Salt marshes are a typical environment of the Venice Lagoon (Italy) at the interface between terrestrial, marine, and freshwater habitats. They play a fundamental role in hydrodynamics by reducing tidal currents, enhancing water quality, and supporting coastal habitats and fisheries1. However, these dynamic systems are progressively more prone to erosion due to the increased frequency of extreme weather linked to climate change, leading to their rapid deterioration2. To preserve and protect these wetlands, which guarantee essential ecological functions and biodiversity of the ecosystem, protection measures have been applied (e.g., reconstruction of degraded natural marshes and creation of artificial marshes with sediments from canal maintenance). These activities have led to the formation of transitional areas, which are artificial sites undergoing a naturalization process. However, the transfer of materials from industrialized and populated areas could lead to the dislocation of known and unknown anthropogenic-related chemicals, potentially impacting the fragile natural ecosystem of salt marshes. To prevent the spread of unwanted contaminants, sediments are routinely screened for heavy metals and common organic pollutants before reallocation3. Nonetheless, when focusing on environmental preservation, it is important to exclude unwanted negative effects caused by unknown emerging contaminants, not detected by routine chemical analysis4. The thorough identification of contaminants possibly toxic for marine organisms is challenging in sediments due to the matrix chemo-physical complexity and the presence of chemicals ranging from low to high concentrations. Furthermore, the determination of the chemical fingerprint alone excludes the possibility of evaluating synergistic interactions of chemicals, as well as the extent and the categorization (e.g., estrogenic) of the toxic effect itself. For these reasons, this work explores the possibility of monitoring the salt marshes' health by using a multi-level approach that drives the chemical analysis starting from the observed toxicity. Preliminary ecotoxicological evaluations on marine model species (the microalgae Phaeodactylum tricornutum and the microcrustacean Artemia salina) are carried out using sediment extracts collected from 6 different salt marshes of the Venice Lagoon (2 natural and 4 transitional environments of different age formation). Sediment extracts are analysed with an HPLC-HRMS non-targeted approach to identify the main chemical components characterizing different marsh types and to determine the presence of emerging contaminants. Heavy metals are also determined by ICP-MS. Multivariate data exploration will clarify the correlation between observed biological effects and identified contaminants. Merging chemical and ecotoxicological data from natural, restored, or artificial salt marshes will offer an initial characterization of these distinctive habitats, providing insights on marsh’s health status and degree of restoration, laying the foundation for developing an approach to monitor the transition state of salt marshes. This study was funded by the European Union - NextGenerationEU, in the framework of the iNEST - Interconnected Nord-Est Innovation Ecosystem (iNEST ECS00000043 - CUP C43C22000340006). The views and opinions expressed are solely those of the authors and do not necessarily reflect those of the European Union, nor can the European Union be held responsible for them. The dataset was developed as part of the activities carried out by Spoke 8, Research Topic 1 (Biology of hydrosphere ecosystems)
Pettenuzzo et al. (Fri,) studied this question.