Results
The chemical substances selected for study belong to several classes of dangerous and persistent contaminantsof the marine environment. These include chemical elements (whose isotopic ratio can provide evidence ofnatural or anthropogenic presence), perfluoroalkyl compounds (PFAS), pesticides, hydrocarbons, endocrinedisruptors, pharmaceuticals, surfactants and microplastics. They were selected based on four criteria: 1)molecules that are dangerous and persistent in water and the marine environment; 2) substances that aremassively produced and distributed, especially if no limits to discharge are set; 3) substances that have direct orindirect health effects; 4) the presence of knowledge gaps.
We also examine the large-scale distribution of bacterial and viral populations as well as the spread of antibioticresistance genes in the marine environment.
The selection of sampling areas was based on the following criteria: 1) direction of sea currents; 2) mapping of anthropogenic impact sources along the coast as a function of organic load; 3) direction and intensity of maritime traffic; 4) levels of chemical and physical parameters capable of affecting the distribution of pollutants in the marine environment (e.g. salinity, temperature, pH); 5) availability and optimal allocation of resources.
The choice of sampling sites sought to take into account the most important of these factors through the analysis of available satellite data; currents were analysed from Copernicus Marine Service and Earth nullschool; anthropogenic impacts were studied through several platforms such as EMODnet, and The Global Wastewater Model which maps nitrogen inputs from wastewater systems, Marine Traffic for the study of merchant vessel traffic; TheOceanCleanUp for mapping plastic spills from rivers. The frequency of the sampling has been set on an annual basis and it is linked to the routes of the Italian Navy vessels.
The detection of SARS-CoV-2 in water environments has predominantly focused on wastewater, neglecting its presence in oceanic waters. This study aimed to fill this knowledge gap by investigating the occurrence of SARS-CoV-2 in remote sea and oceanic waters, at large distances from the coastline. Forty-three 500-liter samples were collected between May 2022 and January 2023 from the Atlantic Ocean, the Mediterranean Sea, the Arctic region, the Persian Gulf and the Red Sea. Using molecular detection methods including real-time RT-qPCR and nested PCR followed by sequencing, we successfully detected SARS-CoV-2 RNA in 7 of the 43 marine water samples (16.3 %), and specifically in samples taken from the Atlantic Ocean and the Mediterranean Sea. The estimated concentrations of SARS-CoV-2 genome copies in the positive samples ranged from 6 to 470 per 100 l. The presence of mutations characteristic of the Omicron variant was identified in these samples by amplicon sequencing. These findings provide evidence of the unforeseen presence of SARS-CoV-2 in marine waters even at distances of miles from the coastline and in open ocean waters. It is important to consider that these findings only display the occurrence of SARS-CoV-2 RNA, and further investigations are required to assess if infectious virus can be present in the marine environment
The global spread of antibiotic resistance genes (ARGs) in the marine environment poses a significant threat to public health and natural ecosystems. This study quantified and analysed the distribution and co-occurrence patterns of ARGs in a wide range of oceans and high seas, including the Atlantic, Arctic and Indian Ocean, the Mediterranean Sea and the Persian Gulf. Focusing on beta-lactamases (blaOXA-48, blaCTX-M-1 group, and blaTEM),sulfonamides (sul1) and tetracycline (tetA), our results showed that sul1 was ubiquitous, indicating widespread dissemination. Notably, the Mediterranean Sea exhibited higher levels of multiple ARGs in single samples, suggesting significant anthropogenic impact. Interestingly, the Arctic Ocean, particularly around the Svalbard Islands, also showed the presence of multiple ARGs, highlighting the pervasive occurrence of antibiotic resistance in remote areas. We employed two clustering approaches to explore ARG patterns, primarily focusing on identifying geographic trends and differences in ARG abundance. Additionally, we investigated potential sources of contamination, including proximity to wastewater treatment plants, ports, marine traffic, and currents
101 samples collected in the first phase of the project have been already analysed. All but one (100/101) tested positive for the presence of PFAS.
30 different PFAS monitored with occurrence between LOD and 289 ng/L
PFOA (perfluorooctanoic acid) , in the past one of the most used PFAS, detected in 72% of the samples analysed up to 10.9 ng/L
