N,N-dimethyl-3-(trimethoxysilyl)propylamine

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:

2017-05-15 to 2017-08-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline Study; EU method; GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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)

Test guideline 3

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N-dimethyl-3-(trimethoxysilyl)propylamine

EC Number:

219-786-3

EC Name:

N,N-dimethyl-3-(trimethoxysilyl)propylamine

Cas Number:

2530-86-1

Molecular formula:

C8H21NO3Si

IUPAC Name:

dimethyl[3-(trimethoxysilyl)propyl]amine

Test material form:

liquid

Details on test material:

- Name (as cited in the report): SAT 170001
- Chemical Name: N,N-dimethyl-3-(trimethoxysilyl)propylamine
- CAS No.: 2530-86-1
- Batch No.: 186020160504
- Aggregate State at RT: liquid
- Colour: colourless
- Storage Conditions: room temperature
- Expiry Date: 30.08.2017

Specific details on test material used for the study:

Name: N,N-Dimethyl-3-(trimethoxysilyl)propylamine
CAS No.: 2530-86-1
EC-No.: 219-786-3
Batch No.: 186020160504
Purity: 99.4 %
according to final report (Study number: 16-11327)
Final Report Date
(Study Number: 16-11327) :
September 14, 2016
Aggregate State at Room Temperature: Liquid
Solubility Soluble in water at tested concentration
Stability Not stable in water, after 70min complete hydrolysis/condensation is observed (Study number: 16-17622-5). Most likely primary hydrolysis product is N,N-Dimethyl-3-(trihydroxysilyl)propylamine
Colour: Colourless
Expiry Date: August 30, 2017
Storage Conditions at Test Facility:
At 20 +/- 5 °C, in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Duplicate samples from the freshly prepared test media (containing algae) of all test concentrations and from the control were taken at the start of the test.
For the determination of the TOC content of the test item and/or its hydrolysis products at the end of the test, duplicate samples from the test media of all test concentrations and the control (containing algae) were taken at the end of the test (after the 72 hours test period) by pooling together the contents of the test beakers of each treatment.

Test solutions

Vehicle:

no

Details on test solutions:

The test medium of the highest test concentration of nominal 311 mg test item/L was prepared by dissolving 310.7 mg test item into 999 mL test water by intense stirring for 23.5 hours. Adequate volumes of this test medium were diluted with test water to prepare the test media of the other desired test concentrations.
The test media were prepared just before introduction of the algae (= start of the test).

Test organisms

Test organisms (species):

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

Details on test organisms:

Species: Pseudokirchneriella subcapitata (KORSHIKOV), Strain No. 61.81 SAG, formerly known as Selenastrum capricornutum, and recently renamed as Raphidocelis subcapitata (KORSHIKOV)
Origin: The algae were supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen", 37073 Göttingen, Germany.
Breeding Conditions: The algae were cultivated in the laboratories of ibacon under standardised conditions according to the test guidelines.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

Calculated water hardness of the test water: 0.24 mmol/L (= 24 mg/L) as CaCO3

Test temperature:

23 to 24°C

pH:

8.0 at test start and 8.7 to 9.7 at test end

Nominal and measured concentrations:

The parent compound hydrolyses during the exposure period. According to stability studies in water (16-17662-5) after 70 minutes complete hydrolysis/condensation is observed. Due to the very short half-life period, the test was conducted with the mixture of reaction products and the residues of N,N-Dimethyl-3-(trimethoxysilyl)propylamine that remain after stirring of 24h. The parent compound is likely to hydrolyse mainly to N,N-Dimethyl-3-(trihydroxysilyl)propylamine. Furthermore, condensation products and polymeric species may exist. Test results are based on nominal concentration. Nominally the following concentrations were tested: 311, 100.3, 32.4, 10.4, 3.4 and 1.1 mg test item/L and a control.

Details on test conditions:

Water Temperature:
The temperature was measured daily in an Erlenmeyer flask filled with water and incubated under the same conditions as the test flasks.
Water temperature was: 23.1 to 23.8 °C
pH-Values: The pH was measured in all test item concentrations and the control at the start and the end of the test.
pH was: 8.0 at test start and 8.7 to 9.7 at test end
Light Regime: Continuous illumination
Light Intensity: The light intensity was measured once during the test at 6 positions distributed over the experimental area at the surface of the test media.
Mean light intensity: 5780 lux (range: 5230 to 6280 lux)

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 311 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 311 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 311 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 311 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

154 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

92 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 9

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

32.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 10

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Details on results:

Growth Inhibition: The 72-hour EyC50 was calculated to be > 311 mg test item/L and the ErC50 > 311 mg test item/L. The 72-hour EyC10 was calculated to be 92.0 mg test item/L and the ErC10 > 311 mg test item/L. The 72-hour NOEyC was determined to be 32.4 mg test item/L and the associated 72-hour LOEyC of 100.3 mg test item/L. The 72-hour NOErC was determined to be 32.4 mg test item/L and the associated 72-hour LOErC is 100.3 mg test item/L.
Microscopic Examination: The microscopic examination of the shape of the algal cells after 72 hours of test duration did not show any difference between the algae that had been growing up to a nominal test concentration of 311 mg test item/L and the algal cells in the control. Thus, the shape of the algal cells was not obviously affected up to this test concentration, the highest concentration tested.

Results with reference substance (positive control):

Parameter (0-72 h)
Yield [mg test item/L]
72-hour EC50 0.549
95 % conf. interval 0.490 – 0.615

72-hour EC20 0.351
95 % conf. interval 0.301 – 0.412

72-hour EC10 0.278
95 % conf. interval 0.226 – 0.341

72-hour NOEC 0.21
72-hour LOEC 0.45

Growth rate [mg test item/L]
72-hour EC50 1.12
95 % conf. interval 1.06 – 1.17

72-hour EC20 0.694
95 % conf. interval 0.646 – 0.747

72-hour EC10 0.541
95 % conf. interval 0.491 – 0.596

72-hour NOEC 0.21
72-hour LOEC 0.45

Biomass [mg test item/L]
72-hour EC50 0.567
95 % conf. interval 0.503 – 0.638

72-hour EC20 0.347
95 % conf. interval 0.295 – 0.411

72-hour EC10 0.269
95 % conf. interval 0.217 – 0.334

72-hour NOEC 0.21
72-hour LOEC 0.45

Reported statistics and error estimates:

Based on the calculated cell densities, the 72 hours ErC50 and the 72 hours EyC50 (see Definitions), the corresponding EC20 and EC10 values and where possible their 95 %-confidence limits were calculated by Probit analysis.
For the determination of the 72 hours LOEC and the 72 hours NOEC, the calculated growth rates and yields at each test concentration were tested for significant differences compared to the control values by Williams t-test.
The software used to perform the statistical analysis was ToxRat Professional, Version 3.2.1, ToxRat Solutions GmbH.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Cell Density Increase in Controls: 195.6-fold increase within 72 hours; Coefficient of Variation of Sectional (Daily) Growth Rates in Controls: 28.4 %; Coefficient of Variation of Average Growth between Control Replicates: 1.2 %

Conclusions:

The influence of N,N-Dimethyl-3-(trimethoxysilyl)propylamine on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response test on the reaction products of the test item. The 72-hour EyC50 and the 72-hour ErC50 were calculated to be nominal > 311 mg test item/L. The 72-hour NOEyC and the 72-hour NOErC were determined to be nominal 32.4 mg test item/L and the associated 72-hour LOEC were nominal 100.3 mg test item/L for yield and growth rate, respectively.

Executive summary:

Title: N,N-Dimethyl-3-(trimethoxysilyl)propylamine: Toxicity to Pseudokirchneriella subcapitata in an Algal Growth Inhibition Test

Purpose: The purpose of this test was to determine the inhibitory effect of the test item N,N-Dimethyl-3-(trimethoxysilyl)propylamine on the growth of the freshwater green algae Pseudokirchneriella subcapitata.For this purpose, exponentially growing cultures of this unicellular green 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 of application and the test system are recommended by the test guidelines and Pseudokirchneriella subcapitata is one of the recommended test species.The purpose of the analytical part of this study was to determine the content of total organic carbon (TOC) of the test item and/or its hydrolysis products in the test medium.

Guidelines/Recommendations:

OECD Guideline for Testing of Chemicals, Section 2, No. 201: "Freshwater Alga and Cyanobacteria, Growth Inhibition Test", adopted March 23, 2006, corrected July 28, 2011

Commission Regulation (EC) No 761/2009, Annex, Part C, C.3.: "Freshwater Algae and Cyanobacteria, Growth Inhibition Test", Official Journal of the European Union (EN), dated August 24, 2009

SANCO/3029/99 rev.4 11/07/00: Residues: Guidance for generating and reporting methods of analysis in support of pre-registration data requirements for Annex II (part A; Section 4) and Annex III (part A; Section 5) of directive 91/414

Material and Methods

Test Item: N,N-Dimethyl-3-(trimethoxysilyl)propylamine; Batch No.: 186020160504; purity: 99.4 %, according to final report (Study number: 16-11327).

Test Species: Pseudokirchneriella subcapitata, Strain No. 61.81 SAG formerly known as Selenastrum capricornutum, and recently renamed as Raphidocelis subcapitata (KORSHIKOV).Cultivated in the laboratories of ibacon; original source: "Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissen-schaften, Universität Göttingen", 37073 Göttingen, Germany.

Test Design: This study encompassed 7 treatment groups (6 dose rates of the test item and a control) with three replicates per test concentration and six replicates for the control. At test start 50 mL of the test concentrations were inoculated with approx. 5000 algal cells per mL test medium and defined volumes of the algal suspensions were sampled after 24, 48 and 72 hours for determination of cell densities by spectrophotometrical measurement.

Endpoints: Yield and growth rate of the algae

Test Concentrations: The parent compound hydrolyses during the exposure period. According to stability studies in water (16-17662-5) after 70 minutes complete hydrolysis/condensation is observed. Due to the very short half-life period, the test was conducted with the mixture of reaction products and the residues of N,N-Dimethyl-3-(trimethoxysilyl)propylamine that remain after stirring of 24h. The parent compound is likely to hydrolyse mainly to N,N-Dimethyl-3-(trihydroxysilyl)propylamine. Furthermore, condensation products and polymeric species may exist. Test results are based on nominal concentration. Nominally the following concentrations were tested: 311, 100.3, 32.4, 10.4, 3.4 and 1.1 mg test item/L and a control.

Test Conditions: Water temperature: 23.1 to 23.8 °C; pH values at test start 8.0, at the end of the test 8.7 to 9.7; continuous illumination; mean light intensity: 5780 lux (5230 to 6280 lux).

Analytical Determination: The quantification of the test item N,N-Dimethyl-3-(trimethoxysilyl)propylamine and/or its hydrolysis products in the test samples was performed by analysing the Total Organic Carbon content (TOC).At the start of the test 98% of the nominal carbon content of the test item and/or its hydrolysis products was found (average of the nominal concentrations of 311, 100.3, 32.4 and 10.4 mg test item/L). After 72 hours test duration, 89% of the nominal value was determined (average of the nominal concentrations of 311, 100.3, 32.4 and 10.4 mg test item/L). During the test the algae were exposed to a mean of 93% of nominal. Therefore, all reported results refer to nominal concentrations.

Conclusion: The influence of N,N-Dimethyl-3-(trimethoxysilyl)propylamine on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static concentration-response test on the reaction products of the test item. The 72-hour EyC50 and the 72-hour ErC50 were calculated to be nominal > 311 mg test item/L. The 72-hour NOEyC and the 72-hour NOErC were determined to be nominal 32.4 mg test item/L and the associated 72-hour LOEC were nominal 100.3 mg test item/L for yield and growth rate, respectively.

This study is classified acceptable and satisfies the guideline requirements for growth inhibition algae studies.