(triethoxysilyl)propyl]ester, reaction products with 2-methyl-1,3-propanediol and 3-(triethoxysilyl)-1-propanethiol
Batch No.: 526752
Purity: 100% (as a residue product)

Analytical monitoring:

yes

Details on sampling:

Duplicate samples from the freshly prepared test media (containing algae and without algae) of all test concentrations and from the control were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the test media of all concentrations and the control (containing algae and without algae) were taken at the end of the test (after the 72 h test period).
The concentrations of the test item, respectively its hydrolysis products, were analysed in the duplicate test media samples from all concentrations and both sampling times (0 and 72 h) of the samples without algae. From the control samples only one of the duplicate samples was analysed from each of both sampling times.

Vehicle:

no

Details on test solutions:

The highest concentration was prepared by dissolving 150 mg test item into 1500 mL culture medium. The suspensions were ultrasonic treated for 10 minutes and stirred for 24 hours in the dark at romm temperature (nominal concentration: 100 mg test item/L). Then the highest concentration were diluted with culture medium to result in a final volume of 1000 mL obtaining the following test concentrations:
Nominal: 100; 31, 9.8, 3.1; 0.95 [mg/L]
Mean measured: 70, 23.56, 8.04, 2.17, 0.67 [mg/L]

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Species: Desmodesmus subspicatus (Chodat) Hegewald et Schmidt, Strain No. 86.81 SAG
Origin: The algae were supplied by the "Sammlung von Algenkulturen, Pflanzenphysiologisches Insitut der Universität Göttingen", 37073 Göttingen, Germany.
Breeding Conditions: The algae were cultivated in the laboratories of IBACON under standardised conditions according to the test guidelines.
Reference Item: For the evaluation of the quality of the algae and the experimental conditions the reference item potassium dichromate p.A. is tested at least twice a year to demonstrate satisfactory test conditions.

Test type:

static

Water media type:

other: Reconstituted water

Limit test:

no

Total exposure duration:

72 h

Hardness:

24 mg CaCO3/L

Test temperature:

23 °C

pH:

7.9 - 8.3

Nominal and measured concentrations:

Nominal: 100; 31, 9.8, 3.1; 0.95 [mg/L]
Mean measured: 70, 23.56, 8.04, 2.17, 0.67 [mg/L]

Reference substance (positive control):

yes

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

7.1 mg/L

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

30.1 mg/L

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.11 mg/L

Basis for effect:

other: yield

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.78 mg/L

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.27 mg/L

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

1.31 mg/L

Basis for effect:

other: yield

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.67 mg/L

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.67 mg/L

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.67 mg/L

Basis for effect:

other: yield

Results with reference substance (positive control):

not specified

Reported statistics and error estimates:

yes (see table below)

Parameter (0 -72 h)  Growth rate µ [mg test item/L]  Biomass B [mg test item/L]  Yield y [mg test item/L]  72 -hours EC50 30.08   7.08  4.11  95% conf. limits 12.04 -218.33   3.83 -12.44 2.52 -6.51   72 -hours EC10  1.78 1.27  1.31   95% conf. limits 0.002 -5.98  0.16 -2.66  0.26 -2.23   72 -hours NOEC  0.67 0.67  0.67   72 -hours LOEC  2.17 2.17  2.17

Validity criteria fulfilled:

yes

Conclusions:

The influence of Y-15821 on the growth of the freshwater green algal species Desmodesmus subspicatus was assessed in a static dose-response test. The 72-hours EC50 was calculated to be 30.08 mg test item/L for growth rate, 7.08 mg test item/L for the biomass and 4.11 mg test item /L for the yield.
The overall 72-hour NOEC was determined to be 0.67 mg test item/L. The overall 72 hours LOEC was determined to be 2.17 mg test item/L.

Validity Criteria of the study:
Cell Density - Increase in Control Cultures: 160-fold increase within 72 hours, validity criterion was met.
Coefficient of Variation of Sectional (Daily) Growth Rates in Control Cultures: 25.1 %, validity criterion was met.
Coefficient of Variation of Average Growth between Control Replicates: 1.0 %, validity criterion was met.

Description of key information

The influence of Y-15821 on the growth of the freshwater green algal species Desmodesmus subspicatus was assessed in a static dose-response test. The 72-hours EC50 was calculated to be 30.08 mg test item/L for growth rate, 7.08 mg test item/L for the biomass and 4.11 mg test item /L for the yield.

The overall 72-hour NOEC was determined to be 0.67 mg test item/L. The overall 72 hours LOEC was determined to be 2.17 mg test item/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

30.08 mg/L

EC10 or NOEC for freshwater algae:

0.67 mg/L