**7. Conclusion**

When evaluating the effects of MNP in humans, routes of exposure such as absorption, ingestion, and inhalation have been established; however, a few research have described the gastrointestinal and pulmonary toxicity that develops oxidative stress, inflammatory response, and metabolic disorders.

In addition, it is essential to understand whether MNP can be further degraded after ingestion under acidic conditions of the stomach or within cell lysosomes—the long-term occurrence and fate of ingested MP and NP in the human body warrant further investigation.

Given the wide variety of particle sizes, shapes, and chemical compositions of plastics, the potentially dangerous effects of different types of MNP on human health remain largely unknown. Therefore, we recommend that future research focus on understanding the potential hazards and risks of chronic exposure to various types of MNP at relevant concentrations.

Both MP and NP can significantly affect marine organisms and human health. Since MP are small and lightweight, human-consumed marine species can ingest them quickly, accumulating this debris in tissues, circulatory systems, and the brain. Research on MP bioaccumulation and biomagnification through the food web is scarce; efforts should be directed toward clarification.

Compared to MP, NPs can spread even more efficiently in animal bodies and translocate between various organs. They also offer more effective adsorbents, transport of contaminants, and proven threats to human and animal health. However, NPs have yet to be noticed in most studies due to their enigmatic existence, limits on sampling and analysis protocols, and non-standardized basic parameter units, such as particulate matter abundance.
