Analysis of micronuclei in blue mussels and fish from the Baltic and North Seas.

Micronuclei (MN) were analyzed in erythrocytes of flounder (Platichthys flesus) and wrasse (Symphodus melops) and in gill cells of blue mussels (Mytilus edulis). The organisms were collected from three study stations in the Baltic Sea and from seven stations in the North Sea (Karmsund area, Norway) 4 times. The statistically significant differences obtained were related to the season, sex of the fish, and sampling locality. Higher MN frequencies were found in fish and mussels collected from the most polluted study stations in the North Sea. The same tendency could be described in the Baltic Sea; however, it was masked by the recent oil spill from the Butinge oil terminal. Our results showing higher MN frequencies in presumably what were the most polluted study locations suggest that MN tests in fish and mussels may be used for the detection of genotoxic effects in a marine environment. The endpoint is well characterized and can be easily recognized, and the technique is convenient to use in field samplings following standard procedures and protocols.