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Ecotoxicological information

Toxicity to microorganisms

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Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
April 1984
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Version / remarks:
Commission Directive 88/302/EEC
Deviations:
no
Qualifier:
according to
Guideline:
ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)
Version / remarks:
1986
Deviations:
no
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge, domestic
Details on inoculum:
activated sludge from a lab-scale waste-water treatment system operated with municipal waste water
Test type:
static
Water media type:
freshwater
Total exposure duration:
30 min
Remarks on exposure duration:
The contact time of 30 minutes is regarded as sufficient since the test material has a high water solubility (> 500 g/L)
Nominal and measured concentrations:
nominal: 1000, 500 and 100 mg/L
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Key result
Duration:
30 min
Dose descriptor:
EC10
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Duration:
30 min
Dose descriptor:
EC0
Effect conc.:
>= 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Details on results:
The test material had no effect on the respiration of domestic activated sludge after an incubation time of 30 minutes.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC50 = 14 mg/L
Validity criteria fulfilled:
not applicable
Conclusions:
The test material was not toxic to activated sludge bacteria ( EC10 > 1000 mg/L).
Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable study report which meets basic scientific principles
Qualifier:
no guideline followed
Principles of method if other than guideline:
The test was performed according to the specification described in Liu, D. (1989): A rapid and simple method for direct determination of chemical toxicity; Toxicity Assessment 4:399-404.
Principle of the method: determination of microbial dehydrogenase activity by photometric mesurement of the reduction of resazurin at 601 nm
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge, domestic
Test type:
not specified
Water media type:
freshwater
Limit test:
no
Total exposure duration:
180 min
Test temperature:
room temperature
pH:
7.0
Nominal and measured concentrations:
nominal: 0 (control), 100, 500, and 1000 mg/L
Details on test conditions:
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per abiotic control /replicates): 2


OTHER TEST CONDITIONS
- Adjustment of pH: yes (pH 7.0), at test start

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : dehydrogenase activity, 0, 10, 20 and 30 min
Reference substance (positive control):
no
Key result
Duration:
180 min
Dose descriptor:
IC10
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: dehydrogenase activity

Extinction (601 nm)

Time (min)

BW

PK1

PK2

PC1

PC2

TA1

TA4

TA2

TA5

TA3

TA6

0

1.585

1.014

0.998

1.575

1.560

1.162

1.102

0.983

0.986

0.973

0.884

10

1.598

0.654

0.624

1.569

1.561

0.832

0.805

0.642

0.628

0.620

0.574

20

1.597

0.416

0.382

1.569

1.562

0.642

0.609

0.426

0.413

0.391

0.349

30

1.601

0.279

0.257

1.572

1.564

0.474

0.439

0.295

0.295

0.264

0.243

Activity (mU/mg dry weight)

--

512

516

--

--

479

461

480

481

494

446

Inhibition (%)

 

 

 

 

 

8.6

6.5

8.6

BW = blank control, PK = control (0 mg/L), PC = abiotic control (physical-chemical reduction), TA1+TA4 = 1000 mg /L, TA2+TA5 = 500 mg/L, TA3 + TA6 = 100 mg/L

Validity criteria fulfilled:
not specified

Description of key information

Toxicity to microorganisms: not toxic to microorganisms: EC10 >1000 mg/L (OECD 209, activated sludge respiration inhibition test; dehydrogenase test), EC10 > 10000 mg/L (DIN 38412, Pseudomonas putida test)

Key value for chemical safety assessment

Additional information

Value used for CSA: EC10/LC10 or NOEC for microorganisms: >1000 mg/L