ONE-BLUE Project: Integrated Assessment of Contaminants of Emerging Concern (CECs) and Their Impacts in Marine Ecosystems: Mediterranean Case Study

The Mediterranean Sea is home to thousands of marine species, many of which are unique to the region and found nowhere else on Earth. Despite covering less than 1 percent of the world's ocean surface, the Mediterranean harbours 10 percent of all known marine biodiversity, making it an ecosystem of exceptional ecological significance. However, it is also among the most populated, as well as polluted and threatened marine areas in Europe, facing pressures from coastal urbanization, intense maritime traffic, plastic pollution, emerging contaminants, and climate change. Together, these factors are compromising the health and resilience of this fragile and vital ecosystem. To address these concerns, the Mediterranean has been chosen as a key case study for the European ONE-BLUE project. This collaborative initiative seeks to close critical knowledge gaps on the presence, behaviour, and impacts of CECs in the marine environment through a multidisciplinary approach that integrates targeted and non-targeted chemical analyses, bioassays, and microbial assessments. The findings will contribute to a comprehensive understanding of how these contaminants move through and affect marine ecosystems. The Mediterranean case study includes various study areas across the Spanish coast, the Tyrrhenian Sea, the northern and central Adriatic Sea, the Ionian Sea, and the Aegean Sea. Sampling areas cover diverse environments such as sites near fish and shellfish farms, industrial zones, shipyards, domestic and industrial wastewater treatment facilities, and river estuaries. Water and sediment samples are collected along the coastline and at offshore stations across various depths. Chemical analyses and toxicological tests will be conducted to assess the profile and concentration of CECs in both the water column and sediments. Additionally, biota samples from different levels of the marine food web will be examined, including plankton (collected using 53, 125, and 200-micron nets), molluscs, fish, stranded sea turtles, and stranded marine mammals. Temporal trends in synthetic chemicals will also be studied in stranded cetacean samples from 2022 and stranded turtle samples from 2012, helping to assess the impact of mitigation measures and the phase-out of specific pollutants. Finally, to complete the analysis of the marine food chain, blood samples from Scopoli's shearwater nestlings will be collected just before their fledging period at six colonies across the Mediterranean Sea.