An integrated approach to assess exposure and early health effects in human populations exposed to micro- and nanoplastics

Although cumulative evidence from in vitro and in vivo studies indicates that micro- and nanoplastics (MNPs) can induce toxic effects, and MNPs have been detected in several human fluids and tissues, the consequences of MNP exposure to human health still remain unknown. Human biomonitoring (HBM) studies allow assessing human exposure to MPs and associated adverse health effects, contributing to the risk assessment of these environmental pollutants. To date, reliable human exposure estimates are hindered by the lack of standardized processing and analytical methods to detect MNPs in human tissues, and limited evidence on the MNP-related adverse health effects exists. Occupational environments, where plastics are processed, may represent prioritized settings for such evaluations, as workers typically face higher exposure levels than the general population. Population sub-groups with potentially higher susceptibility, such as children and pregnant women, should also be considered. To develop effective preventive strategies, it is essential to identify and validate sensitive and specific biomarkers of exposure and early biological changes, which could result in adverse health effects. Standardized protocols integrating environmental exposure assessment with HBM, and sensitive methods for evaluating internal dose resulting from cumulative exposure to MNP particles and associated chemicals are needed. Based on the experience gathered by a multidisciplinary panel of experts belonging to the European Research Cluster to Understand the Health Impacts of MNPs (CUSP), this consensus paper describes the key elements that should be part of an integrated HBM approach for MNP exposure, emphasizing existing challenges and proposing solutions for future studies.