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Ecotoxicological information

Toxicity to microorganisms

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Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Nominal and measured concentrations:
10, 32, 100, 320 and 1000 mg/L
Key result
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
Remarks:
respiration rate
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Conclusions:
The effect of uncoated nano calcium carbonate on the respiration of activated sewage sludge to microorganisms was determined to be a 3 h EC50 of greater than 1000 mg/L. The NOEC after 3 hours exposure was 1000 mg/L.
Executive summary:

The study (Youngs, 2010) was performed according to OECD Guideline 209 and in accordance with GLP. The study assessed the toxicity of calcium carbonate (nano) to activated sewage sludge at nominal test concentrations of 10, 32, 100, 320 and 1000 mg/L. No toxic effects were seen at any concentration of calcium carbonate (nano) tested. Hence, the 3 h EC50 was >1000 mg/L and the NOEC was 1000 mg/L. Calcium carbonate (nano) is therefore not toxic to aquatic microorganisms up to a concentration of 1000 mg/L. Evidence of undissolved test material was observed in some of the test vessels suggesting that the concentrations tested exceeded the maximum solubility of calcium carbonate in water.

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 section 13 for the read across justification.
Reason / purpose for cross-reference:
read-across source
Key result
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
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration

Description of key information

Based on a read-across approach, the effect of uncoated nano calcium carbonate on the respiration of activated sewage sludge to microorganisms was determined to be a 3 h EC50 of greater than 1000 mg/L. The NOEC after 3 hours exposure was 1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

No study on the toxicity of the test item to microorganisms has been conducted. The study was waived and as supporting information a read-across to uncoated nano calcium carbonate has been performed.


 


The study (Youngs, 2010) was performed according to OECD Guideline 209 and in accordance with GLP. The study assessed the toxicity of calcium carbonate (nano) to activated sewage sludge at nominal test concentrations of 10, 32, 100, 320 and 1000 mg/L. No toxic effects were seen at any concentration of calcium carbonate (nano) tested. Hence, the 3 h EC50 was >1000 mg/L and the NOEC was 1000 mg/L. Calcium carbonate (nano) is therefore not toxic to aquatic microorganisms up to a concentration of 1000 mg/L. Evidence of undissolved test material was observed in some of the test vessels suggesting that the concentrations tested exceeded the maximum solubility of calcium carbonate in water.