2-Propyl-4-methyl-6-(1-methylbenzimidazol-2-yl)benzimidazole

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)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

440-240-7

EC Name:

-

Cas Number:

1282554-35-1

Molecular formula:

C19 H20 N4

IUPAC Name:

2-Propyl-4-methyl-6-(1-methylbenzimidazol-2-yl)benzimidazole

Results and discussion

Effect concentrations

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Applicant's summary and conclusion

Conclusions:

The influence of BIBR 277 BIMBIM on the respiration rate of activated sludge was investigated after a contact time of 30 minutes. The study procedure was based on OECD Guideline No. 209, adopted April 4, 1984 and EEC Directive 671548 amended November 18, 1987 (87/302), Part C, Publication No. L133, adopted May 30, 1988. A stock solution of 0.5 gll was prepared in Milli-Q water. Ultrasonic dispersion (20 min.) and thorough mixing was used to accelerate dissolving and to ensure homogeneity. The stock solution was a homogeneous greylbrown suspension, the pH was 6.4. Samples for the preparation of the test vessels were taken from the stirring stock solution. 100 mg/L, corresponding to 100 mL of the prepared stock solution in 500 mL final volume, was tested in duplicate. No significant inhibition in respiration rate of the sludge was recorded at 100 mg BIBR 277 BIMBIM per litre. The duplicate measurement confirmed the result of the first measurement. Hence, the EC50 for BIBR 277 BIMBIM exceeded 100 mg/L. No further testing was needed. The respiration rates of the controls were within 15% of each other. The EC50 of the reference substance, 3,5-dichlorophenol, was 8 mg/L. Therefore, the test was considered to be valid. In conclusion, under the conditions of this present test BIBR 277 BIMBIM was not toxic to waste-water bacteria at a concentration of 100 mgll.