2-naphthol

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Laboratory-cultured fathead minnows 1-2 months old were used; they averaged 0.27 g and 28 mm total length. They were not fed 48 hours before the test, and during this time they were acclimated to the test temperature of 20 +-0.5°C. The test vessels were 7.6 -liter aquaria covered with aluminum foil; each aquarium contained 6 liters of test solution and five fish. Two aquaria were used for each of the three or four test concentrations. The fish were not fed and the solutions were not aerated or changed during the 96 -hour tests. The toxicant concentration, DO, and pH were measured at 0, 24, 48, 72, and 96 hours of each test. The number of surviving animals were recorded at these times, and at hours 2 and 16 of the test. The criterion of toxic effect was defined as complete immobilization, which is equated with death.

GLP compliance:

not specified

Vehicle:

yes

Remarks:

water

Test organisms (species):

Pimephales promelas

Details on test organisms:

laboratory-cultured fathead minnows 1-2 months old

Test type:

static

Water media type:

freshwater

Hardness:

140 mg/L CaCO3

Test temperature:

20°C (+- 0,5°C)

pH:

7,8

Dissolved oxygen:

8,5 mg/L (time zero) to 4,3 mg/L (48 h later)

Reference substance (positive control):

not specified

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.46 mg/L

Basis for effect:

mortality (fish)

Details on results:

95% fiducial limits: 2.43- 3.90 mg/L

Reported statistics and error estimates:

For all tests except those with algae, the data were corrected for the control response by Abbott's (1925) formula. Because the proportion of algae that responded in the test concentrations could not be determined, the responses were expressed as a percent of the control response.
All LC50s and EC50s were estimated by probit analysis (Finney 1978).

Conclusions:

In a study of comparative acute toxicity to aquatic organisms, the LC50 of 2-naphthol for fathead minnows was calculated to 3,46 mg/L.

Executive summary:

In a study of comparative acute toxicity to aquatic organisms, the LC₅₀ of 2-naphthol for fathead minnows was calculated to 3,46 mg/L.

Description of key information

A short term toxicity study of 2-naphthol to fish was determined by Millemann et al.

No test guidelines were used but the study was well documented, met the generally accepted scientific principles and was deemed acceptable for assessment.

The species was laboratory-cultured fathead minnows (Pimephales promelas) 1-2 months old.

They were not fed 48 hours before the test, and during this time they were acclimated to the test temperature of 20 plus or minus 0.5 ^oC. The test vessels were 7.6 litre aquaria covered with aluminum foil; each aquarium contained 6 liters of test solution and five fish. Two aquaria were used for each of the three or four test concentrations. The fish were not fed and the solutions were not aerated or changed during the 96 -hour tests. The toxicant concentration, DO, and pH were measured at 0, 24, 48, 72, and 96 hours of each test. The number of surviving animals were recorded at these times, and at hours 2 and 16 of the test. The criterion of toxic effect was defined as complete immobilization, which is equated with death.

For all tests except those with algae, the data were corrected for the control response by Abbott's (1925) formula. Because the proportion of algae that responded in the test concentrations could not be determined, the responses were expressed as a percent of the control response.

All LC50s and EC50s were estimated by probit analysis (Finney 1978).

 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

3.46 mg/L