Dibutyl adipate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1988

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Only secondary literature. Original report not available.

Principles of method if other than guideline:

Oxygen consumption test (Huels method)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Chemical name of vehicle: Nonylphenol-10EO-5PO

Test organisms (species):

Pseudomonas putida

Test type:

static

Water media type:

freshwater

Total exposure duration:

5 h

Nominal and measured concentrations:

not stated

Reference substance (positive control):

not specified

Duration:

5 h

Dose descriptor:

EC10

Effect conc.:

> 1 630 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Reference 2

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:

other: 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.

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

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

because of the high oxygen demand of the activated sludge, a inoculum concentration of only 0.48 g/L were used

GLP compliance:

yes

Analytical monitoring:

no

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 (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

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

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

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

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.

Description of key information

EC10 (3h) > 10000 mg/L (nominal) for respiration rate of activated sludge (similar to OECD 209)

Additional information

One study investigating the short-term toxicity to aquatic microorganisms of Dibutyl adipate (CAS 105-99-7) is available. The GLP study was performed similar to OECD 209 using activated sludge of a predominately domestic sewage as inoculum (Müller, 1998). The test substance was directly added to the vessels. The effect of the test substance on the respiration rate was determined under static conditions using nominal concentrations in the range of 1000 to 10,000 mg/L. No respiration inhibition was measured. Hence, the 3 h-EC10 is determined to be > 10,000 mg/L on the basis of the nominal test concentration.