Benzamide, N-[[4-[(cyclopropylamino)carbonyl]phenyl]sulfonyl]-2-methoxy-

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:

27 Dec 2005 - 13 Feb 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

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: aeration tank of a waste water plant treating predominantly domestic sewage (Wupper area water authority, STP Odenthal); mixed population of aquatic microorganisms (activated sludge)
- Laboratory culture: No
- Pretreatment: none
- Concentration of sludge: 30 mg/L ss

Duration of test (contact time):

28 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: according to guideline
- Test temperature: 22 ± 2°C
- Aeration of dilution water: 1 magnetic stirrer per test vessel
- pH: 7.6 (at the end of the test)

TEST SYSTEM
- Number of culture flasks/concentration: 3
- Measuring equipment: Oxi Top System (WTW)
- test volume: 250 mL

SAMPLING
- Sampling frequency: on day 2, 6, 8, 12, 14, 16, 20, 22, 26 and 28

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

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

30

Sampling time:

28 d

Results with reference substance:

The reference compound showed 83 % degradation after 14 days.

Result for toxicity control:

Test concentration test item: 100 mg/L

Comments: The used concentrations of the test item did not show toxic effects to bacteria.

Table 1: % Biodegradation of the test item, reference compound and toxicity control.

		% Biodegradation
Time (days)		2	6	8	12	14	16	20	22	26	28
Test item	a1	0	0	0	22	24	26	29	29	32	30
	a2	0	0	2	23	26	28	28	29	32	30
	a3	0	0	0	23	24	26	28	29	30	30
Reference compound	r1	41	74	78	83	85	87	89	90	91	91
	r2	41	73	78	83	82	85	86	88	89	90
	r3	41	71	77	81	81	83	84	86	86	88
Toxicity control	t1	18	33	35	39	49	52	54	55	56	57
	t2	18	35	37	45	52	53	55	55	57	57

 

 

 

Table 2: Validity criteria for OECD 301F.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	Difference of extremes of replicate values of the removal of the test chemical were less than 20%.	yes
Percentage degradation of the reference compound reached the pass level by day 14 (≥ 60%).	The reference compound attained a mean degradation of 83% after 14 days.	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	The toxicity control attained a mean degradation of 51% after 14 days.	yes
The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.	The oxygen uptake of the inoculum blank was 22 mg O2/L after 28 days.	yes

 

Validity criteria fulfilled:

yes

Remarks:

See Table 2 in "Any other information on results incl. tables".

Interpretation of results:

not readily biodegradable

Description of key information

 The substance is not readily biodegradable according to OECD criteria. 

Additional information

A GLP guideline study was performed to assess the ready biodegradability of the test substance.The study was conducted in accordance with the Council Directive 92/69/EEC Method C.4-D "Manometric Respirometry Test". This test method is in all essential parts identical with OECD Guideline 301 F. The test substance shows a degradation of 30% after 28 days. Therefore the substance is considered to be "not readily biodegradable".