Registration Dossier
Registration Dossier
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EC number: 202-425-9 | CAS number: 95-50-1
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
- Endpoint:
- activated sludge nitrification inhibition testing
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study with acceptable restrictions
- Remarks:
- Basic data given (comparable to guidelines/standards)
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- ISO 9509 (Toxicity test for assessing the inhibition of nitrification of activated sludge microorganisms)
- GLP compliance:
- not specified
- Analytical monitoring:
- yes
- Vehicle:
- not specified
- Test organisms (species):
- Nitrosomonas sp.
- Test type:
- not specified
- Water media type:
- freshwater
- Limit test:
- no
- Remarks on exposure duration:
- no data
- Details on test conditions:
- Type: other: Inhibition of N-oxidation
- Duration:
- 24 h
- Dose descriptor:
- IC50
- Effect conc.:
- 47 mg/L
- Nominal / measured:
- not specified
- Conc. based on:
- not specified
- Basis for effect:
- other: Ammonia use
- Conclusions:
- The inhibition of nitrification of Nitrosomonas bacteria exposed to 1,2 -dichlorobenzene was investigated using a method similar to ISO DIS 9509. The IC50 (24 h) amounted to 47 mg/L.
- Executive summary:
Blum & Speece (1991).
The inhibition of nitrification of Nitrosomonas bacteria exposed to 1,2 -dichlorobenzene was investigated using a method similar to ISO DIS 9509. The IC50 (24 h) amounted to 47 mg/L.
Reference
Description of key information
The inhibition of nitrification of Nitrosomonas bacteria exposed to 1,2-dichlorobenzene was investigated by Blum and Speece (1991) using a method similar to ISO DIS 9509. The IC50 (24 h) was reported as 47 mg/L.
Key value for chemical safety assessment
- EC50 for microorganisms:
- 47 mg/L
Additional information
The inhibition of nitrification of Nitrosomonas bacteria exposed to 1,2-dichlorobenzene was investigated by Blum and Speece (1991) using a method similar to ISO DIS 9509. The IC50 (24 h) was reported as 47 mg/L.
A number of additional studies (Boyles (1980), McFeters et al (1983), Ribo and Kaiser (1983))) reported lower concentrations but these are not considered as reliable as they were conducted using unsuitable test systems for the assessment of microorganisms in sewage treatment plants e.g. test organisms were marine species. Furthermore, tests with Pseudomonas putida (Bringnamm and Kuehn (1976, 1977, 1980)) are recommended to be used only in cases where no other test results are available.
Therefore the 24 h IC50 of 47 mg/L, reported by Blum and Speece (1991), has been selected as the key value for toxicity of microorganisms to 1,2 dichlorobenzene.
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