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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant, guideline study available as an unpublished report. No restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
GLP compliance:
yes (incl. QA statement)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Diamminedichloropalladium
- Molecular formula (if other than submission substance): C12H6N2Pd
- Molecular weight (if other than submission substance): 211.39 g/mol
- Physical state: Yellow powder
- Analytical purity: >99.5%
- Composition of test material, percentage of components: 50.33% palladium
- Lot/batch No.: 11011
- Expiration date of the lot/batch: 31 October 2012
- Storage condition of test material: Closed dry vessel at room temperature

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant D-67435 NW-Lachen-Speyerdorf and aerated during transport. Upon arrival at the test facility the sludge was filtered, washed with tap water and resuspended in tap water. The activated sludge was aerated until usage and fed daily with 50mL/L synthetic sewage feed.

Study design

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

Test conditions

Hardness:
1.08 mmol/L
Test temperature:
Pre-test: 19.1 - 20.8°C
Main study: 19.7 - 20.8°C
pH:
Pre-test: 6.25 - 8.25 at end of test
Main study: 7.6 - 8.0 at end of test
Dissolved oxygen:
Not reported
Salinity:
Not relevant
Nominal and measured concentrations:
Pre-test: Nominal Control, 1, 10, 100 and 100 mg/L
Main study: Nominal Control, 10, 20, 30, 60, 100 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Beaker
- Material, size, headspace, fill volume: Glass containing 500 mL test solution, nutrient solution and inoculum
- Aeration: purified air through pasteur pipette at 0.75L/min flow rate
- No. of vessels per concentration (replicates): Pre-test: 1 per test item concentration except highest contentration (5 replicates); Main study: 5 per test item concentration
- No. of vessels per control (replicates): Pre-test: 6 Control, 4 positive control; Main study: 6 Control, 4 positive control
- Biomass loading rate: Pre-test: 1.08g suspended solids/L; Main-study: 1.35 g suspended solids/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap water

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : oxygen consumption

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Range finding study: yes
- Test concentrations: 0, 10, 100, 1000 mg/L
- Results used to determine the conditions for the definitive study: -4.2% inhibition at 1 mg/L, -0.6% inhibition at 10 mg/L, 81.7% inhibition at 100 mg/L, 100% inhibition at 1000 mg/L
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
29 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
Diamminedichloropalladium
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: 95% CL 28 - 30 mg/L
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
61 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
Diamminedichloropalladium
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: 95% CL 59 - 63 mg/L
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
18 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
Diamminedichloropalladium
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Key result
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
14 590 µg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
3-hour EC50 8.8 mg/L (95% CL 5.0 - 13 mg/L) which lies within the recommended range of 2- 25 mg/L.
Reported statistics and error estimates:
Oxygen consumption was calculated using linear regression.
EC50 was calculated using linear fit on a probability-logarithmic scale using Origin™ software.
NOEC was determined by testing equality of variance using and t-test or WEIR test.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 3-hour EC10 is 29 mg DDP/L (95% CL 28 - 30 mg/L). The 3-hour EC50 is 61 mg DDP/L (95% CL 59 - 63 mg/L). The NOEC is 18 mg DDP/L. This corresponds to 14.6 µg Pd L-1, 30.7 µg Pd L-1 and 9.1 µg Pd L-1, respectively.
Executive summary:

A GLP compliant, OECD guideline study to assess the inhibition of respiration of activated sludge was carried out (LAUS 2012). The study is considered to be suitable for use as the key study for this endpoint.