Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-05-05 to 2010-05-06
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Qualifier:
according to
Guideline:
EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)
GLP compliance:
yes
Specific details on test material used for the study:
Batch No.: 20091203
Purity: 99.42%
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
- Test item was dispersed directly into water.
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Method of cultivation: Maintained on a continuous aeration in the laboratory at a temperature of approximately 21 °C and was used on the day of collection.
- pH: 7.1
- Suspended solids concentration: 3.9 g/L
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h
Hardness:
Approx. 140 mg/L as CaCO3
Test temperature:
21 °C ± °C
pH:
Control - 7.4 to 7.8
Test item - 7.6 to 7.7
35DCP - 7.5 to 8.1
Dissolved oxygen:
Control - 4.1 mg/L to 5.0 mg/L (initial), 1.9 mg/L to 2.0 mg/L (final)
Test item - 3.3 mg/L to 3.8 mg/L (initial), 1.5 mg/L to 1.8 mg/L (final)
35DCP - 5.7 mg/L to 7.9 mg/L (initial), 2.4 mg/L to 7.1 mg/L (final)
Salinity:
Before softening; min, typical, max concentrations:
- Na: 15.000 mg/L, 25.125 mg/L, 41.000 mg/L
- Cl: 15.200 mg/L, 22.563 mg/L, 26.8 mg/L
Nominal and measured concentrations:
Test item, nominal: 10 mg/L, 32 mg/L, 100 mg/L, 320 mg/L, 1000 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: 500 mL conical flask
- Type: Open
- No. of vessels per concentration (replicates): 1
- No. of vessels per negative control (replicates): 2
- No. of vessels per positive control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water dechlorinated by passing through an activated carbon filter and partially softened.
- Total organic carbon: 0.740 mg/L (minimum), 1.018 mg/L (typical), 1.390 mg/L (maximum)
- Particulate matter: No data
- Metals: No data on total metals
- Pesticides: 0.000 µg/L (minimum), 0.001 µg/L (average), 0.005 µg/L (maximum)
- Chlorine: 0.040 mg/L (minimum), 0.248 mg/L (average), 0.480 mg/L (maximum)
- pH: 7.16 (minimum), 7.624 (average), 7.980 (maximum)
- Ca/Mg ratio: No data
- Conductivity: 288.000 µS/cm at 20 °C (minimum), 386.192 µS/cm at 20 °C (average), 493.000 µS/cm at 20 °C (maximum)
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Light intensity: Normal laboratory lighting

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2/3.125

EVALUATION OF DATA
- In order to calculate the inhibitory effect of the test and reference items the respiration rate was expressed as a percentage of the two control respiration rates:
- The EC15, EC20, EC50 and EC80 values for the test item were determined by the inspection of the inhibition respiration rate data.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Duration:
3 h
Dose descriptor:
other: EC20
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
other: EC80
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
- Results with reference substance valid.
- Relevant effect levels:
-- EC20: 2.9 mg/L
-- EC50: 8.8 mg/L (95 % confidence limits: 6.9-11 mg/L)
-- EC80: 27 mg/L
-- NOEC: 2.4 mg/L
Reported statistics and error estimates:
- The % inhibition values were plotted against concentration for the reference item only, a line fitted using the Xfit software package (IDBS) and the EC₁₅, EC₂₀, EC₅₀ and EC₈₀ values determined from the equation for the fitted line.
- 95 % confidence limits were calculated for the reference item EC₅₀ value using the method of Litchfield and Wilcoxon (1949).
Validity criteria fulfilled:
yes
Remarks:
Met both following validity criteria: 1. That the control respiration rates were within 15 % of each other. 2. The 3 hr EC50 for 35DCP was within 5-30 mg/L.
Conclusions:
The effect of the test item on the respiration of activated sewage sludge gave a 3 hour EC50 of greater than 1000 mg/L. The NOEC after 3 hours was 1000 mg/L.

Description of key information

3 hour EC50 >1000 mg/L (OECD 209)

Key value for chemical safety assessment

EC50 for microorganisms:
1 000 mg/L

Additional information

The test substance was assessed for activated sludge respiration according to OECD Guideline 209. The effect of the test item on the respiration of activated sewage sludge gave a 3 hour EC50 of greater than 1000 mg/L. The NOEC after 3 hours was 1000 mg/L.