Samenvatting

In light of recent developments of the onboard ballast water treatment, WMR has developed a new protocol for the assessment of ecotoxicological effects and aims to use it as a standardised test. This study looks into the validation of this short-chronic ELS fish toxicity test, by use of the embryonic zebrafish (Danio rerio).

The compounds potassium dichromate, sodium dodecyl sulphate and copper(II)sulphate were used as reference substances for the validation process. During the tests the toxicity of these compounds were evaluated at lethal and sub-lethal levels applying the combination of two OECD guidelines, which stretches the 4 day acute embryo fish test into a short-chronic 7 days test.
During experiments, the embryos were emerged in either one of the reference toxicants over a varied concentrations range, actualising the identification of the dose-dependent relationship followed by the determination of LC-/EC50 values. In this context, adverse effects were defined experimentally while compared through a review of literature from similarly executed studies. For PDC the LC50 was determined to be 154.08 mg/L which is similar to literature values.
Sub-lethal effect showed to be minimal and alternative methods for assessing chronic toxicity may be required. SDS toxicity revealed to be instantly toxic, LC50 = 7.1 mg/L, affecting only the chorion while larvae remain unharmed.
Its toxicity shows to be relatively consistent with literature. Cu2+ toxicity mainly revealed itself in a decreased/delayed hatching success which is also reported in a great deal of studies. Results were lacking to successfully identify the LC50 of copper. Although many similarities are found between the experimentally obtained results and the literature review, further continuation of the investigation is certainly necessary.
This study illustrates a good foundation for the continuation of the research and demonstrates the potential of the method in identifying both short- and long-term effects, giving a good implication of the sensitivity of the zebrafish to the compounds.