N-[3-(trimethoxysilyl)propyl]butylamine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Remarks:

Inhibition control of a ready biodegradability study.

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data based on the inhibition control of a ready biodegradability study. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2012).

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Initial test substance concentration: 45 mg / 1500 mL
- Medium: 10 ml of solution (A) is mixed with 800 ml demineralised water, 1 ml of solutions (B), (C) and (D) are added and made up to 1 litre each.
- Composition of solutions: See below. All solutions were dissolved in demineralised water and made up to 1 litre. Solution D was stabilised with one drop of concentrated HCL and made up to 1 litre.
- Solution A: 8.5g KH2PO4, 21.75g K2HPO4, 33.4g Na2HPO4x 2 H2O, 0.5g NH4Cl
- Solution B: 36.4 g CaC12*2H2O
- Solution C: 22.5 g MgSO4*7H2O
- Solution D: 0.25 g FeCl3*6H2O

Test organisms (species):

other: activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from the municipal water treatment plant Breisgauer Bucht
- Preparation of inoculum for exposure: washed twice by settling the sludge, decanting supernant and re-suspending the sludge in aerated tap water
- Concentration of sludge: 30 mg per litre
- Water filtered: no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

14 d

Details on test conditions:

TEST CONDITIONS
- Composition of medium: See below
- Test temperature: 20 - 22*c
- Suspended solids concentration: 30 mg/l activated sludge
- Continuous darkness: no


TEST SYSTEM
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: aerated until use
- Measuring equipment: Total carbon analyser TOC-5000A
- Details of trap for CO2 and volatile organics if used: Absorbtion in 0.2 M Sodium Hydroxide

SAMPLING
- Sampling frequency: Day 1, 4, 7, 11, 14, 21 and 28.
- Sampling method: TOC of 0.2 M NaOH trap analysed at intervals stated above.
- Sample storage before analysis: none

CONTROL AND BLANK SYSTEM
- Inoculum blank: no
- Abiotic sterile control: no
- Toxicity control: yes

STATISTICAL METHODS: not needed

Reference substance (positive control):

yes

Remarks:

benzoic acid, sodium salt = sodium benzoate

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

41.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Result of toxicity control from ready biodegradability test

Results with reference substance (positive control):

The reference substance sodium benzoate reached the pass levels for ready biodegradability within 4 d.

Degradation in the toxicity control was 59.7% within 14 d and 72.4% within 28 d (based on ThCO2, after acidification), so there was no inhibition of the inoculum caused by the test item.

“If in a toxicity test, containing both the test and reference substance, less than 35% degradation (based on total DOC) or less than 25% (based on total ThOD or ThCO2) occurred within 14 days, the test substance can be assumed to be inhibitory.” (OECD guideline 301).

Since 59.7% degradation occured in the toxicity control after 14 d, the substance is not toxic to aquatic microorganisms. Therefore, the test item concentration of 41.7 mg/L (recalculated based on given information in the study report), can be used as the NOEC value for the toxicity to aquatic microorganisms.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 Jul 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

1984

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Version / remarks:

1988

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Energie, Jugend, Familie und Gesundheit, Wiesbaden, Germany

Analytical monitoring:

no

Details on sampling:

- Concentrations: respiration measured in all concentrations and the control
- Sampling method: For the measurement of the respiration rate a well-mixed sample was poured into a Karlsruher flask after exactly 3 h incubation. The oxygen concentration was measured with an oxygen electrode (ECM-multi, Dr. Lange, Germany), and was recorded for 10 min. Samples were continuously stirred on a magnetic stirrer during measurement. The oxygen consumption (in mg O2 L^-1 min^-1) was determined from the most linear part of the respiration curve.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test substance was directly weighed into the test flasks and flasks were filled each with 284 mL tap water.
- Differential loading: yes

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: sewage plant Gross-Zimmern, Germany
- Preparation of inoculum for exposure: An aliquot of the sludge suspension was weighed, dried and the ratio of wet sludge (g) to its dry weight (g) was determined. On this basis, aliquots of washed sludge suspension, corresponding to 3.1 g dry material per litre, were made up with tap water. To this mixture, 50 mL synthetic sewage feed per litre was added, starting two days prior to use, and the sludge was kept at room temperature under continuous aeration until use.
- Pretreatment: Sludge was washed twice with tap water by centrifugation.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

19 - 20 °C

pH:

7.6 - 8.3

Dissolved oxygen:

5.6 - 8.5 mg/L

Nominal and measured concentrations:

0 (control), 10, 32, 100, 320, 1000 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: 1 L glass flasks and 250 mL Karlsruher flasks
- Fill volume: 500 mL
- Aeration: with compressed air (approx. 0.6 L/min)
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 2
- Nutrients provided for bacteria: 16 mL/L synthetic sewage feed (16 g peptone, 11 g meat extract, 3 g urea, 0.7 g NaCl, 0.4 g CaCl2x2H2O, 0.2 g MgSO4x7H2O, 2.8 g K2HPO4; filled up to 1 L with deionized water)
- Activated sludge concentration: 200 mL sludge in 500 mL final volume

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED: Oxygen consumption was measured at the end of the 3 h incubation time.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

203 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Results with reference substance (positive control):

- Results with reference substance valid: yes
- Relevant effect levels: EC50 (3 h) = 18 mg/L (% inhibition was 14.1, 91.2 and 96.7 at 10, 32, 100 mg/L respectively )

BIOLOGICAL RESULTS:

Table 1: Oxygen consumption and inhibition of activated sludge by the test substance.

Concentration [mg/L]	Oxygen consumption [mg 02/L min]	Inhibition %
control	0.739
1000	0.459	37.9
320	0.764	-3.4
100	0.661	10.5
32	0.804	-8.8
10	0.696	5.9

VALIDITY CRITERIA:

- The respiration rates of the two controls did not differ by more than 15 %.

- The 3-hour EC 50 of the reference substance 3,5- Dichlorophenol was 18 mg/L and thus in the range of 5 to 30 mg/L for the used activated sludge batch.

- The concentration of dissolved oxygen did not drop below 2.5 mg/L during the incubation period, and just before the measurements of the respiration rates the oxygen concentra­tions were at least 6.4 mg/L.

.

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Conclusions:

No effects caused by the substance to activated sludge were determined in a 3 h exposure study, resulting in an EC50 > 1000 mg/L.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to the analogue approach justification provided in section 13.

Reason / purpose for cross-reference:

read-across source

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

203 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Conclusions:

No effects caused by the substance to activated sludge were determined in a 3 h exposure study, resulting in an EC50 > 1000 mg/L.

Description of key information

(3 h) EC50 > 1000 mg/L (nominal, OECD 209, read across from CAS No. 3068-78-8)

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

Additional information

There is no study available on the toxicity towards microorganism for N-[3-(trimethoxysilyl)propyl]butylamine (CAS No. 31024-56-3) according to OECD guideline 209, therefore good quality data for the analogue substance N-[3-(trimethoxysilyl)propylcyclohexylamine] (CAS No. 3068-78-8) was read across. Both substances share comparable silanol hydrolysis products, N-[3-(trihydroxysilyl)propyl]butylamine (target) and N-[3-(trihydroxysilyl)propylcyclohexylamine] (source). The other hydrolysis product is methanol, which does not have adverse effects on microorganisms (OECD SIDS, 2004). Additional information is given in a analogue justification attached in Section 13.2 of the IUCLID.

The available study investigates the toxicity of the source substance N-[3-(trimethoxysilyl)propylcyclohexylamine] (CAS No. 3068-78-8) to activated sludge microorganisms and was performed according to OECD guideline 209 and GLP criteria. Activated sludge from a domestic sewage treatment plant was exposed to nominal concentrations of 10, 32, 100, 320 and 1000 mg test item/L for 3 h. Since the substance is expected to hydrolyse rapidly in contact with water, the results from this study refer partly to effects of the hydrolysis products N-[3-(trihydroxysilyl)propylcyclohexylamine] and methanol. After an exposure time of 3 h an inhibition of respiration of 37.9% was recorded in the highest concentration tested, resulting in an EC20 (3 h) = 203 mg/L and EC50 (3 h) > 1000 mg/L (nominal). Based on the results with the source substance, the target substance N-[3-(trimethoxysilyl)propyl]butylamine (CAS No. 31024-56-3) is not expected to have inhibitory effects on aquatic microorganisms.

This assessment is supported by showing no inhibitory effects in a toxicity control, which was run in the ready biodegradation study according to OECD guideline 301 B on the registered substance. A substance can be assumed to be "not inhibitory" to aquatic microorganisms, if in the toxicity control of a ready biodegradation test, more than 25% degradation based on CO2 evolution (CO2/ThCO2) occurred within 14 d (OECD guideline 301). The test includes a toxicity control with a concentration of 41.7 mg/L test item and 34.3 mg/L sodium benzoate. The toxicity control attained 59.7% degradation within 14 d and 72.4% within 28 d (after acidification), based on CO2 -evolution. Therefore, the substance is not toxic to aquatic microorganisms.

References:

OECD, 2004: SIDS Initial Assessment Report for Methanol, SIAM 19, Berlin, Germany, 19-22 October 2004, Methanol, CAS 67-56-1