Registration Dossier

Ecotoxicological information

Short-term toxicity to fish

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The acute toxicity of the test item to rainbow trout was assessed according to OECD guideline 203. The 96-Hour LC50 based on the geometric mean measured test concentrations was 13 mg/L. The Lowest Observed Effect Concentration was considered to be 18 mg/L. The No Observed Effect Concentration was 10 mg/L.

Key value for chemical safety assessment

LC50 for freshwater fish:
13 mg/L

Additional information

Introduction

A study was performed to assess the acute toxicity of the test item to rainbow trout (Oncorhynchus mykiss). The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C. 1 of Commission Regulation (EC) No. 440/2008.

 

Methods

Pre-study solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation e.g. ultrasonication and high shear mixing.

A pre-study media preparation trial indicated that the use of a saturated solution method of preparation was most appropriate for this test item.

Following an initial experiment and a preliminary range-finding test, fish were exposed, in groups of 7, to an aqueous solution of the test item over a range of concentrations of 10, 18, 32, 56, and 100 mg/L for a period of 96 h at a temperature of 13 °C to 14 °C under semistatic test conditions. The test item solution was prepared by stirring an excess (200 mg/L) of test item in test medium using a propeller stirrer at approximately 1500 rpm for 24 h. After the stirring period any undissolved test item was removed by filtration (0.2 µm Sartorius Sartopore filter, first approximate 1L discarded in order to pre-condition the filter) to produce a saturated solution of the test item. This saturated solution was then diluted as necessary, to provide the test concentrations.

 

Results

Analysis of the freshly prepared test media at 0 and 72 h showed measured test concentrations in the range of 96 % to 98 % of nominal were obtained. A decline in measured test concentration was observed in the old or expired test media at 24 and 96 h in the range of 48 % to 72 % of nominal. This decline in concentration is considered to be due to the unstable nature of the test item.

Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations of the filtered test media to give a "worst case" analysis of the data.

The 96-Hour LC50based on the geometric mean measured test concentrations was 13 mg/L with 95 % confidence limits of 10 - 18 mg/L. The Lowest Observed Effect Concentration was considered to be 18 mg/L. The No Observed Effect Concentration was 10 mg/L.