N-(3-(trimethoxysilyl)propyl)ethylenediamine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

GLP compliance:

yes

Analytical monitoring:

no

Details on test solutions:

The test substance was dissolved in double distilled water. Stock solution: 0.625 g / l

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

21.7 - 21.9°C

Nominal and measured concentrations:

Test substance concentrations of 50, 250, 125, 62.5, 31.3, 15.6 mg/l 

Details on test conditions:

Sterile 250-ml Erlenmeyer flasks with ground glass stoppers.
6 growth controls (containing the bacterial suspension)
6 control (test substance and no bacterial suspension)
3 parallel flasks for each of the 6 test concentrations (and bacterial suspension)
1 pH control for each of the 6 test concentrations (and bacterial suspension)

Reference substance (positive control):

no

Duration:

16 h

Dose descriptor:

EC10

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

67 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Table 1: Controls and test substance: pH, absorption at 432 nm, and percentage inhibition of the growth rate.

Flask	Loading rate (mg/l)	Absorption at 436 nm	% Inhibition growth rate	pH
Test substance (average of three)	500	0.034	99.0	9.4
Test substance (average of three)	250	0.062	97.4	8.4
Test substance (average of three)	125	0.243	87.0	7.6
Test substance (average of three)	62.5	0.998	43.7	7.3
Test substance (average of three)	31.3	1.529	13.3	7.2
Test substance (average of three)	15.6	1.737	1.3	7.1
Control (average of six)	-	1.760	-

 

Conclusions:

A 16hr EC50 value of 67 mg/l and EC10 value of 25 mg/l were determined for toxicity to pseudomonas putida (growth rate) in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Description of key information

Toxicity to microorganisms: 16-hour EC₅₀ 67 mg/l, EC₁₀ 25 mg/l (Pseudomonas putida, growth rate). The EC₅₀ and EC₁₀ values are equivalent to 54 mg/l and 20 mg/l respectively, when expressed in terms of the silanol hydrolysis product, N-(3-(trihydroxysilyl)propyl)ethylenediamine.

Key value for chemical safety assessment

EC50 for microorganisms:

54 mg/L

EC10 or NOEC for microorganisms:

20 mg/L

Additional information

16-hour EC₅₀ and EC₁₀ values of 67 mg/l and 25 mg/l were determined for the effects of the registration substance, N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS 1760-24-3, EC 217-164-6), on the growth rate of Pseudomonas putida in a reliable study conducted according to an appropriate test protocol (DIN 38412-8), and in compliance with GLP.

In contact with water, the submission substance hydrolyses very rapidly to form N-(3-(trihydroxysilyl)propyl)ethylenediamine and methanol.

The results may be expressed in terms of concentration of the silanol hydrolysis product, N-(3-(trihydroxysilyl)propyl)ethylenediamine, by applying a molecular weight correction: (MW of silanol = 180.28 / MW of parent = 222.36) * 67 and 25 = 54 mg/l and 20 mg/l, respectively.

Methanol does not have adverse effects on microorganisms (OECD 2004).

Reference:

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 18-20 October 2004, Methanol, CAS 67-56-1.