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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From April 23rd to 26th, 2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report Date:
2001

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
1984
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h

Test conditions

Test temperature:
19-20 °C
pH:
8.2-8.7 (test item)
8-8.7 (control)
Dissolved oxygen:
7.2-8.1 mg/l
7.4-8 mg/l
Nominal and measured concentrations:
Nominal concentrations: 10, 32, 100, 320, 1000 mg/l
Details on test conditions:
Continuous aeration during 3-h test period.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol at 5, 16 and 50 mg/l

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Details on results:
Up to 1000 mg/l, test item had no significant inhibitory effect (< 15 %) on the respiration rate of activated sludge after the incubation period of 3 hours. Based ont the physical appearance of test suspensions. the saturation concentration (equilibrium) under test conditions was < 10 mg/l and resulted in less than 15 % inhibition after 3 hours contact time. Thus, EC50 is higher than the water solubility limit of test itme, or higher then nominal 1000 mg/l; NOECof test item was at least at the limit of water solubility or at least at nominal 1000 mg/l.
Results with reference substance (positive control):
Test results confirmed the suitability of the activated sludge and method used.

Applicant's summary and conclusion

Conclusions:
NOEC (3h) = 1000 mg/l (nominal concentration)