4-(α,α-dimethylbenzyl)phenol

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples (50 mL) for chemical analyses were collected from the control and all test concentrations used in the test at the beginning and end of the 96-hour test period. If there was 100 % mortality in the test concentration before 96 hours, then a sample was collected on the day of the observed mortality. All samples were frozen on dry ice in sealed 50 mL polypropylene centrifuge tubes before shipping to Reimer Analytical Associates, Inc. (Vancouver, B.C., Canada) for analysis.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

The test organism was rainbow trout (Oncorhynchus mykiss). The test was conducted with larval fish with fork lengths of 4.0 ± 1.0 cm and wet weights ranging from 0.3 to 0.5 g (approximately 50 days post hatch). The fish were obtained from a certified, disease-free commercial supplier. They were held at 15 ± 2 °C under an 8 hour dark and 16 hour light photoperiod, with a light intensity at the water surface of 133 lux. The fish were held in dechlorinated City of Calgary tap water. Dechlorinated tap water was the dilution and control water in the test. The fish were held 20 days before the test. Mortality in the stock culture was less than 0.1 % the week prior to test initiation. The fish were fed a daily ration of trout chow equal to 5 % of their body weight. The fish were not fed for 24 hours prior to test initiation or during the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

15 ± 2 °C

Dissolved oxygen:

72 to 100 % of saturation

Nominal and measured concentrations:

- Nominal concentrations: 0.2, 0.3, 0.6, 1.3, 2.5, 5.0 and 10.0 mg/L
- Measured concentrations: < 0.2, < 0.2, 0.2, 0.5, 1.5, 2.2 and 4.2 mg/L

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

0.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

0.9 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

24 h

Dose descriptor:

LC100

Effect conc.:

>= 1.5 - <= 4.2 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

The measured initial concentrations of p-Cumylphenol were, on average, 64 % lower than nominal concentrations. Final measured concentrations of p-Cumylphenol were, on average, 44 % lower than nominal concentrations. All final measured concentrations were higher than initial measured concentrations. The coefficient of variance on duplicate analyses of p-Cumylphenol from low, medium, and high test concentrations was 10 %. Values ranged from 3 to 19 % and there was no apparent trend with the concentration of p-Cumylphenol. The variance at low concentrations was of the same relative magnitude as the higher concentrations. Although this variability may account for some of the differences, the measured concentrations were consistently lower than nominal concentrations and the differences were greater than 10 %. The toxicity values were derived with an average of the initial and final measured concentrations because the differences between the measured and nominal values were greater than 20 %.
There was 100 % mortality in the 1.5, 2.2, and 4.2 mg/L test concentrations after 24 hours of exposure. The fish exposed to 0.5 mg p-Cumylphenol per L appeared stressed (lying on side and back flushing gills). The fish exposed to lower test concentrations appeared normal. The maximum concentration of p-Cumylphenol that did not cause any mortality within the 96-h test period was 0.5 mg/L. The minimum concentration of p-Cumylphenol that caused 100 % mortality within the test period was 1.5 mg/L. An LC50 (concentration causing lethality to 50 % of the organisms) was determined to be 0.9 mg/L at 24, 48, 72 and 96 hours.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this study, the 96 hour LC50 was 0.9 mg/L.

Executive summary:

An acute fish toxicity test was conducted with Oncorhynchus mykiss according to OECD Guideline 203. O. mykiss were exposed to concentrations of p-Cumylphenol ranging from <0.2 to 9.2 mg/L for 96 hours under static conditions.

Under the conditions of this study, the LC50 for p-Cumylphenol exposure was determined to be 0.9 mg/L at 24, 48, 72 and 96 hours.

Description of key information

The 96 hour LC50 of p-cumylphenol to Rainbow Trout was 0.9 mg/L

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.9 mg/L