Butanedioic acid, 2-hydroxy-, 1,4-bis[5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octyl] ester

Toxicity to microorganisms

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,4-bis[2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctyl] 2-hydroxybutanedioate

EC Number:

807-422-1

Cas Number:

66918-01-2

Molecular formula:

C40H78O5

IUPAC Name:

1,4-bis[2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctyl] 2-hydroxybutanedioate

Details on test material:

- Name of test material (as cited in study report): SALACOS 222
- Physical state: liquid
- Analytical purity: > 98%
- Lot/batch No.: 7-2-D
- Expiration date of the lot/batch: 04/10
- Stability under test conditions: stable under storage conditions
- Storage condition of test material: room temperature (20 +/- 0.5 °C), light protected

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- culture origin: wastewater treatment plant (ARA, Ergolz II, Füllinsdorf, Switzerland)
- Method of cultivation: duplicated washing with tap water by centrifugation and decanting of supernatant liquid phase
- Preparation of inoculum for exposure:
- Pretreatment: holding three days prior to use at room temperature and continuous aeration; daily feeding with 50 mL synth. wastewater
- Initial biomass concentration: 3 g/L (dry weight)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

20 °C

pH:

start: 7.4-8.0; end: 8.1-8.2

Dissolved oxygen:

start: 8.2-8.3 mg/L; end: 8.6-9.0 mg/L

Nominal and measured concentrations:

nominal: 1000 mg/L

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Key result

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: EC50 (3h) = 19 mg/L (guideline recommendation: 5-30 mg/L)
- Other:

Applicant's summary and conclusion

Conclusions:

Due to the low water solubility of the test item only one nominal concentration (1000 mg/L) was tested. No significant inhibitory effect on the respiration rate of activated sludge after the incubation period of 3 hours was observed. Thus, the 3-hour NOEC (EC15) of the test item to activated sludge microorganisms was at least 1000 mg/L. The low variation in the oxygen consumption rate in two controls (5 %) as well as the inhibitory effect of the positive control confirmed the suitability of the selected test design.