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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:
From Oct. 19, 2009 to Nov. 11, 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted according to standard guidelines (with GLP)
Justification for data waiving:
other:
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Glycerides, C8-18 and C18-unsatd.
EC Number:
266-946-3
EC Name:
Glycerides, C8-18 and C18-unsatd.
Cas Number:
67701-28-4
Molecular formula:
Triglycerides containing a glycerol backbone esterified to fatty acids with a carbon chain length of C8-18 as well as unsaturated C18 fatty acids
IUPAC Name:
Tri(C8-18 and C18-unsatd. fatty acyl)glycerol
Details on test material:
- Name of test material (as cited in study report): Fully hydrogenated coconut oil (CAS N° 84836-98-6, EC N° 284-283-8); under the SDA nomenclature, the name of this substance is ‘Glycerides, C8-18 and C18-unsatd.’
- Physical state: Solid (bright yellow)
- Expiration date of the lot/batch: December 26, 2009
- Storage condition of test material: In original container, at room temperature (10-30 °C), in the dark
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
No

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
Not applicable

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test item was directly dosed into each test flask and tap water was added. The mixture was stirred for about 24h at 22 °C in the dark / diffuse light.
- Eluate: Water
- Controls: 2 controls (tap water, synthetic sewage and inoculum)

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Preparation of inoculum for exposure: Washed by centrifugation and the supernatant liquid phase was decanted. The solid material was suspended in tap water and again centrifuged (the procedure was repeated 3 times). The washed sludge was re-suspended in tap-water and sewage feed (50 mL/L) was added. The sludge was kept at room temperature under continouse aeration until use overnight. The suspension was fed again on the first d.
- Initial biomass concentration: 3.8 g/L

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Remarks on exposure duration:
None

Test conditions

Test temperature:
22 °C during dissolution phase
21 - 22 °C during pre-incubation
18 - 20 °C during evaluation period
pH:
7.4 - 8.4
Dissolved oxygen:
2.5 - 7.9 mg O2/L
Nominal and measured concentrations:
10, 32, 100, 320 and 1000 mg/L (nominal)
Details on test conditions:
TEST SYSTEM
- Test vessel: Flasks and Karlsruher flasks
- Type (delete if not applicable): Closed
- Material, size, headspace, fill volume: Glass, 1L volume and 250 mL volume (Karlsruher flasks)
- Aeration: Compressed air (0.8 L/min)
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Biomass loading rate: 0.76 g/L

OTHER TEST CONDITIONS
- Adjustment of pH: No

EFFECT PARAMETERS MEASURED: Oxygen consumption, measured after 3h of incubation time

TEST CONCENTRATIONS
- Test concentrations: 10, 32, 100, 320 and 1000 mg/L (nominal)
Reference substance (positive control):
yes
Remarks:
3,5-Dicholphenol

Results and discussion

Effect concentrationsopen allclose all
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
Remarks on result:
other: None
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
Remarks on result:
other: None
Duration:
3 h
Dose descriptor:
EC10
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: None
Details on results:
- Based on measured inhibition rates, the 3h EC10, EC30 and EC50 could not be quantified because, up to the highest nonminal test concentration (1,000 mg/L), less than 10% inhibition was noted.

- The maximum deviation in respiration rates was 8% at a concentration of 100 mg/L, however, no inhibition was found at a concentration of 1000 mg/L.
Results with reference substance (positive control):
- Results with reference substance valid: Yes
- Relevant effect levels: The 3h EC50 was calculated to be 15.2 mg/L (dues to mathematical reasons, no 95% CL could be determined
Reported statistics and error estimates:
None

Any other information on results incl. tables

For more detailed information on the results, see table 1 and figure 1 in the window 'attached background material'.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the test condition, no dose related response was found in the activated sludge inhibition test with fully hydrogenated coconut oil. The 3h EC10, EC20 and EC50 were determined to be >1,000 mg/L (nominal).
Executive summary:

The influence of fully hydrogenated coconut oil on the activity of the activated sludge was evaluated by measuring the respiration rate under defined conditions. The test followed the guidelines OECD 209, EU method C.11 and EPA OPPTS 850.6800 with GLP compliance.

The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measured in the presence of variouse concentrations after an incubation period of 3h.

Three tests, one with a reference susbstance 3,5 -Dichlorophenol and two inoculum controls were run in parallel for validation purposes.

Under the test condition, no dose related response was found in the activated sludge inhibition test with fully hydrogenated coconut oil. The 3h EC10, EC20 and EC50 were determined to be >1,000 mg/L (nominal).