The Environmental Pathways and Veterinary Health Implications of Microplastics and Nanoplastics: A Comprehensive Evaluation of Emerging Contaminants from a One Health Perspective.

backgroundMicroplastics (MPs) and nanoplastics (NPs) are now common in land and water ecosystems. Their spread is an increasing issue from a One Health perspective. These particles end up in soils, water, air, and farm inputs. This poses direct risks to animal health and indirect risks to people who eat animal-derived food. There are also risks from plastic additives and pesticides migrating with these particles in animal-based food. Scope and Approach: This review summarizes how MPs and NPs move in agroecosystems and livestock production. It covers their main sources, such as agricultural plastics, sludge-amended soils, plastic-lined storage, and environmental fallout. It explains how farm animals are exposed, including through feed, water, soil contact, and inhalation. Evidence is condensed for occurrence in manure, tissues, and animal products. The review also highlights key analysis challenges, especially those limiting the assessment of nanoplastic exposure. KEY

findingsField surveys show very different contamination levels in the environment. Agricultural soils range from 0.36 to 42,960 particles/kg. Livestock indicators, like contaminated feed and manure, range from 10 CONCLUSIONS AND OUTLOOK: Animal-based foods provide a major source of human exposure. MPs and NPs have been observed in milk and poultry products, such as packaged meat and eggs (mean 11.67 ± 3.98 particles/egg). There is still a research gap on raw milk taken directly from the teat and on raw eggs that have not been handled or packaged. This gap makes it hard to identify real contamination sources and control strategies. The review stresses the need for harmonized detection methods (especially for NPs), monitoring from farm to fork, and practical ways to reduce plastic use on farms and minimize contamination during processing, feed handling, and packaging.