Contaminants in the ecosystem

In the legislative instruments supporting the monitoring of marine-coastal waters, the need to define methods for assessing the effects of dangerous, persistent and bioaccumulative chemical substances on the biotic ecosystem communities, in addition to the criteria for determining the chemical-physical state of surface water bodies and sediment, is stressed. A general approach to assess the toxicity of chemical compounds in aquatic systems is based on toxicity tests, conducted on marine vertebrates and invertebrates, which are widely used in studies of ecotoxicology and marine biochemistry. Fish and molluscs are used as a model to highlight the biological risks caused by various polluting compounds such as benzo(a)pyrene (BaP), polycyclic aromatic hydrocarbons (PAHs), heavy metals present in highly contaminated aquatic environments, but also detergents and products deriving from human activities. The effects of these compounds, in fish, appear to be strictly species-specific and have been almost exclusively evaluated in vivo through the expression of monooxygenase levels (cytochrome P450 family), of enzymes involved in phase II of detoxification (glutathione S-transferase [GST]), UDP-glucuronosyltransferase (UDPGTS) and sulfotransferase (ST) and through oxidative stress markers. The high species-specificity of the main chemical contaminants and the need to necessarily reduce the in vivo experiments for ethical, scientific and economic reasons, makes it necessary to study the processes triggered by exposure to contaminants, in cellular systems deriving from fish species different from those used so far, such as zebrafish, carp and rainbow trout, in order to effectively assess the risks associated with the presence of xenobiotics in endemic species. Moreover, the lack of data on the effect that many of these compounds determine on the expression of oncogenes and antioncogenes can provide the basis for further research aimed at the evaluation of the molecular mechanisms through which xenobiotics can determine mutagenesis events or eventual death for apoptosis in Mediterranean fish species.
The objective of this LT is the study of transfer processes and of the dynamics of contaminants within the ecosystem in the area of interest. Targeted ecotoxicological investigations will allow us to understand the effect of contaminants, both individually and as mixtures. Finally, the results of a molecular modeling survey will allow us to verify, on a theoretical basis, the interactions and the possible combinations in the interactions between contaminants and biological molecules.

The transfer of contaminants to the human compartment through food ingestion will be verified and clearly evaluated.

The research activities envisaged are as follows:

  • Ecotoxicology and ecotoxicodynamics
  • Food


Task 3.2 Ecotoxicological and biochemical analyses in vitro

The high species-specificity of the main chemical pollutants and the need to reduce in vivo testing for ethical, scientific and economic reasons, leads to the need to find alternative methods, such as in vitro tests, to assess effectively the risks associated with the presence of xenobiotics in the environment, even at sub-lethal concentrations. Moreover, the limited availability of data related to the sub-lethal effects of the xenobiotic compounds, in the modulation of the oncogenes expression, stimulates new research aimed at evaluating the molecular mechanisms, by means of which these compounds initiate the signal transduction leading to events of cell cycle modulation, apoptosis and mutagenesis.

The main objective of the task is to evaluate, in marine systems both in vitro and in vivo, the combined actions of selected contaminants, on biochemical markers related to toxicity, inflammation, oxidative stress, cell cycle control, angiogenesis and apoptosis, in development and in cancer prevention, also through the analysis of transduction pathways and signal activation.

In detail, the specific objective of task 3.2 is to conduct ecotoxicological and biochemical investigations at the molecular and cellular levels, in order to identify biomolecular markers useful as sensors and early warning systems.

Set of toxicity tests on model organisms and cell lines of marine organisms will be performed, experiments of exposure to medium and long-term target substances will be conducted, both in vitro and on marine invertebrates and vertebrates, on which toxicity markers, oxidative stress, modulation of the metabolism and of the cell cycle will be evaluated, in order to identify molecular switches responsible for the effects observed on the investigated model systems.

 

Fig. 1: Schematic representation of the activities envisaged in Task 3.2

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