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

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

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 201 (Alga, Growth 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:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.92 mg/L

Applicant's summary and conclusion

Conclusions:

Selenastrum capricornutum, Fresh Water Algal Growth Inhibition Test with BIBR 277 BIMBIM. The study procedures described in this report were based on the EEC Directive 92/69, Publication No. L383 Part C-3 adopted December, 1992; OECD guideline No. 201, Adopted June 7, 1984; and ISO Standard 8692, First edition, 15 November 1989. BIBR 2771BIMBIM is a solid and the water solubility of BIBR 277lBIMBIM was determined to be 1.7 g/L at 20.0 r l.O°C and a pH of Ca. 4.5 (NOTOX Project 199597). However, BIBR 277/BIMBIM was much less soluble in test medium at a pH of Ca. 8.A final test was performed exposing exponentially growing algal cultures to a 5 pm BIBR 277/ BIMBIM filtrate prepared at nominal 100 mgll anddilutions of this filtrate i.e. 0.1, 1 and 10%. The initial cell density was 104 cells/mL. The total test period was 72 hours. Samples for analysiswere taken at the start and the end of the 72-hour test period. The actual test concentration measured in the filtrate prepared at nominal100 mgll decreased from 3.27 mgl/L at the start to 0.56 mg/L at the end of the test period. Hence, the average measured concentration was 1.35 mg/Lbeing the geometric mean of the concentrations measured at the start and the end of the test period. BIBR 277/ BIMBIM did not inhibit cell growth or reduce growth rate of the fresh water algae species Selenastrum capricornutum significantly at nominal 100 mg/L, the highest concentration to be tested corresponding with an average measured concentration of 1.35 mg/L.