Dibenzoyl-L-tartaric acid monohydrate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13/01/2003 - 30/01/2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

Qualifier:

according to guideline

Guideline:

other: ISO 7827: 1994

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge from laboratory wastewater plants treating municipal sewage.
- Concentration of sludge: 30 mg/I dry substance.

Duration of test (contact time):

14 d

Initial conc.:

20 mg/L

Based on:

DOC

Initial conc.:

37 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Test temperature: 22ºC
- pH: 7.4
- pH adjusted: yes
- Suspended solids concentration: 30 mg/l dry matter
- Continuous darkness: yes

SAMPLING
- Sampling frequency: samples were taken at days 0, 1, 3, 5, 7, 10, 13, 14. No further details.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (BC)
- Abiotic sterile control: yes (PC)
- Toxicity control: yes (IH)
- Other: Adsorption control (AC)

Reference substance:

aniline

Preliminary study:

TOC = 562 mg/g, DOC = 546 mg/g (non-GLP).

Key result

Parameter:

% degradation (DOC removal)

Value:

> 90 - < 100

Sampling time:

14 d

Details on results:

- Duration of the adaptation phase: 1 day.
- Duration of the degradation phase: 2 days.
- Degradation at the end of the 10-day window: 90-100 (%DOC).
- Inhibition control: degradatoin was 90-100% after 14 days (%DOC).
- Abiotic control: < 10 (%DOC) at the end of the 10-day window.
- Adsorption control: < 10 (%DOC) after 5 days.

Results with reference substance:

The reference substance achieved a 80-90% degradation after 14 days (%DOC).

Table 2. Measured values, DOC (mg/L):

Date	Day	BC1		BC2		RS		IH		PC		AC		TS1		TS2
		a	b	a	b	a	b	a	b	a	b	a	b	a	b	a	b
16.01.03	0	0.5	0.7	0.4	0.3	20.8	20.6	42.8	42.8	22.1	22.0	22.1	22.4	22.3	22.5	21.8	21.9
17.01.03	1	0.7	0.5	0.5	0.6	19.4	19.9	40.6	40.4	21.5	21.7	21.9	22.0	21.9	21.0	21.3	21.4
19.01.03	3	0.5	0.9	0.4	0.4	18.8	19.4	18.1	17.9	21.4	21.9	22.3	21.8	2.2	2.1	1.6	1.6
21.01.03	5	0.7	0.6	1.2	1.0	2.6	2.2	2.3	2.4	22.2	22.6	23.4	22.8	1.8	1.7	1.3	1.6
23.01.03	7	0.9	1.1	0.8	0.9	2.5	2.5	3.1	3.0	21.2	21.5			1.0	1.0	1.2	1.5
26.01.03	10	1.0	0.9	0.9	0.6	2.8	3.1	3.1	3.4	21.5	21.6			1.1	1.1	0.9	1.1
29.01.03	13	1.0	1.1	0.6	0.8	3.3	3.3	2.7	3.0	21.6	22.1			1.0	1.0	1.0	1.0
30.01.03	14	1.2	0.7	1.0	1.1	3.2	3.0	2.4	2.6	21.6	21.4			1.1	1.0	1.3	1.3

 

Table 3. DOC-degree (%):

Date	Day	RS	IH	PC	AC	TS1	TS2	TS mv
16.01.03	0	0	0	0	0	0	0	0
17.01.03	1	5	6	2	2	5	3	4
19.01.03	3	8	59	2	2	93	95	94
21.01.03	5	93	96	-1	1	96	97	97
23.01.03	7	92	95	3	-2	100	98	99
26.01.03	10	90	94	2		99	100	100
29.01.03	13	88	95	1		100	100	100
30.01.03	14	90	96	3		100	99	100

 

Validity criteria fulfilled:

yes

Remarks:

deviation of the degradation of the test substance in the plateau phase < 20%; degradation of the reference substance > 70% after 14 days; degradation in the inhibition control > 35% after 14 days.

Interpretation of results:

readily biodegradable

Conclusions:

The degradation of the test item was 90-100% after 14 days, passing the 10-day window. Therefore, the test item is readily biodegradable.

Executive summary:

A 14-day DOC Die-Away test was performed on the test item, according to OECD 301A / EC C.4 – A, in accordance with GLP principles. 20 mg/l DOC (corresponding to about 27 mg/l of test item) were inoculated with activated sludge (30 mg/L SS) and incubated under aerobic conditions at constant temperature (22 ± 2ºC) for 14 days. An inoculum blank (BC), an abiotic sterile control (PC), a toxicity control (IH), an adsorption control (AC) and a test with reference substance (RS, aniline) were run in parallel. The degradation of the test item attained 90-100% after 14 days, passing the 10-day window (based on %DOC). The reference substance achieved 80-90% degradation after 14 days, no significant degradation was observed in the adsorption and abiotic controls, and the toxicity control achieved 90-100% degradation after 14 days (the test item is not inhibitory). All validity criteria were met. Under test conditions, the test item is readily biodegradable.

Description of key information

Key study. Method according to OECD 301A / EU C.4 -A (DOC Die Away test), GLP study. The degradation of the test item was 90-100% after 14 days, passing the 10-day window. Therefore, the test item is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater