The increasing awareness of the potential health risks associated with microplastics’ (MPs) and nanoplastics’ (NPs) presence in the environment has led to a significant rise in research focused on these particles over the past few years. This review focuses on the research on MPs’/NPs’ presence and spread, pathways of exposure, toxicological effects on human health and legal framework related to MP/NP challenges. Several research projects have aimed to assess their potential harm to human health, focusing on different systems and organs. After exposure (independent of the pathway), these hazards reach the blood stream and concentrate in different organs. Further, they are responsible for harmful changes, having an immediate effect (pain, inflammation, or hormone imbalance) or lead to a long-term disease (e.g., infertility, chronic obstructive pulmonary disease, or cancer). Toxicological effects have been noticed at high concentrations of MPs, specifically polystyrene, the most widespread typical MP, but only short-term effects have been mostly studied. Significant quantities of consumed MPs have been discovered to have diverse detrimental effects, posing a threat to human welfare. The exact concentrations of microplastics that are inhaled and swallowed and then build up in the human body are still not known. Further investigation is necessary to evaluate the impact of MP/NP contamination at minimal concentrations and for prolonged durations.

(1) Background: Colon cancer is one of the most common cancer types, and treatment options, unfortunately, do not continually improve the survival rate of patients. With the unprecedented development of nanotechnologies, nanomedicine has become a significant direction in cancer research. Indeed, chemotherapeutics with nanoparticles (NPs) in cancer treatment is an outstanding new treatment principle. (2) Methods: Fe₃O₄ NPs were synthesized and characterized. Caco-2 colon cancer cells were treated during two different periods (24 and 72 h) with Fe₃O₄ NPs (6 μg/mL), various concentrations of 5-FU (4–16 μg/mL), and Fe₃O₄ NPs in combination with 5-FU (4–16 μg/mL) (Fe₃O₄ NPs + 5-FU). (3) Results: The MTT assay showed that treating the cells with Fe₃O₄ NPs + 5-FU at 16 µg/mL for 24 or 72 h decreased cell viability and increased their LDH release (p < 0.05 and p < 0.01, respectively). Furthermore, at the same treatment concentrations, total antioxidant capacity (TAC) was decreased (p < 0.05 and p < 0.01, respectively), and total oxidant status (TOS) increased (p < 0.05 and p < 0.01, respectively). Moreover, after treatment with Fe₃O₄-NPs + 5-FU, the IL-10 gene was downregulated and PTEN gene expression was upregulated (p < 0.05 and p < 0.01, respectively) compared with those of the control. (4) Conclusions: Fe₃O₄ NPs exert a synergistic cytotoxic effect with 5-FU on Caco-2 cells at concentrations below the active drug threshold levels.

Increasing awareness of the potential health risks associated with microplastics (MPs) presence in the environment has led to significant rise in research focused on these particles over the past few years. This review focuses on research on MPs presence and spread, pathways of exposure and toxicological effects on human health and legal framework related to MP challenges. Several research projects have aimed to assess their potential harm to human health. Toxicological effects have been noticed at high concentrations of MPs, specifically polystyrene, the most widespread typical MP, but only short-term effects have been mostly studied. Significant quantities of consumed MP have been discovered to have diverse detrimental effects, posing a threat to human welfare. The exact concentrations of microplastics that are inhaled and swallowed and then build up in the human body are still not known. Further investigation is necessary to evaluate the impact of MP contamination at minimal concentrations and for prolonged durations.