o-cresol

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:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Principles of method if other than guideline:

static bioassay

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

stock solutions were prepared with 50:50 acetone : water solution

Test organisms (species):

other: Salmo trutta, Oncorhynchus mykiss and Salvelinus fontinalis

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

12

Details on test conditions:

Static bioassays with the Isomers of cresol were with acclimated 2-lnch fish in 5-gallon glase jars (Lennon and Walker, 1964). We exposed 10 fish to each concentration, and 20 served as controls. The statistical methods of Litchfield and Wilcoxon (1949) were used for determining LC50 values, elope functions, and 95-percent confidence intervals. Observations were made on surfacing and signs of physio logical stress.

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

7.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salmo trutta

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

7.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salmo trutta

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

6.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salmo trutta

Duration:

6 h

Dose descriptor:

LC50

Effect conc.:

11 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Oncorhynchus mykiss

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

9.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Oncorhynchus mykiss

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

8.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Oncorhynchus mykiss

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Oncorhynchus mykiss

Duration:

6 h

Dose descriptor:

LC50

Effect conc.:

14.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salvelinus fontinalis

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

7.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salvelinus fontinalis

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

7.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salvelinus fontinalis

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

7.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: ; Salvelinus fontinalis

Sublethal observations / clinical signs:

in general, no precision qualifier reported

Validity criteria fulfilled:

not specified

Conclusions:

The acute toxicity of o-cresol to fish was determined with a static bioassay on several freshwater species. The highest toxicity is a 96h LC50 value of 6.2 mg/L with Salmo trutta. This toxicity study is classified as acceptable for assessment.

Executive summary:

The most sensitive fish species in acute toxicity tests belong to the salmonids. Howland (1969) conducted acute static tests over a period of 96 hours on the toxicity of o-cresol to three trout species. Among the fish species tested Salmo trutta (brown trout) was the most sensitive exhibiting a LC50 of 6.2 mg/L.

Description of key information

The acute toxicity of o-cresol to fish was determined in a static bioassay on several freshwater species. The highest toxicity is a 96h LC50 value of 6.2 mg/L with Salmo trutta.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

6.2 mg/L

Additional information

For various fish species short term toxicity tests are available, with LC₅₀ (96h) values ranging from 6.2 to 41 mg/l.

The lowest acute effect concentration was determined with Leuciscus idus (48h-LC50 of 2 mg/l) in a round robin test for the elaboration of a German standard method. Due to insufficient documentation, this result could not be validated. With an improved method, the same test with the same species yielded a 48h-LC50 of 10 mg/l.

The most sensitive fish species in reliable acute toxicity tests belong to the salmonids. An acute static tests was conducted over a period of 96 hours on the toxicity of o-cresol to three trout species. Among the fish species tested Salmo trutta (brown trout) was the most sensitive exhibiting a LC50 of 6.2 mg/l.