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

Abstract

The intensive development of industry and urban structures along the seashores of the world, as well as the immense increase in marine transportation and other activities, has resulted in the deposition of thousands of new chemicals and organic compounds, endangering the existence of organisms and ecosystems. The conventional single biomarker methods used in ecological assessment studies cannot provide an adequate base for environmental health assessment, management and sustainability planning. The present study uses a set of novel biochemical, physiological, cytogenetic and morphological methods 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 and 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; glutathione S-transferase (GST) activity as an indicator of biotransformation of xenobiotics; 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, intralysosomal accumulation of cationic amphiphilic probe and activity of non-specific esterases as indicators of cell/tissue viability. Complete histopathological examination was used for diagnostics of environmental pathology. The obtained 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. Enhanced frequency of DNA lesions (alkaline and acidic DNA unwinding) and micronucleus-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 negative 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 examination demonstrates significantly higher frequencies of pathological alterations in organs of animals from polluted sites. A strong negative correlation was found between the frequency of these alterations and MXRtr activity in the same specimens. In addition to these parameters, a decrease in the viability was noted in molluscs from the polluted sites, but ChE activities remained similar at most sites. The methods applied in our study unmasked numerous early cryptic responses and negative alterations of health in populations of marine biota sampled from the polluted sites. This demonstrates that genotoxic, clastogenic and pathogenic xenobiotics a...

Temporal dynamics of gastropod fauna on subtidal sandy sediments of the Ensenada de Baiona (NW Iberian Peninsula)

“…Molluscs are an important component of benthic faunas in sandy marine sediments in terms of abundance and biomass (Cadée 1968;Troncoso and Urgorri 1993;Lourido et al 2006;Laudien et al 2007), and its study may provide valuable information about the state of benthic assemblages and environmental conditions (Bresler et al 1999;Nehring 2005;Amin et al 2009). Gastropods inhabiting subtidal soft bottoms have a great influence on the populations of other benthic animals; for instance, naticids and retusid opistobranchs are active predators of bivalves, and turrids prey on small polychaetes (e.g.…”

Marine molluscs in environmental monitoring

“…1). This list is similar, but not identical, to that used by Bresler et al (1999). Changes in the list of species were in part due to drastic changes in population size.…”

“…The analytical procedures associated with some of the examined health parameters were previously detailed (Bresler et al 1999(Bresler et al , 2001, and are thus only briefly described here. The hydrophilic fluorescent dye fluorescein was used to examine PP of external epithelia.…”

“…As described previously, the collected live molluscs were transported to the Institute for Nature Conservation Research (Tel Aviv University) and kept in aerated aquaria with artificial seawater for further experiments (Bresler et al 1999). Molluscs were thus acclimatized for 24-48 h, following which the analytical procedures were done within 2 days (i.e.…”

“…During 1996-1998, within the framework of the MARS 1 project, we used fluorescent microscopy to examine cellular-and molecular-level health parameters and antixenobiotic defence mechanisms of mollusc populations along the Red Sea, Mediterranean Sea and North Sea (Bresler et al 1999). The results obtained in that study demonstrated significant differences, at two levels, between organisms sampled in polluted and reference sites.…”