Which role for genomics in environmental risk Assessment? A case study in the venice lagoon

The European Water Framework Directive (WFD; 2000/60/EC) established a legislative framework to delineate the community action in the field of Marine Environmental Policy for preserving and restoring ecological status of surface waters. The Venice Lagoon constitutes an excellent case study for the assessment of risks derived from anthropogenic activities to the ecosystem, due to the impact of its industrial area, Porto Marghera (PM). Regulatory institutions carried out a wide survey to assess the environmental status of the Venice Lagoon in compliance with the WFD requirements. The Venetian Region has also adopted specific directives to further ensure the safety of seafood from lagoon areas, leading to the classification of one third of the Venice Lagoon as not suitable for shellfish harvesting. Here is reported the analysis of Ruditapes philippinarum sampled in three differently classified areas of the Venice Lagoon, PM, within the industrial area, and Colmata (CO), where clam harvesting is strictly interdicted, and Chioggia (CH) where clams are routinely harvested. Soft tissues were subjected to mass spectroscopy analysis to reveal several chemicals classes concentrations, and total RNA from pooled digestive glands were analysed using species-specific oligo-DNA microarrays. Chemical and gene expression analysis revealed significant differences between clams collected in PM compared to those harvested in CH. Over 500 differentially expressed transcripts were identified, including several genes with a role in drug metabolism, focal adhesion, and immune response. Conversely, clams sampled in the other interdicted area (CO) showed transcriptomic profiles similar to samples from CH and comparable levels of xenobiotics. Such findings suggest that some interdicted areas in the Venice Lagoon might need to be re-classified. The present study also serves as a proof of concept for the use of genomic tools in environmental monitoring and assessment.