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Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study (non-GLP)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report date:
1991

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Undecanal
EC Number:
203-972-6
EC Name:
Undecanal
Cas Number:
112-44-7
Molecular formula:
C11H22O
IUPAC Name:
undecanal
Details on test material:
- Name of test material (as cited in study report): undecanal (ca. 65%)
- Substance type: technical product
- Physical state: liquid
- Analytical purity: ca. 65%
- Impurities (identity and concentrations): decane, undecanol, 2-methyl decanal
- Composition of test material, percentage of components:

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: test substance added directly to test assays under nitrogen atmosphere.
- Controls: positive controls (reference substance)
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not used
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms

Test organisms (species):
activated sludge, domestic
Details on inoculum:
- Laboratory culture: activated sludge from laboratory wastewater treatment plants treating  municipal sewage (K210)
- Preparation of inoculum for exposure: The inoculum was washed, brought to a concentration of 5 g/L dry substance and aerated for about 24 hours. 50 ml were added to a total volume of 250 ml to obtain a concentration of 1 g/L dry substance in the test.
- Biomass concentration: 1 g/L dry weight

Study design

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

Test conditions

Test temperature:
room temperature
Nominal and measured concentrations:
nominal: 1003, 530, 260, 125, 50 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: liquid volume: 250 mL
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 3 (reference substance)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: OECD test medium

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- dissolved oxygen: online measurement
Reference substance (positive control):
yes
Remarks:
3,5 dichlorophenol (CAS 591-35-5)

Results and discussion

Effect concentrationsopen allclose all
Duration:
3 h
Dose descriptor:
other: EC20
Effect conc.:
ca. 85 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:
EC50
Effect conc.:
ca. 300 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: EC20
Effect conc.:
ca. 55 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: The effect concentration based on the active ingredient is estimated based on the percentage of undecanal (ca. 65%) in the test material.
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
ca. 195 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: The effect concentration based on the active ingredient is estimated based on the percentage of undecanal (ca. 65%) in the test material.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: EC20 (30 min): ca. 12 mg/L; EC50 (30 min): ca. 29 mg/L; EC80 (30 min): ca. 140 mg/L

Any other information on results incl. tables

Incubation duration 3 h (180 min):

Tested concentration
(65% undecanal)

Respiration rate

Respiration change

[mg/L]

[mg O2/L/h]

[%]

blank (mean)

24

---

50*

18

20

125

10

-47

260

9

-53

530

12

-37

1003

9

-53

 

*: This test concentration was tested later than the others. The blank for this measurement had a respiration rate of 15 mg/L*h.

 

Negative values for respiration change represent inhibition while positive values represent promotion of respiration.

 

Tested concentration (reference substance)

Respiration rate

Respiration inhibition

[mg/L]

[mg O2/L/h]

[%]

blank (mean)

24

---

4

28

15

40

10

-60

400

1

-96

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
With activated sludge, a 50% decrease of the microbial respiration rate was seen with n-undecanal (EC50 = 195 mg/L, based on pure substance). This is a screening value that indicates potential disturbances in the biodegradation process of activated sludge.
Executive summary:

The toxicity of undecanal to bacteria was tested in a short-term respiration inhibition test according to OECD 209 (BASF AG, 1991). The test material was a technical product with ca. 65% undecanal. The other components were decane, undecanol and 2 -methyl decanal (no percentages given). The change in respiration rate was determined after 3 h exposure. Based on test material the 3 -h EC20 is ca. 85 mg/L, the 3 -h EC50 ca. 300 mg/L. The EC20 value was estimated to be ca. 55 mg/L, the EC50 ca. 195 mg/L based on active ingredient.

This result can be read across to n-/iso-undecanal. A detailed justification of read across is provided in the discussion field of the endpoint summary of this section.

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