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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

activated sludge respiration inhibition testing
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
26-05-2002 to 27-05-2002
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study (OECD), validity criteria fulfilled

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:

Test material

Constituent 1
Reference substance name:
L-2-hydroxy-2-phenylacetic acid
EC Number:
EC Name:
L-2-hydroxy-2-phenylacetic acid
Cas Number:
hydroxy(phenyl)acetic acid
Details on test material:
ChiPros (R)-Mandelsäure: (R)-mandelic acid (purity: 100 %; impurities: 0.1 % mandelic acid amide)

Sampling and analysis

Analytical monitoring:

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
- preparation of inoculum: washed, conc. of dry matter: 5 g/l, aerated during the night

Study design

Test type:
Water media type:
Total exposure duration:
30 min

Test conditions

Dissolved oxygen:
- oxygen concentration during aeration: > 2.5 mg/l
- oxygen concentration immediatley before measurement: > 6.5 mg/l
- duration of measurement of oxygen consumption: 8-10 min

Details on test conditions:
- test vessel: Erlenmeyer flask (250 ml)
- test volume: 250 ml

- test assays: blank control (3x), reference substance (3x) and test substance (1000 mg/l)
- synthetic medium: 8 ml (100-fold concentrated OECD medium)
- inoculum: 50 ml (final conc. of dry matter: 1 g/l)
- dilution water: deionised water

Results and discussion

Effect concentrations
30 min
Dose descriptor:
other: EC20
Effect conc.:
> 1 000 mg/L
Nominal / measured:
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
respiration rate
Results with reference substance (positive control):
- reference substance: 3,5-dichlorophenol; EC50 is in the range of 5-30 mg/l

Any other information on results incl. tables

effect value (30 min, mg/l)
EC20: > 1000 mg/l

parameter BC (average) TS RS1 RS2 RS3
oxygen concentration (mg/l)
start 6.8-7.8 6.9 6.9 8.1 8.6
6 min 5.0-6.5 5.0 5.0 7.1 8.3

oxygen consumption rate
(mg O2/l/h) 18 19 19 10 3

specific oxygen consumption rate
(mg O2/l/h) 18 19 19 10 3

change in oxygen consumption rate compared to BC
(%) - -6 -6 44 83

before addition of inoculum (corrected)
7.1 7.6 7.2 7.3 7.0
after test end (30 min)
- 7.8 - - -
BC = blank control
RS = reference substance (reference substance conc.: RS1: 1 mg/l; RS2: 10 mg/l; RS3: 100 mg/l)
TS = test substance

effect values for reference substance (30 min, mg/l):
EC20 ca. 3.3
EC50 ca. 15
EC80 ca. 85

Applicant's summary and conclusion