Mussels as integrative sentinels of emerging contaminants in aquatic ecosystems

Emerging pollutants (EPs), including emerging contaminants (ECs) such as pharmaceuticals and personal care products, alongside with microplastics are increasingly causing world water quality concerns. Their typically low concentrations and irregular discharge patterns complicate monitoring efforts, and traditional chemical analyses are often insufficient to fully assess their biological relevance. In this context, biomonitoring—using living organisms to detect and quantify environmental contaminants—provides an essential complementary approach. Mussels represent one of the most effective bioindicator species in aquatic environments. Their sessile lifestyle, filter-feeding activity, and widespread distribution enable them to efficiently accumulate contaminants directly from the water column, thereby providing an integrated record of pollutant exposure over time. As a result, mussel-based biomonitoring offers ecologically meaningful insights into the presence and biological effects of emerging contaminants, contributing to more sustainable water-quality management strategies. The aim of this review is to summarize recent advances and future perspectives on the use of mussels as monitors of emerging contaminants. We address the physiological foundations supporting their reliability—including filtration processes, bioaccumulation mechanisms, and their role as “sentinel species.” Furthermore, we examine the major classes of contaminants detected in mussel tissues, ranging from pharmaceuticals to plastic polymers. Finally, the review evaluates the latest findings in the field, while also critically discussing the limitations and challenges associated with mussel-based biomonitoring.