Underwater noise as a marine pollutant: Quantification, assessment methods, regulatory framework and potential ecotoxicological effects.

Noise pollution represents a pervasive yet frequently neglected environmental stressor, with demonstrable implications for both human health and ecological integrity. Indeed, underwater anthropogenic noise, increasingly recognized as a substantive marine pollutant, parallels the ecological threat posed by chemical contaminants and plastic debris. Herein, we position anthropogenic underwater noise within established pollutant risk frameworks, integrating recent advancements in quantification methodologies, soundscape characterization, and ecotoxicological assessment. This work further evaluates the evolving landscape of monitoring and management practices, underscoring the necessity for integrative, evidence-based approaches. We also synthesize current knowledge on measurement techniques, propagation modeling, and dose-response relationships, with a view toward informing mitigation and regulatory strategies. Despite notable progress in acoustic sensing technologies and the emergence of international policy instruments, significant methodological and conceptual challenges persist in accurately quantifying noise exposure and implementing effective mitigation protocols. Addressing these gaps is essential to ensuring the long-term resilience of marine ecosystems against this insidious form of pollution.