Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Endpoint:
activated sludge nitrification inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Data originate from ISO Standard 8192 and are based on an interlaboratory trial performed in 2004.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
not specified

Test solutions

Vehicle:
not specified
Details on test solutions:
Not specified.

Test organisms

Test organisms (species):
activated sludge
Details on inoculum:
Based on tests performed by various laboratories.

Study design

Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 min
Remarks on exposure duration:
Additional: 3 h

Test conditions

Reference substance (positive control):
not required

Results and discussion

Effect concentrationsopen allclose all
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
1.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of nitrification rate
Remarks on result:
other: 95% CL: 1.13 - 1.87 mg/L
Duration:
180 min
Dose descriptor:
EC50
Effect conc.:
3.74 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of nitrification rate
Remarks on result:
other: 95% CL: 1.87 - 5.61 mg/L

Applicant's summary and conclusion

Conclusions:
N-methylaniline inhibits nitrification processes in activated sludge at concentrations between 1 and 6 mg/L. According to the ISO Standard 8192, a range of 0.1 to 5 mg/L is considered to be the valid range for the EC50 of N-methylanilne as a reference substance for inhibition of nitrification.
Executive summary:

In an interlaboratory trial carried out in July 2004 using activated sludge from domestic sewage, data for EC50 values were collected on the inhibition of nitrification during exposure to N-methylaniline for 30 and 180 min. The results were used to determine precision data on the EC50 values and the valid ranges for the use of N-methylaniline as a reference substance. The average EC50 for 30 min. was 1.5 ( ± 0.44) mg/L and the average EC50 for 180 min. (3 h) was 3.74 (± 2.24) mg/L.