Microplastics and nanoplastics: mechanisms of bioaccumulation and toxicity

Abstract

Introduction. Microplastic (MP) and nanoplastics (MNP) contaminations are characterized by their microscopic size have been detected in almost all ecosystems of the planet. Objective. To perform a systematic review of the current scientific evidence corresponding to the mechanisms of interaction and affectation of MP and MNP on biological systems. Materials and Methods. The PRISMA method was applied. Results. The review and analysis of the literature refers to epidemiological evidence concerning the toxicity of PM and MNP. The analyzed literature expresses comparative and complementary trends, coming from independent lines of research, which convergently offer convincing evidence in relation to four paradigmatic mechanisms of PM and NPM toxicity: bioaccumulative capacity, vectorial role in the transport of environmental pollutants, intrinsic capacity as endocrine disruptors and translocation capacity. Conclusion. Scientific evidence shows the presence of PM and NPMs in the environment and their capacity to penetrate the human being, overcoming the blood-brain barrier or the placental barrier, which raises fears about the alterations that may be caused in the fetus and, therefore, about any transgenerational impact. The vector effect can replicate the damage, since it can also transport other contaminants to the organs of biological relevance. Their capacity as endocrine disruptors should be considered as a possible contributing factor in the emergence of metabolic dysfunctions at the global level.