Toxicity and Accumulation of Nanoplastics Materials: A Review of Experimental Evidence Across Biological Systems

Nanoplastics, defined as plastic particles less than 1000 nm in size, are emerging environmental contaminants of global concern. Their minute size allows them to penetrate biological barriers, potentially leading to bioaccumulation and toxic effects in a wide range of organisms. This systematic review aims to synthesize current knowledge on the toxicity and bioaccumulation of nanoplastic pollutants, focusing on their interactions with biological systems and the implications for environmental and animals and human health. Following PRISMA guidelines, a comprehensive search was conducted across PubMed, Scopus, and Web of Science for studies published between January 2010 and Sept 2025. Eligible studies reported experimental data on the bioaccumulation and/or toxicological effects of nanoplastics in vivo or in vitro. Out of 3128 initially identified records, 62 studies met inclusion criteria. Evidence shows that nanoplastics are capable of crossing cellular membranes, accumulating in tissues including the gut, liver, brain, and reproductive organs. Toxicological outcomes include oxidative stress, inflammation, genotoxicity, neurotoxicity, and reproductive impairment, with effects often dose-, size-, and surface chemistry-dependent. We concluded that the bioaccumulation and toxicity of nanoplastics have been well-documented in aquatic species and mammalian models, raising significant concerns about long-term environmental and health impacts. Further studies are needed to assess chronic low-dose exposure, human relevance, and mixture effects with other contaminants.