Dibutyl adipate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1981

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Only secondary literature. Original report not available.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: secondary effluent, sewage, domestic, non-adapted

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Reference substance:

not specified

Parameter:

% degradation (DOC removal)

Value:

96

Sampling time:

28 d

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Only secondary literature. Original report not available.

Qualifier:

according to guideline

Guideline:

ISO Draft (BOD Test for Insoluble Substances)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

not specified

Parameter:

% degradation (O2 consumption)

Value:

> 95

Sampling time:

28 d

Interpretation of results:

readily biodegradable

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 Oct - 01 Nov 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study with acceptable restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

yes

Remarks:

Test duration was 14 days.

Qualifier:

according to guideline

Guideline:

other: Circular on Test Methods of New Chemical Substances (Japan), Biodegradation test

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: Mixture of activated sludge from STP with freshwater from rivers and lakes, marine water and marine sediment

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge was sampled from 4 sewage plants, freshwater (surface water) was sampled from 3 rivers and one lake and marine water and sediment was sampled from two bays in Japan.
- Laboratory culture: Thirty minutes after stopping of aeration, discard of about one third of the whole volume of supernatant and addition of an equal volume of a solution (pH adapted to 7.0 with NaOH) containing 5% each of glucose, peptone and potasium orthophosphate, to the settled material; restart with aeration. This procedure was repeated once per day.
- Temperature: 25 ± 2 °C
- Storage length: about one and a half month
- Preparation of inoculum for exposure: Activated sludge was mixed with old sludge which was used before.
- Concentration of sludge: 4200 mg/L

Duration of test (contact time):

14 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: as recommended in the guideline
- Test temperature: 25 ± 1 °C
- Suspended solids concentration: 30 mg/L
- Continuous darkness: not stated

TEST SYSTEM
- Culturing apparatus: closed oxgen consumption measuring machine with 300 mL culture bottle
- Number of culture flasks/concentration: 1 (water + test substance), 3 (sludge + test sub.), 1 (sludge + reference sub.), 1 (sludge)
- Measuring equipment: coulometer
- Details of trap for CO2 and volatile organics if used: soda lime

SAMPLING
- Sampling frequency: continuously until 14 days
- Sterility check if applicable: no
- Sample storage before analysis: not stated

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

90

Sampling time:

14 d

Details on results:

No 10-day window required. Substance was readily biodegradable.

Results with reference substance:

The oxygen consumption for aniline in the above used test system indicated 62.7% and 73.7% degradation after 7 days and 14 days, respectively.

Table 1. Result of analysis for BOD, HPLC and GC

		water + test sub.	sludge + test sub.			Theoretical amount
		sample No. 4	sample No. 1	sample No. 2	sample No. 3
BOD (*1)	mg	0.2	66.4	61.6	68.6	68.7
GC (residue of test substance)	mg	28.2	0.0	0.0	0.0	30.3
	% (*2)	93	0	0	0	-
HPLC (production of adipic acid from test water)	mg	1	0	0	0	17.1
	%	6	0	0	0	-
HPLC (production of adipic acid from soda lime)	mg	0	0	0	0	17.1
	%	0	0	0	0	-
GC (production of 1-butanol)	mg	1.2	0.0	0.0	0.0	17.4
	%	7	0	0	0	-

(*1) (sludge + test sub.) was calculated by substracting blank values.

(*2) Residue and production percentage was calculated as followed.

Reside percentage = Residue amount (mg) / Theoretical amount (mg) x 100

Table 2. Chart of BOD

	day 7	day 14
	BOD (mg)	BOD (mg)	Deg (%)
Sludge + Test sub.	55.8	65.6	89
Sludge + Test sub.	58.3	69.3	95
Sludge + Test sub.	54.8	63.5	86
Water + Test sub.	0.0	0.0	-
Control blank	1.0	3.7	-
Sludge + Aniline	62.7	73.7	-

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

other information

Study period:

18 Feb - 18 Mar 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restriction: Several basic information about the study design were not stated, but it was referred to the conformity with internal SOPs.

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge was collected from a waste water treatment plant which predominately treats municipal waste water; Wupperverband, Germany; date of collection: 12 Feb 1999
- Preparation of inoculum for exposure: Inoculum was aerated for 6 days.
- Pretreatment: none
- Water filtered: yes
- Type and size of filter used, if any: coarse folded filter

Duration of test (contact time):

28 d

Initial conc.:

2.62 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium
- Test temperature: 20 ± 1 °C
- pH: 7.4
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Inoculum was aerated for 6 days.
- Measuring equipment: O2 measuring advice with electrode

SAMPLING
- Sampling frequency: Samples were taken after 0, 7, 14, 21 and 28 days test duration.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Toxicity control: 2

Reference substance:

aniline

Remarks:

2 mg/L

Parameter:

% degradation (O2 consumption)

Value:

60

St. dev.:

1.4

Sampling time:

28 d

Details on results:

The test substance was degraded to 60% within 28 days test duration. However, the 10 d-window was not passed. Hence, the test substance is considered to be biodegradable but not readily biodegradable according to OECD criteria.

Parameter:

COD

Value:

2 291 mg O2/g test mat.

Results with reference substance:

The reference substance was degraded to 88% in 14 days and 98% in 28 days test duration.

Table 1: Test results

Treatment	O2 consumption after n days [mg/L]
	7 d	14 d	21 d	28 d
Test item T1	1.77	2.89	3.72	3.68
Test item T2	1.68	2.28	3.38	3.53
Degradation [%] T1	29	48	62	61
Degradation [%] T2	28	38	56	59
Mean [%]	29	43	59	60
Reference R1	2.76	4.36	4.70	4.71
Reference R2	2.71	4.15	4.62	4.67
Degradation [%] R1	57	90	98	98
Degradation [%] R2	56	86	96	97
Mean [%]	57	88	97	98
Toxicity control 1	5.93	6.97	8.85	8.77
Toxicity control 2	5.20	4.75	8.85	8.77
Degradation [%] R1	55	64	82	81
Degradation [%] R2	48	44	82	81
Mean [%]	52	54	82	81

Validity criteria fulfilled:

yes

Interpretation of results:

other: biodegradable

Description of key information

Readily biodegradable: 90% (O2 consumption) in 14 days (OECD 301C)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A reliable study investigating the ready biodegradability of Dibutyl adipate (CAS 105-99-7) is available. The study was conducted by Japanese authorities according to OECD 301C under aerobic conditions using mixtures of activated sludge from STP with freshwater from rivers and lakes, marine water and marine sediments (METI, 1995). Based on oxygen consumption a mean degradation of 90% was observed already after 14 days. Hence, Dibutyl adipate (CAS 105-99-7) is determined to be readily biodegradable according to OECD criteria.