Abstract
Nowadays many chemicals are widely used in agriculture to ensure high crop yields or in veterinary/human medicine to cure diseases. After their improper usage they may contaminate the environment, persist in it and adversely affect both the target and/or the non-target organisms. One of the ways to detect the occurrence of chemicals in the environment is to assess their impact on aquatic and farm animals; both are directly or indirectly exposed via their feed and water. The micronucleus assay is a standardly used cytogenetic test for the simultaneous detection of clastogenic and aneugenic agents. Additionally, cytotoxic effects are also assessed by analysing the proliferation changes using the cytokinesis-blocked proliferation index. The occurrence of micronuclei is analysed in many types of cells like the peripheral blood cells, bone marrow or cell lines according to standards for micronuclei detection. The analysis of published results has shown that the micronucleus assay is, together with the chromosomal aberration test, one of the most often used test in genotoxicity assessment. Its results have contributed to reassessing the use of multiple chemicals available on the market. Moreover, it is a compulsory test before approving the chemical/ pesticide for the market.