Diheptyl succinate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 - 13 Oct 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

GLP study similar to guideline study with acceptable restrictions: The test substance is tested using only one replicate for each test concentration. No analytics of the test substance is performed.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Amtsblatt der EG L 133, Teil C: Biologische Abbaubarkeit: Prüfung der Atmungshemmung

Deviations:

yes

Remarks:

The incubation period was 3 h instead of 30 minutes under continuous aeration (this was recommended by the German federal Environmental Agency

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl adipate

EC Number:

203-350-4

EC Name:

Dibutyl adipate

Cas Number:

105-99-7

Molecular formula:

C14H26O4

IUPAC Name:

1,6-dibutyl hexanedioate

Test material form:

liquid

Details on test material:

- Name of test material (as cited in study report): Adipinsäure-di-n-butylester
- Analytical purity: 99.6%
- Lot/batch No.: 2380422B

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was directly added to the test vessel and stirred overnight.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: Activated sludge collected from water treatment plant predominantly processing municipal waste water; Wupperverband, Germany; date of collection: 12 Oct 1998
- Pretreatment: none
- Initial biomass concentration: 480 mg/L

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

20 ± 2 °C

pH:

7.4 - 8.2

Dissolved oxygen:

5.8 - 8.6 mg/L at test start
2.5 - 8.0 mg/L at test end

Nominal and measured concentrations:

Nominal: 1000, 1800, 3200, 5600 and 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Aeration: continuously
- No. of vessels per concentration: 1
- No. of vessels per control: 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water
- Intervals of water quality measurement: Oyxygen concentration was measured at the beginning and at the end of the test. Temperature and pH was measured once per test concentration after 6-8 minutes.

EFFECT PARAMETERS MEASURED: Inhibition of respiration was recorded after 3 h test duration.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorphenol

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 10 000 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? yes
- Relevant effect levels: EC50 = 12 mg/L; EC10 = 2.9 mg/L

Any other information on results incl. tables

Table 1: Test results

Nominal concentration [mg/L]	Respiration rate [mg/L*h]	Abiotic loss of oxygen [mg/L*h]	Inhibition [%]
1000	27.8	0.0*	0.0
1800	27.4	0.0*	0.0
3200	25.5	0.0*	6.3
5600	29.1	0.0*	0.0
10000	28.0	0.0	0.0
Control 1	27.0
Control 2	27.4

*: The abiotic oxygen loss was measured in the 10000 mg/L treatment. As no loss of oxygen was observed, it was assessed that also no loss occurred at the lower test concentrations.