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Administrative data

Endpoint:
toxicity to microorganisms
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Published public domain study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1980

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Cell multiplication inhibition test
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
Urea
EC Number:
200-315-5
EC Name:
Urea
Cas Number:
57-13-6
IUPAC Name:
urea
Details on test material:
Urea
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
not specified
Details on sampling:
No information available

Test solutions

Vehicle:
yes
Details on test solutions:
Bacterial cultures: Test solutions were prepared in double distilled water in 300 ml Erlenmeyer flasks, stoppered with cotton-lined plastic caps.
Protozoa cultures: Test solutions were prepared in double distilled water in 300 ml Erlenmeyer flasks, stoppered with metal caps.

Test organisms

Test organisms (species):
other: Pseudomonas putida and Entosiphon sulcatum
Details on inoculum:
The flagellate protozoa; Entosiphon sulcatum. The protozoa were fed with E. coli. The test cultures were incubated at 25°C for 72 hours.
The bacterium; Pseudomonas putida. Stock cultures were kept on nutrient medium in agar slant tubes. New stock cultures were prepared weekly. The inoculated stock cultures were incubated at 25°C for 24 hours.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
No information available

Test conditions

Hardness:
No information available
Test temperature:
25°C
pH:
No information available
Dissolved oxygen:
No information available
Salinity:
No information available
Nominal and measured concentrations:
Nominal
Details on test conditions:
Inoculated bacterial test solutions were incubated at 25°C for 16 hours. After termination of the test period the extinction of the monochromatic radiation was measured.
Protozoa cultures were incubated at 25°C for 72 hours, after termination of the test period the cells were counted.
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
other: Toxicity threshold
Effect conc.:
29 mg/L
Nominal / measured:
nominal
Conc. based on:
not specified
Basis for effect:
growth inhibition
Remarks on result:
other: Entosiphon sulcatum (protozoa)
Duration:
16 h
Dose descriptor:
other: Toxicity Threshold
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Basis for effect:
growth inhibition
Remarks on result:
other: Pseudomonas putida (bacteria)
Details on results:
The 72 hour toxicity threshold of Entosiphon sulcatum to urea was 29 mg/l, and the 16 hour toxicity threshold of urea to Pseudomonas putida was > 10000 mg/l.
Results with reference substance (positive control):
Not examined
Reported statistics and error estimates:
No information available

Any other information on results incl. tables

The 72 hour toxicity threshold of Entosiphon sulcatum to urea was 29 mg/l, and the 16 hour toxicity threshold of urea to Pseudomonas putida was > 10000 mg/l.

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
The 72 hour toxicity threshold of Entosiphon sulcatum to urea was 29 mg/l, and the 16 hour toxicity threshold of urea to Pseudomonas putida was > 10000 mg/l.
Executive summary:

The 72 hour toxicity threshold of Entosiphon sulcatum to urea was 29 mg/l, and the 16 hour toxicity threshold of urea to Pseudomonas putida was > 10000 mg/l.