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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:
12 January 2004 to 16 March 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
1984
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Specific details on test material used for the study:
The substance is the Source of the read-across.

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
The test material hydrolyses quickly (t1/2 < 3 h). Based on advice from the UK Environment Agency, the test material was ground and stirred in sterile diluent for 96 h at 21 °C to allow hydrolysis, and expose test organisms to hydrolysis products.
The organic hydrolysis products are water soluble, but the co-formed aluminium hydroxide is poorly soluble (1.5 mg/L at 20 °C), so the test material was filtered to remove solids that may have exerted a physical effect on the test organisms.

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
A mixed population of activated sewage sludge micro-organisms was obtained from the aeration stage of the Sever Trent Water PLC sewage treatment plant at Loughborough, Lecestershire, UK, which treats predominantly domestic sewage.
The activated sample was maintaine on continuous aeration at 21 °C and was used on the day of collection. pH 7.7.

Test conditions

Hardness:
100 mg CaCO3/L
Test temperature:
21 °C
pH:
7.7
Conductivity:
415.9 uS/cm.
Nominal and measured concentrations:
1000 mg/L (expressed in terms of parent test material)
Details on test conditions:
Activated sewage sludge was exposed to a saturated solution of teh hydrolyis products of the test material at a concentration of 1000 mg/L (expressed in terms of parent test material) (three replicate flasks_ for a period of 3 h at 21 °C with teh addition of a syntheic sewage as a repiratory substrate.
The rate of respiration was determined after 30 min and 3 h contact time and compared to data for the control and a reference material 3,5-dichlorophenol.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat. (dissolved fraction)
Basis for effect:
inhibition of total respiration
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat. (dissolved fraction)
Basis for effect:
inhibition of total respiration
Results with reference substance (positive control):
The reference material gave a 3 h EC50 of 12 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
3 h EC50 >1000 mg/L; NOEC 1000 mg/L.