Implementering af fiskecellelinjer i de økotoksikologiske risikovurderingsmetoder i REACH

摘要

Environmental risk assessment of chemical substances produced or imported in amounts higher than 10 tons/year require a short term toxicity test on fish. This master thesis analyses whether it is possible to use in vitro data from experiments with fish cell lines as a regulatory tool in the aquatic risk assessment. The thesis thus seeks to answer the following question: How can alternative methods like in vitro experiments supplement or replace the current in vivo methods, and if so how can they be integrated in the ecotoxicological risk assessment methods in REACH?Since environmental regulation is based on natural science it is important to reach a scientific consensus regarding whether or not in vitro methods are suitable for ecotoxicological risk assessment. I have produced experimental data using in vitro methods in an ecotoxicological setting in order to discuss this issue from an empirical angle. In order to test an in vitro assay two fish cell lines from carp, namely Cyprinus carpio brain (CCB) and Epithelioma papulosum cyprini (EPC) were exposed to the inorganic compound potassium dichromate and the organic compound acrylamide. The cytotoxicity was observed with the MTT viability assay. The EC50 values obtained in the experiment were compared to LC50 values for Cyprinus carpio (C. carpio) found in the literature. The experiments were divided in a short term toxicity test (24 h) and a time-experiment (96 h) where measurements were taken every 24 hours. My results indicated no signs of correlation between in vitro data and in vivo data, which is in accordance with some other authors. Fish cell lines were more sensitive to potassium dichromate than fish, but for acrylamide the opposite was observed. Because the obtained experimental data is conflicting it is only possible to conclude that it is difficult to draw general conclusions on that issue. However there are some advantages with in vitro assays that should not be overlooked. They are cost effective, produce less waste and are able to screen a large amount of chemicals in a short time. Based on these assumptions it can be concluded that in vitro methods do have serious limitations, that need further investigation, but as a screening tool for the tonnage band 1-10 tons/year it could be useful due to its ability to handle many contaminants in a short time. Therefore in vitro methods should be supplemented by the “Threshold approach” method, which focus on test with algae and daphnia, because they are often reported to be more sensitive than fish. In addition to the scientific possibilities it is important that the legislative foundation for implementation of in vitro methods in REACH is present. The second analysis of this thesis concerns whether it is possible to implement in vitro methods in REACH. Furthermore the analysis includes a qualitative scientific interview. This aspect is important in regard to the evaluation of the usefulness of a regulatory tool. This thesis concludes that there needs to be consensus among the scientific researchers before in vitro methods can be implemented in the aquatic risk assessment. Due to in vitro methods acceptance in the human health risk assessment of chemicals, there should be no regulatory obstacles to implement in vitro methods in environmental risk assessment of chemicals.