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Registration Dossier
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EC number: 269-056-3 | CAS number: 68186-94-7 This substance is identified in the Colour Index by Colour Index Constitution Number, C.I. 77494.
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- read-across based on grouping of substances (category approach)
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Guideline study with acceptable restrictions
- Justification for type of information:
- see attachment "Read-across justification-environ assessment-iron oxides" and “Endpoint-specific read-across justification for nano forms of iron oxide, 2021” attached in IUCLID section 13.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- GLP compliance:
- no
- Analytical monitoring:
- no
- Vehicle:
- no
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Test type:
- static
- Water media type:
- freshwater
- Limit test:
- yes
- Total exposure duration:
- 3 h
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- >= 10 000 mg/L
- Validity criteria fulfilled:
- yes
- Remarks:
- The validity of the test was checked on the basis of a graphic analysis of the reference item.
- Conclusions:
- Following the OECD Guideline 209 for triiron tetraoxide a 3-hour EC50 of >/= 10000 mg/L was obtained on activated sludge of a predominantly domestic sewage.
- Executive summary:
Following the OECD Guideline 209 for triiron tetraoxide a 3-hour EC50 of >/= 10000 mg/L was obtained on activated sludge of a predominantly domestic sewage.
A defined quantity of activated sludge is fed with a synthetic nutrition medium and the respiration rate is measured. This respiration rate is compared with those, measured in various test preparations containing different concentrations of the test item. The sensitivity of the used activated sludge is checked with 3,5-Dichlorophenol as reference item.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- read-across based on grouping of substances (category approach)
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Guideline study with acceptable restrictions
- Justification for type of information:
- see attachment "Read-across justification-environ assessment-iron oxides" and “Endpoint-specific read-across justification for nano forms of iron oxide, 2021” attached in IUCLID section 13.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
- Principles of method if other than guideline:
- read across
- GLP compliance:
- no
- Analytical monitoring:
- no
- Vehicle:
- no
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 3 h
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- >= 10 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Remarks:
- respiration rate
- Validity criteria fulfilled:
- yes
- Remarks:
- The validity of the test was checked on the basis of a graphic analysis of the reference item.
- Conclusions:
- The 3-hour EC50 was >/= 10000 mg/L on activated sludge with the test item manganese ferrite, related to respiration rate. The method used was the OECD Guideline 209.
- Executive summary:
A defined quantity of activated sludge is fed with a synthetic nutrition medium and the respiration rate is measured. This respiration rate is compared with those, measured in various test preparations containing different concentrations of the test item. The sensitivity of the used activated sludge is checked with 3,5-Dichlorophenol as reference item.
The 3-hour EC50 of manganese ferrite was >/= 10000 mg/L on activated sludge, related to respiration rate. The method used was the OECD Guideline 209.
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- read-across based on grouping of substances (category approach)
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Guideline study with acceptable restrictions
- Justification for type of information:
- see attachment "Read-across justification-environ assessment-iron oxides" and “Endpoint-specific read-across justification for nano forms of iron oxide, 2021” attached in IUCLID section 13.
- Qualifier:
- according to guideline
- Guideline:
- ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
- GLP compliance:
- no
- Analytical monitoring:
- no
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 3 h
- Remarks on exposure duration:
- Permanent aeration
- Duration:
- 3 h
- Dose descriptor:
- EC50
- Effect conc.:
- > 10 000 mg/L
- Validity criteria fulfilled:
- yes
- Remarks:
- The validity of the test was checked on the basis of a graphic analysis of the reference item.
- Conclusions:
- Following the guideline ISO 8192 a 3-hour EC50 of > 10000 mg/L for Iron(III)oxide was obtained on activated sludge of a predominantly domestic sewage.
- Executive summary:
Following the guideline ISO 8192 (Test for Inhibition of Oxygen Consumption by Activated Sludge) a 3-hour EC50 of > 10000 mg/L for Iron(III)oxide was obtained on activated sludge of a predominantly domestic sewage. Nominal concentrations of 100 mg/L, 1000 mg/L and 10000 mg/L were used. No chemical analysis was performed. The validity of the test was checked on the basis of a graphic analysis of the reference item (3,5 -Dichlorophenol).
Referenceopen allclose all
No relevant effect on activated sludge
no effect on test microorganisms
Description of key information
Applying read-across to micro- and nano-sized iron (hydr)oxides (see attachment "Read-across justification-environ assessment-iron oxides" in section 13), micro-sized iron (hydr)oxides are not considered toxic to aquatic microorganisms. Based on studies with activated sewage sludge exposed to micro- and nano-sized iron (hydr)oxides, unbounded 3-h EC50 values of >10,000 mg/L were derived, a concentration that is 10-fold above the corresponding OECD test limit.
Key value for chemical safety assessment
Additional information
For micro- and nano-sized iron (hydr)oxides, three reliable studies on toxicity to aquatic microorganisms are available. Toxicity was not observed in activated sludge exposed to micro- and nano-sized iron (hydr)oxide forms, and unbounded 3-h EC50 values of > 10 g/L were derived.
In a guideline study with activated sludge exposed to micro-sized triiron tetraoxide according to OECD 209 (Bruns, 1989), adverse effects on respiration rate were not observed after 3 h and an unbounded 3 h EC50 value of > 10 g/L was derived. Further, an unbounded 3-h EC50 value of > 10 g/L was derived for micro-sized manganese ferrite black spinel in a guideline study with activated sludge according to OECD 209.
Toxicity of nano-sized iron (hydr)oxides to aquatic microorganisms was investigated in a study using activated sludge of a predominantly domestic sewage exposed to iron hydroxide oxide/diiron trioxide (75:25) alpha nanoparticles, following ISO guideline 8192 (Test for Inhibition of Oxygen Consumption by Activated Sludge). An unbounded 3-h EC50 value of > 10 g/L was derived, as adverse effects were not observed at the highest concentration tested.
Based on read-across to micro- and nano-sized iron (hydr)oxides (see attachment "Read-across justification-environ assessment-iron oxides" in section 13), available data indicate a low potential for toxicity of iron(hydr)oxidesto activated sludge microorganisms (see table below). Toxicity ofmicro- and nano-sized iron (hydr)oxidesto aquatic microorganisms was not observed up to 10 g/L (Bruns, 1989; Bruns, 2004), a concentration that is 10-fold above the corresponding OECD test limit for toxicity to microorganisms.
Table: Toxicity of iron (hydr)oxides to aquatic microorganisms.
Endpoint | Test species | Test results | Test material/form | Reliability: Reference |
Toxicity to microorganisms | Activated sludge | EC50 (3 h): > 10 g/L nominal | triiron tetraoxide / powder | RL2: Bruns, 1989 |
. | Activated sludge | EC50 (3 h): >= 10 g/L nominal | manganese ferrite black spinel / powder | RL2: Bruns, 1989 |
. | Activated sludge | EC50 (3 h): > 10 g/L nominal | iron hydroxide oxide/diiron trioxide (75:25) / nano, alpha | RL2: Bruns, 2004 |
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