Liverworts as heavy metals and metalloids bioindicators: bioaccumulation, biological responses and future applications in environmental biomonitoring

Biomonitoring involves using biological species, processes, and communities to assess environmental quality and monitor changes over time, particularly in response to human-induced stressors like pollution and land-use changes. Among bioindicators, bryophytes, including liverworts, are particularly effective in monitoring heavy metals (HMs) and metalloids pollution due to their ability to absorb and retain pollutants. This review examines the role of liverworts as bioindicators of HMs and metalloids pollution by analyzing their biological and physiological traits, which enable them to accumulate pollutants. It also explores the methods used in environmental monitoring with liverworts and identifies the species most frequently studied in the literature. Additionally, the review delves into the mechanisms of bioaccumulation in liverworts and the biological responses they activate and that can be used as biomarkers to highlight HM pollution. Furthermore, it highlights future and potential applications of these organisms in environmental monitoring and bioremediation. The study aims to provide a comprehensive understanding of liverworts’ effectiveness as bioindicators, contributing to better environmental management and more accurate assessments of air and water quality. Ultimately, the review underscores the importance of liverworts in biomonitoring and calls for further research to maximize their potential in assessing environmental health and remediating polluted environments.