Micronuclei and other nuclear abnormalities in mussels (Mytilus galloprovincialis) as biomarkers of cyto‐genotoxic pollution in mediterranean waters

Abstract

Environmental genotoxicity and cytotoxicity along the Spanish Mediterranean coast was investigated through the determination of levels of micronuclei (MN) and other nuclear abnormalities (NAs) such as nuclear buds (NB) and binucleated cells (BN) in gills of wild mussels, Mytilus galloprovincialis, from 17 study sites. The results obtained were studied in relation to the exposure to main pollutants (metals, PAHs, PCBs and DDTs), gill antioxidant enzyme activities and environmental variables (temperature and salinity). The highest MN and NB levels were found in mussels from metal-polluted sites, such as Cartagena (MN: 11.6‰, NB: 4.6‰) and Portman (MN: 8.0‰, NB: 3.5‰), where genotoxicity seemed to be related to the oxidative stress generated by exposure to metals. High frequencies of MN and NB in mussels from Algeciras 1 (MN: 8.6‰, NB: 4‰) and of MN (7.2‰) in mussels from Manilva also indicated genotoxicity, though not attributable to the pollutants analysed. In contrast, MN levels at sites highly polluted by organic contaminants such as Barcelona, Vallcarca, Tarragona and Valencia, were lower than expected (ranging from 3.8 to 5.8‰). On the other hand, evidences of cytotoxicity indicated by the high frequencies of BN found in mussels from Vallcarca, Barcelona, and Cartagena (3.9, 3.4, and 2.3‰, respectively) appeared to be specifically related to the accumulation of organic pollutants. Positive correlations found between MN and NB frequencies, and also between both NAs and water temperature, suggested that they were related genotoxic events, and that this environmental factor is able to influence their levels and has to be taken into account in the application of these biomarkers in field studies.