An Overview on Microplastics Hazards to the Marine Ecosystem and Humans’ Health

Microplastic contamination is rapidly becoming an increasingly worrying environmental problem and poses a real threat to marine ecosystems and human health. The aim of this research was to conduct a traditional review of the current state of the art regarding the sources of MPs in marine environment, including an assessment of their toxic effect on marine organisms and transfer within the food webs and up to humans. An extensive literature search (from 1 January 2024 to 15 February 2025) yielded a total of 1027 primary research articles on this topic. This overview revealed that MPs can be ingested by marine organisms, migrate through the intestinal wall, and spread to other organs. They can biomagnify along the food chain and can be carriers of toxic chemicals and pathogen agents. Exposure of marine organisms to MPs can lead to several risks, including tissue damage, oxidative stress, and changes in immune-related gene expression, neurotoxicity, growth retardation, and behavioural abnormalities. The toxicity of MPs depends mainly on the particle size distribution and composition/characteristics of the polymer. The main routes of human exposure to MPs have been identified as ingestion (mainly seafood), inhalation, and dermal exposure. There is strong evidence of contamination of seafood by MPs, which pose a potential risk to human health. This study provides the basis for assessing MPs’ risk to marine ecosystems and potential human health impacts.