Marine molluscs and fish as biomarkers of pollution stress in littoral regions of the Red Sea, Mediterranean Sea and North Sea

The intensive development of industry and urban structures along the seasho res of the world, as well as the immense increase in marine transportation and other activities, has resulted in the deposition of thousands of new ch emicals and organic compounds, endangering the existence of organisms and e cosystems. The conventional single biomarker methods used in ecological ass essment studies cannot provide an adequate base for environmental health as sessment, management and sustainability planning. The present study uses a set of novel biochemical, physiological, cytogenetic and morphological meth ods to characterize the state of health of selected molluscs and fish along the shores of the German North Sea, as well as the Israeli Mediterranean a nd Red Sea. The methods include measurement of activity of multixenobiotic resistance-mediated transporter (MXRtr) and the system of active transport of organic anions (SATOA) as indicators of antixenobiotic defence; glutathi one S-transferase (GST) activity as an indicator of biotransformation of xe nobiotics; DNA unwinding as a marker of genotoxicity; micronucleus test for clastogenicity; levels of phagocytosis for immunotoxicity; cholinesterase (ChE) activity and level of catecholamines as indicators of neurotoxicity; permeability of external epithelia to anionic hydrophilic probe, intralysos omal accumulation of cationic amphiphilic probe and activity of non-specifi c esterases as indicators of cell/tissue viability. Complete histopathologi cal examination was used for diagnostics of environmental pathology. The ob tained data show that the activity of the defensive pumps, MXRtr and SATOA in the studied organisms was significantly higher in the surface epithelia of molluscs from a polluted site than that of the same species from control , unpolluted stations, providing clear evidence of response to stress. Enha nced frequency of DNA lesions (alkaline and acidic DNA unwinding) and micro nucleus-containing cells was significantly higher in samples from polluted sites in comparison to those from the clean sites that exhibited genotoxic and clastogenic activity of the pollutants. In all the studied molluscs a n egative correlation was found between the MXRtr levels of activity and the frequency of micronucleus-containing hemocytes. The expression of this was in accordance with the level of pollution. The complete histopathological e xamination demonstrates significantly higher frequencies of pathological al terations in organs of animals from polluted sites. A strong negative corre lation was found between the frequency of these alterations and MXRtr activ ity in the same specimens. In addition to these parameters, a decrease in t he viability was noted in molluscs from the polluted sites, but ChE activit ies remained similar at most sites. The methods applied in our study unmask ed numerous early cryptic responses and negative alterations of health in p opulations of marine biota sampled from the polluted sites. This demonstrat es that genotoxic, clastogenic and pathogenic xenobiotics are present and a ct in the studied sites and this knowledge can provide a reliable base for consideration for sustainable development.