Validation of a sediment toxicity test with the endobenthic aquatic oligochaete Lumbriculus variegatus by an international ring test

The aim of the project was the validation of a sediment toxicity test with the benthic oligochaete Lumbriculus variegatus by an international ring test. The test method was developed taking into account existing methods. A test protocol was prepared and used to run the test. A total of 14 institutions (governmental agencies, universities, contract laboratories and industry) from 7 different countries participated in the ring test. The test compound was pentachlorophenol (PCP). The participants performed a preliminary range-finding test which was used to fix the test concentrations used for the definitive test, which was conducted once by the participating laboratories (in one laboratory three variants were tested). The definitive test was designed according to an EC_x approach. NOEC and LOEC were determined additionally. In total, 15 valid tests were performed and evaluated. Chemical analysis was performed on samples taken from 6 test runs. Several courses and workshops were organised to inform and train the participants. A key aspect of the project was the detailed statistical evaluation of the test results. In a first step following practical ring-testing, the single test runs were evaluated statistically. Additionally, comparability and variability of the results, as well as advantages and difficulties of the method were evaluated and discussed at a workshop by the ring test participants. This evaluation was used to define the most appropriate biological parameters, the prerequisites for establishing a suitable test design and the validity criteria of this test. As a major outcome of the ring test, a draft test guideline, which closely follows formal requirements of the OECD test guidelines program, was prepared for submission to OECD’s Test Guideline Program.