SOS-Zeropol2030: Deliverable D5.4 Practical Guidance towards zero pollution in our seas for different types of pollutants

Achieving the European Union's Zero Pollution ambition requires approaches that address the complexity of pollution sources, pathways and impacts across interconnected terrestrial, freshwater and marine systems. While individual pollutants differ in their characteristics, environmental behaviour and governance needs, many of the challenges associated with preventing and reducing marine pollution are shared. This deliverable (D5.4) translates the scientific, governance and stakeholder knowledge generated throughout the SOS-ZEROPOL2030 project into practical guidance that supports the implementation of effective zero pollution approaches in European seas. The guidance adopts a source-to-sea perspective, recognising that many pressures affecting marine ecosystems originate from activities occurring outside the marine environment and therefore require coordinated action across environmental compartments, sectors and governance levels. Rather than developing new scientific evidence, D5.4 synthesises the project's key findings into transferable governance guidance while identifying where pollutant-specific implementation pathways remain necessary. The analyses undertaken within SOS-ZEROPOL2030 indicate that future progress towards marine zero pollution depends less on identifying new environmental objectives than on strengthening the coordinated implementation of existing policy ambitions across the source-to-sea continuum. This guidance was developed through the integration of multiple complementary evidence streams generated within SOS-ZEROPOL2030, including the assessment of the EU Zero Pollution Ambition and governance landscape, stakeholder surveys, Regional Seas Living Labs, the Zero Pollution Parliament, pollutant-specific guidance for per- and polyfluoroalkyl substances (PFAS) and tyre wear particles (TWPs), and the SOS-ZEROPOL2030 Strategic Framework and Roadmap. Together, these activities provide a robust evidence base for identifying common governance principles, implementation needs and future pathways towards marine zero pollution. The synthesis demonstrates that, despite substantial differences between pollutant groups, effective policy implementation consistently depends on a number of common governance conditions. These include stronger cooperation across sectors and governance levels, prevention through source control and lifecycle approaches, improved monitoring and knowledge integration, effective science-policy interfaces, meaningful stakeholder engagement, adaptive governance and coherent implementation across policy frameworks. These cross-cutting principles form the basis of the transferable guidance presented in this deliverable and the practical recommendations applicable across a wide range of marine pollution challenges. At the same time, the analysis conducted in SOS-ZEROPOL2030 highlights that transferable governance principles must be complemented by pollutant-specific implementation pathways. Persistent chemical contaminants require precautionary regulation, substitution and management of legacy contamination; nutrient pollution requires integrated catchment-to-coast management and balanced nutrient cycles; microplastics require lifecycle interventions addressing diverse diffuse emission sources; and underwater noise requires spatial, operational and source-control measures supported by harmonised monitoring and maritime planning. Together, these pathways demonstrate how common governance principles can be translated into tailored actions reflecting the characteristics of different pollutant groups. Overall, D5.4 provides an integrated framework for strengthening marine zero pollution governance by linking transferable governance principles with pollutant-specific implementation requirements. The guidance supports policymakers, competent authorities, Regional Sea Conventions, industry actors, researchers, infrastructure providers and civil society organisations in designing and implementing coordinated zero pollution actions across the source-to-sea continuum. By bridging strategic ambitions with practical implementation, it contributes to the delivery of the European Green Deal, the EU Zero Pollution Action Plan and the broader objective of achieving cleaner, healthier and more resilient European seas.