Micro and Nanoplastics in Terrestrial Mammals: Current Knowledge and Research Gaps

Micro and nano plastics (MNPs), originating from environmental pollution, consumer products and industrial processes, are being detected increasingly across numerous ecosystems and food chains. Their pervasive nature elevates the possibility of human and animal exposure through ingestion, inhalation and dermal contact, underscoring the need for scientific investigations into their presence and effects on “One Health”. With a view to consolidating the current state of knowledge, identifying similarity between humans and animals, research gaps and paving the way for evaluating the potential toxicological and health implications of these particles, a crucial systematic literature review has been conducted to study the detection of MNPs in specific mammalian (human and animal) tissues, whilst also examining experimental models assessing their toxicological effects. By synthesizing findings across biomedical and environmental research, the review elucidates the pathways through which these particles enter and accumulate in the body. Furthermore, it highlights the potential health risks posed by chronic exposure, including inflammatory responses, oxidative stress, and tissue damage. However, the current evidence remains insufficient to establish a quantitative balance across exposure routes and body tissues due to the lack of harmonized exposure data, heterogeneity in methodologies, inconsistent reporting, and lack of biological/clearance data. Recognition of this constraint is crucial to a more accurate contextualization of current findings, which is key for the purpose of shaping public health policies and regulatory frameworks to mitigate exposure to microplastics. Given the interdisciplinary nature of the topic, the review bridges diverse fields to create a robust foundation for future research