2-hydroxybenzimidazole

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-05-14 to 1991-05-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed OECD and GLP study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxybenzimidazole

EC Number:

210-412-4

EC Name:

2-hydroxybenzimidazole

Cas Number:

615-16-7

Molecular formula:

C7H6N2O

IUPAC Name:

2-hydroxybenzimidazole

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Each 24hrs new testing basins were prepared
- Using 0,095mL of Tween80/L and the testing compound a paste was prepared
- To this paste dilution water was added
- Both was homogenised using ultra-turrax and ultrasonic bath
- Stirring constantly the homogenate was transferred to the testing basin
- There, the whole basin was stirred for approx. 2hrs using a KPG-stirrer and a glass stirrer
- The test solution was clear with some sedimation of substance on the ground of the basin
- Analytical determination was +/- 20% of the expected concentration

Test organisms

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Test temperature:

Test solution: 21,4 - 21,9°C
Control: 21,4 - 22,3°C

pH:

Test solution: 7,9 - 8,3
Control: 7,9 - 8,3

Dissolved oxygen:

Test solution: 6,9 - 8,9 mg/L
Control: 7,6 - 9,4 mg/L

Nominal and measured concentrations:

1) nominal: 100mg/L, measured: 105,5mg/L
2) nominal: 100mg/L, measured: 100,5mg/L
3) nominal: 220mg/L, measured: 226 mg/L

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

148.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 3

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

220 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: In all tested concentrations the swimming behavior and breathing was affected as well as modified appearance and behavior was observed.

- Dead fish showed a dark discoloration, red gills, lockjaw and the body was bend.

Any other information on results incl. tables

Sublethal observations / clinical signs:

Table 1:

Concentration (mg/l)	Mortality
	48 h		96 h
	absolute	relative (%)	absolute	relative (%)
0	0/20	0	0/20	0
0*	0/10	0	0/10	0
100	0/10	0	0/10	0
220	10/10	100	10/10	100
LC0 (mg/l) highest tested concentration without deaths	100		100
LC50 (mg/l)	148.3		148.3
LC100 (mg/l) lowest tested concentration with 100 % deaths	220		220

0* = control group with 0.095 ml/l emulsifying agent but no test substance

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

not subject of classification. LC0 = 100 mg/l