The application of the Weight-Of-Evidence approach for an integrated ecological risk assessment of marine protected sites

The effective management of marine ecosystems in the face of growing anthropogenic pressures requires the integration of data from different ecological components. Holistic approaches to evaluate the ecological status of marine ecosystems are still scarce, likely due to the challenge of integrating the complex information from a variety of indicators. In this study, we provided an application of a quantitative Weight-Of-Evidence (WOE) model based on the Sediqualsoft (R) software, combining environmental and biological data to assess ecological risk in soft-bottom habitats within Natura sites 2000 in the Northern Adriatic Sea (Mediterranean Sea). Here, the WOE approach combined three lines of evidence (LOE): chemical characterization (LOE1), ecotoxicological properties (LOE4), and benthic community status (LOE5). A separate hazard quotient was derived for each LOE prior to a weighted integration into a synthetic WOE assessment. The chemical analysis of the sediments revealed concentrations of pollutants far lower the reference limits, except for As and Hg and for polycyclic aromatic hydrocarbons which determined a 'Slight' to 'Severe' chemical hazard in coastal sites. Ecotoxicological hazard was rated as 'Absent' at all sampling stations, and the analysis of benthic communities indicated 'undisturbed' conditions for most sites. The WOE approach classified the overall ecological risk to be 'Absent' for offshore sites and 'Slight' in nearshore sites. Although results suggested a general low ecological risk, the potential for future risks is recognized, especially in coastal areas, due to well-known sediment pollution in the region. The application of the WOE approach may represent a valuable tool for managing marine protected sites, and to characterize the overall ecological status of these areas and improve conservation strategies in highly anthropized environmental contexts.