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(89-05) The importance of seasonal variations of biomarker responses and chemical contaminant levels in biomonitoring programs using two common sentinel species: Mytilus galloprovincialis and Mullus barbatus. Corsi, Ilaria*,1, Mariottini, Michela1, Menchi, Valentina1, Balocchi, Cristiana1, Sensini, Cristiana1, Focardi, Silvano1, 1 Department of Environmental Sciences, Siena, Italy ABSTRACT- Biomonitoring programs based on the integrated measurement of biomarker responses and chemical contaminant levels rarely provide a reliable evaluation of biological constraints and environmental conditions capable of triggering seasonal variations so often reported. In the present study, generic stress indices (Somatic Liver Index and Gonadosomatic Index), cytochrome P450 activities as 7-ethoxyresorufin-O-deethylase (EROD) and benzo(a)pyrene monooxygenase (BaPMO), Acetylcholinesterase functionality (AChE) and chemical contaminants levels (hexachlorobenzene, DDTs and polychlorinated biphenyls, polycyclic aromatic hydrocarbons (PAHs), nonylphenols and heavy metals) were investigated in samples of two common sentinel species M. galloprovincialis and M. barbatus collected in spring and fall 2000 along the South Adriatic and Ionic coasts of Italy. Fish gonadal histology was also investigated in order to characterise fish reproductive status. Differences among sampling sites, harbours and marine protected areas, were also investigated. Significant seasonal variations were observed in most of the parameters: both indices were higher in fish samples collected in spring as well as organochlorine, PAH and nonylphenol tissue contents probably related to the influence of reproductive period; EROD and BaPMO activities were significant higher in samples of both species collected in fall when the lowest values of AChE were also recorded. Different trends with significant seasonal variations in Pb and Cd levels, higher in spring than in fall, were observed for heavy metals. The overall results thus indicate that several physico-chemical parameters as well as biological factors are capable to interfere with biomarker responses as well as with uptake and accumulation patterns of contaminants, making their interpretation rather difficult even in long-term programs. Key words: biomonitoring, biomarkers, contaminants, gonadal histology |
