[1,1'-Biphenyl]-2-carboxylic acid, 4'-[(1,4'-dimethyl-2'-propyl[2,6'-bi-1H-benzimidazol]-1'-yl)methyl]-, hydrochloride (1:1)

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 May - 5 June 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in GLP compliance and in accordance with several internationally established guidelines (OECD, EEC, EPA guidelines, see below).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

485-140-4

EC Name:

-

Cas Number:

515815-48-2

Molecular formula:

C33 H30 N4 O2 x HCl

IUPAC Name:

4’-(2-Propyl-4-methyl-6-(1-methylbenzimidazolyl-2-yl)-benzimidazol-1-ylmethyl)biphenyl-2-carbonsäure Hydrochlorid

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): BIBR 277 CL
- Molecular formula (if other than submission substance): C33H30N4O2 * HCl
- Molecular weight (if other than submission substance): 514.6 + 36.5 g/mol
- Structural formula attached as image file (if other than submission substance): see Reference substance
- Physical state: solid, light brownish
- Analytical purity: 99.7 %
- Purity test date: 26 March 2007
- Lot/batch No.: 70
- Expiration date of the lot/batch: 8 March 2008
- Storage condition of test material: At room temperature, dark and dry

Sampling and analysis

Analytical monitoring:

not specified

Test solutions

Vehicle:

no

Details on test solutions:

Just before the start of the test defined amounts of the test item stock solution were directly filled into each test flask. The test concentrations (10, 31, 98, 313 and 1000 mg/l) were chosen to permit the determination of the EC50. Concentrations in excess of nominal 1000 mg test item /L were not tested

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

The activated sludge used for this study was washed and centrifuged and the supernatant liquid phase was decanted. The solid material was re-suspended in isotonic saline solution and again centrifuged. This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and a ratio of wet sludge to its dry weight determined. Based on this ratio, calculated amounts of wet sludge were suspended in isotonic saline solution to yield a concentration equivalent to 4 g per litre (on dry weight basis). The pH of the activated sludge inoculum was determined to be pH 7.47. The activated sludge was used directly after conditioning.

Study design

Test type:

static

Water media type:

not specified

Limit test:

yes

Total exposure duration:

3 d

Test conditions

Test temperature:

19.2 to 20.9°C during incubation and
19.1 to 20.8°C during oxygen measurement

pH:

from pH 5.83 to 7.22

Dissolved oxygen:

from 6.7 mg O2/L to 8.0 mg O2/L

Details on test conditions:

One test solution with a final volume of 330 ml was tested per treatment in a glass flask. 10.56 ml synthetic sewage and an adequate amount of the stock solution of the test item or an adequate volue of the stock solution of the reference item was filled up with deionised water to 198 ml before the start of the test. At the start of the test 132 ml activated sludge inoculum with a sludge concentration of 4 g/L (dry weight) was added, first to first control (C1), then in time intervals of 12 minutes (an optional interal) to the test solutions of the reference item and the test item and finally to a second control (C2).

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

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; the 3 hour EC50 of the reference item 3,5-dichlorophenol was determined to be 8.54 mg/L and thus in the range of 5 to 30 mg/L for the used activated sludge batch.

Any other information on results incl. tables

Influence of test item on oxygen consumption of activated sludge

Flask No.	Test group	Concentration (mg/L)	Oxygen consumption (mg/L)	Inhibition (%) -	pH values		Oxygen concentration (mg O2/ L)
					start^*	end^*	start^*	end^*
1	Control	-	0.570	-	7.22	6.95	7.0	7.2
10	Control	-	0.560	-	7.12	7.05	7.1	7.4
	Mean	-	0.565	-	-	-	-	-
	Deviation %	-	1.8	-	-	-	-	-
5	Test item	10	0.560	0.9	7.04	6.93	8.0	7.2
6	Test item	31	0.520	8.0	6.97	6.90	7.1	7.4
7	Test item	98	0.460	18.6	6.82	6.81	6.9	6.7
8	Test item	313	0.380	32.7	6.40	6.77	7.2	6.9
9	Test item	1000	0.360	36.3	5.83	6.55	7.7	7.3

*start and end of 3 hour aeration

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

A activated sludge respiration inhibition of EC50 > 1000 mg/L was determined in a reliable study conducted according to an appropriate OECD test method.