Reaction mass of 2-methyldecan-1-al and undecanal

Toxicity to microorganisms

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

Test material information

Constituent 1

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 concentrations

Effect concentrations 1

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

Effect concentrations 2

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

Effect concentrations 3

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.

Effect concentrations 4

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.