Phenol, dodecyl-, branched

Short-term toxicity to fish

Description of key information

The acute toxicity of the water accommodated fraction (WAF) of 6.3, 13, 25, 50, and 100 mg/L mixtures of the test material to the fathead minnow, Pimephale promelas, was investigated during a study conducted at T.R. wilbury Laboratories, Inc. The test, which was designed to determine the toxicity of the WAFS of the test substance, was performed from February 8 to 12, 1994. (OECD Guideline 203 (Fish, Acute Toxicity Test)).
The test was performed at 22 ± 1°C under static, renewal conditions with a control and the WAFs of five concentrations of test substance. The dilution water was carbon-filtered, dechlorinated tap water collected at Marblehead, Massachusetts and adjusted to a hardness of 160 to 180 mg/L. Juvenile fathead minnows were procured from a commercial supplier and acclimated to test conditions for at least 14 days prior to use in the test. At the conclusion of the test control fish had an average wet weight of 0.21 g and an average total length of 29 mm.
The five WAFS were prepared by formulating 5 concentrations of the test substance and dilution water (6.3, 13, 25, 50, and 100 mg/L) in glass mixing vessels equipped with a magnetic stirrer, stirring the mixtures for approximately 24 hours, settling the mixtures for approximately 1 hour, and siphoning the water phase containing the WAF. No insoluble material was noted in any test vessels during the test.
The 96 hour median lethal concentration (LC50) of the WAFs of the test material to fathead minnows was 40 mg/L (expressed as the nominal amount of test substance used to prepare the WAF) with a 95% confidence interval of 25 to 50 mg/L. The estimated no observed effect concentration (NOEC) is 25 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

40 mg/L

Additional information

In the key study, the acute toxicity of the water accommodated fraction (WAF) of 6.3, 13, 25, 50, and 100 mg/L mixtures of the test material and water to the fathead minnow, Pimephale promelas, was investigated during a study conducted at T.R. Wilbury Laboratories, Inc. The test, which was designed to determine the toxicity of the WAF of the test substance, was performed from February 8 to 12, 1994 and was conducted according to the OECD Guideline 203 (Fish, Acute Toxicity Test) and GLP.

This study is presented as the key information as the reliability rating for this study is 2, according to the criteria of Klimisch, 1997, due to the lack of analytical confirmation of exposure concentrations. This study was conducted most recently and had less deviations than the supporting studies and was therefore chosen as the most reliable study. (Effect levels in this study were reported in terms of concentration, however as WAFs (water accomodation fraction) were used, the results should be reported in terms of loading levels (e.g. NOELR and EL50).)

Supporting studies are also avaiable for this endpoint:

- The Ward, Kowalski & Boeri, 1994 study is considered to have a reliability rating of 3, according to the criteria of Klimisch, 1997 as since the test material is highly insoluble in water, it was considered that the method used to disperse the test material was considered inappropriate and therefore this study is considered unreliable and will not be used for classification puposes. Test vessels containing 10, 35, and 100 mg/L of the test material had insoluble material on the surface and were cloudy (cloudiness increased with concentration).

Exposure of fathead minnows to the test material resulted in a 96 hour median lethal concentration (LC50) of 3.2 mg/L (95% confidence interval = 1.0 to 10 mg/L). The no observed effect concentration (NOEC) was estimated to be 1.0 mg/L.

- The Griffen & Thompson, 1981 study is considered to have a reliability rating of 3, according to the criteria of Klimisch, 1997 as since the test material is highly insoluble in water, it was considered that the method used to disperse the test material was considered inappropriate and therefore this study is considered unreliable and will not be used for classification puposes. An oily film was observed on the surface of each test chamber after delivery of the test material.

The observed 96 hour LC50 values and 95% confidence limits (C.L.) were 24 mg/l (23-30 mg/l) and 0.00010 mg/l (0.000075-0.00014 mg/l) for the test material and reference material respectively.

Also, the results indicated a 96 hour, no observed effect concentration of 5.6 mg/l.

- The Scholz, 1993 study is considered to have a reliability rating of 4, according to the criteria of Klimisch, 1997 due to a lack of detail in the report on the preparation of the test solution.

The test material was not toxic to fish when prepared as a saturated solution with an analytical concentration of <0.5 mg/L.