Sodium N-(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)-3-hydroxynaphthalene-2-carboxamidate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study according to OECD Guideline 209

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium N-(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)-3-hydroxynaphthalene-2-carboxamidate

EC Number:

278-575-4

EC Name:

Sodium N-(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)-3-hydroxynaphthalene-2-carboxamidate

Cas Number:

76918-62-2

Molecular formula:

C18H13N3O3.Na

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION OF TEST SOLUTION

Preparation of the saturated solution: The test item was weighed out (500 and 1000 mg/L ) directly into the test vessels.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Origin: Municipal sewage treatment plant of Sindlingen (Frankfurt)
- non-adapted activated sludge, receives predominantly municipal sewage and hardly industrial chemical waste

Study design

Test type:

static

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

19,2 - 20,6°C

pH:

7,0 - 7,1

Nominal and measured concentrations:

Nominal concentration: 500 mg/L , 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- glass flasks, diameter 60 mm, height 170 mm
- fill volume: appr. 480 mL
- Aeration: permanent
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 3

TEST MEDIUM
- according to Directive 88/302/EEC, Part C and OECD guideline 209

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- the pH-value of the activated sludge was measured prior to testing
- the temperature in the measuring cell was determined once durcing the measurement

TEST CONCENTRATIONS
- Test concentrations: 500 mg/L, 1000 mg/L
- 3 control replicates without test item were included.

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

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 3

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Any other information on results incl. tables

Table 1: Respiration rates and inhibition of respiration of test and reference item concentrations

	Respiration Rate [mg O2/L x h]	Inhibition [%]	Mean
Control 1	52.8	-	54.4 mg O2/L x h
Control 2	55.2	-
Control 3	55.2	-
DCP* 5 mg/L	42.0	22.8	-
DCP 20 mg/L	18.0	66.9	-
DCP 30 mg/L	15.6	71.3	-
Test item 500 mg/L	50.4	7.4	6.2 %
Test item 500 mg/L	51.6	5.1
Test item 1000 mg/L	55.2	-1.5	-1.5 %
Test item 1000 mg/L	55.2	-1.5

DCP = 3,5 -dichlorophenol

Applicant's summary and conclusion

Conclusions:

The test item is not toxic at concentration