Silicic acid, potassium salt

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

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

Principles of method if other than guideline:

Method: other: growth inhibition test; Umweltbundesamt, Berlin: Bewertung wassergefaehrdender Stoffe. Erarbeitet von der ad-hoc-Arbeitsgruppe 1 "Bewertung wassergefaehrdender Stoffe"

GLP compliance:

yes

Remarks:

TNO Division of Technology for Society, Delft, The Netherlands

Analytical monitoring:

no

Test organisms (species):

Pseudomonas putida

Details on test conditions:

Type: aquatic

Duration:

18 h

Dose descriptor:

EC0

Effect conc.:

> 3 480 mg/L

Basis for effect:

growth inhibition

Remarks on result:

other: for neutralised concentrations (pH 7.6-7.8)

Duration:

18 h

Dose descriptor:

EC0

Effect conc.:

> 348 mg/L

Basis for effect:

growth inhibition

Remarks on result:

other: for unneutralised concentrations (pH>9)

RESULTS EXPOSED:
- Nominal/measured concentrations: Not reported
- EC0 (toxicity threshold): > 10000 mg/l for neutralised
concentrations (pH 7.6-7.8). Equivalent to >3480 mg active
matter/l. 
- EC0 (toxicity threshold): > 1000 mg/l for unneutralised
concentrations (pH > 9). Equivalent to > 348 mg active
matter/l.
RESULTS CONTROL: No effects
RESULTS TEST WITH REFERENCE SUBSTANCE: No reference
substance was tested

Reference 2

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study, but no information on purity of test substance.

Principles of method if other than guideline:

Method: other: DIN 38412, Teil 27 (Bacterial oxygen consumption test)

GLP compliance:

yes

Remarks:

Henkel KGaA, Forschung Biologie Ökologie.

Test organisms (species):

Pseudomonas putida

Duration:

30 min

Dose descriptor:

EC0

Effect conc.:

3 454 mg/L

RESULTS: EXPOSED
- Nominal concentrations: 10000 mg product/l 
- Effect data (Immobilisation): EC0 10000 mg product/l (3454
mg active matter/l) (pH 11.1, at start 8.0), oxygen
consumption was reduced by 8.13% i.e.  10%
- Concentration / response curve: not reported
- Cumulative immobilisation: not reported
- Effect concentration vs. test substance solubility: not
reported
- Other effects: not reported
RESULTS CONTROL: not reported
RESULTS: TEST WITH REFERENCE SUBSTANCE
- Concentrations: not reported
- Results: not reported

Reference 3

Endpoint:

toxicity to microorganisms

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

Refer to category justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Duration:

18 h

Dose descriptor:

EC0

Effect conc.:

> 3 480 mg/L

Basis for effect:

growth inhibition

Remarks on result:

other: for neutralised concentrations (pH 7.6-7.8)

Remarks:

Source, key, 1344-09-8, Hanstveit 1989

Duration:

18 h

Dose descriptor:

EC0

Effect conc.:

> 348 mg/L

Basis for effect:

growth inhibition

Remarks on result:

other: for unneutralised concentrations (pH>9)

Remarks:

Source, key, 1344-09-8, Hanstveit 1989

Duration:

30 min

Dose descriptor:

EC0

Effect conc.:

3 454 mg/L

Remarks on result:

other:

Remarks:

Source, key, 1344-09-8, Kirch 1993

Description of key information

EC0 (18h, growth inhibition) > 10000 mg/L for neutralized concentrations (pH 7.6-7.8). Equivalent to > 3480 mg active matter/L (Pseudomonas putida)
EC0 (18h, growth inhibition) > 1000 mg/L for unneutralised concentrations (pH > 9). Equivalent to > 348 mg active matter/L (Pseudomonas putida)
EC0 (30min, oxygen consumption inhibition) 3454 mg/L

Additional information

No study available on potassium silicate. Data are read-across to sodium silicate. The toxicity of a sodium silicate solution (MR 3.46, 34.8 wt%) has been determined with a growth inhibition test in compliance with German standards and GLP using the bacterium Pseudomonas putida (Hanstveit 1989). The 18 h toxicity threshold (EC10, 10 % inhibition) of a neutralised silicate solution of pH 7.6 - 7.8 was > 3480 mg active matter/L, the highest concentration tested, while for the unneutralised solution (pH 7.9 - 10.4) effects were found at concentrations above 348 mg active matter/L. In a further GLP guideline study complying with German standards corresponding to OECD 209, the toxicity to Pseudomonas putida was tested in an oxygen consumption inhibition test. Concentrations of a sodium silicate solution (MR 3.0, 34.54 wt%) of up to 3454 mg active matter/L at pH 8.0 - 11.1 did not cause toxic effects (Kirch 1993).