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Toxicity to microorganisms

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Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
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
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Duration:
16 h
Dose descriptor:
EC50
Effect conc.:
67 mg/L
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.
Endpoint:
toxicity to microorganisms
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 attached justification for grouping of substances provided in IUCLID Section 13.
Reason / purpose:
read-across source
Duration:
16 h
Dose descriptor:
EC10
Effect conc.:
25 mg/L
Conc. based on:
test mat.
Basis for effect:
growth inhibition
Duration:
16 h
Dose descriptor:
EC50
Effect conc.:
67 mg/L
Conc. based on:
test mat.
Basis for effect:
growth inhibition

Description of key information

Toxicity to microorganisms: EC50 of 67 mg/l; EC10 25 mg/l (Pseudomonas putida, growth rate).

Key value for chemical safety assessment

Additional information

There are no microorganism toxicity data available for N-[3-(dimethoxymethylsilyl) -2-methylpropyl]ethylenediamine (CAS 23410-40-4), therefore good quality data for the analogue substance, N-(3-(trimethoxysilyl) propyl) ethylenediamine (CAS 1760-24-3) have been read across. Both substances share the comparable silanol hydrolysis products, N-[3-(dihydroxymethylsilyl)-2-methylpropyl]ethylenediamine and N-[3 (hydroxydimethylsilyl)propyl]ethylenediamine. It is therefore considered valid to read-across the results for N-(3-(trimethoxysilyl) propyl) ethylenediamine to fill the data gap for the registered substance. The other hydrolysis product being methanol, which does not have adverse effects on microorganisms (OECD, 2004a).

Both substances are within a wider analogue group than the analogue group discussed in Section 1.4. Substances within this wider analogue group, in general, exhibit no evidence of significant toxicity to microorganisms.

This wider analogue group for the toxicity to microorganisms endpoint consists of a number of sub-classes of substances. However, read-across is carried out between substances with the same sub-class in most cases.

Table 7.1.6 presents microorganism toxicity data available for substances within the sub-class (III-8) of substances having amino group(s) in side chain after any very rapid hydrolysis has been accounted for.Both N-[3-(dimethoxymethylsilyl) -2-methylpropyl]ethylenediamine (CAS 23410-40-4) and N-(3-(trimethoxysilyl) propyl) ethylenediamine (CAS 1760-24-3) are members of this sub-class.

Table 7.1.6. Microorganism toxicity data available for substances within the relevant sub-class (III-8) of chemicals

CAS

Name

Result: E(I)C50(mg/l)

Result: NOEC (or EC10/ EC20) (mg/l)

Guideline Number

Test method

Species

Duration

Reliability

027445-54-1

Cyclohexanamine,N-[(diethoxymethylsilyl)methyl]-

624.2 mg/l    (EC20 240.2 mg/l)

 

OECD 209

ASRI

 

3hr - but stirred 24hr

1a

003068-78-8

N-[3-(trimethoxysilyl)propylcyclohexylamine]

>1000

EC20 = 203 mg/l

OECD 209

ASRI

 

3 hr

1a

157923-74-5

2,2-dimethyl-4-(trimethoxysilyl)butylamine

>1000

EC15 869. 17.5% inhibition at 1000 mg/l.

OECD 209

ASRI

 

3 hr

1a

227085-51-0

N-ethyl-3-trimethoxysilyl-2-methylpropanamine

>1000

 

OECD 209

ASRI

 

3 hr

1a

000919-30-2

3-aminopropyltriethoxysilane

43 mg/l

EC10 13 mg/l

Huls AG method

oxygen consumption

P. putida

5.75 hr

2c

082985-35-1

Bis(trimethoxysilylpropyl)amine

estimated value, approximately 1000

220

OECD 209

ASRI

 

3 hr

1a

001760-24-3

N-(3-(trimethoxysilyl)propyl)ethylenediamine

67 mg/l

EC10 25 mg/l

DIN 38 412, Part 8 (Pseudomonascell multiplication inhibition test)

growth inhibition test

P. putida

16 hr

1c

[N,N-Bis(trimethylsilyl)aminopropyl]methyldiethoxysilane

>100

 

OECD 209

ASRI

 

3 hr

1a

None

reaction mix (reaction mass of 6 benzylated amine silanes)

569

130; EC20 172

OECD 209; EC C.11

ASRI

 

3 hr

1a

 

Additional information is given in a supporting report (PFA, 2013l) attached in Section 13 of the IUCLID dossier.

The influence of the test item N-(3-(trimethoxysilyl) propyl) ethylenediamine (CAS 1760-24-3) were determined for toxicity to Pseudomonas putida (growth rate) in a reliable study conducted according to DIN 38412/8 and GLP (Hüls AG, 1994c). The nominal test concentrations were 15.6, 31.3, 50, 62.5, 125, 250 mg/l. A 16 hr EC50 value of 67 mg/l and EC10 value of 25 mg/l was determined in a static test type.