By Professor Dr. Badrul Hisham Yahaya
Plastic pollution is no longer just an environmental issue. It is now a human health concern.
Recent studies have detected microscopic plastic particles in blood, lungs, the placenta, and even reproductive cells. These particles, known as microplastics and nanoplastics, are small enough to move within the body and interact with biological systems at the cellular level.
This changes the conversation. Plastic is no longer something “out there” in oceans or landfills. It is something that may be present within us.
Microplastics are fragments smaller than 5 millimetres, while nanoplastics are even smaller and invisible to the naked eye. They originate from everyday sources such as degraded packaging, synthetic clothing, tyres, and personal care products.
Because plastic is now widespread in the environment, exposure is difficult to avoid. These particles can enter the body through food, water, and air. Once inside, some are able to cross biological barriers in the gut and lungs, allowing them to circulate and reach internal tissues.
The concern is not their presence alone, but how they interact with cells.
From a biological perspective, one area of interest is their effect on stem cells. These cells are responsible for maintaining and repairing tissues. Laboratory and animal studies suggest that microplastics can induce oxidative stress, inflammation, and DNA damage in various cell types, including stem cells.
They may also interfere with signalling pathways that regulate how cells function and renew themselves.
These effects are not trivial. Cellular stress and disrupted signalling are processes already linked to major health conditions, including cancer, cardiovascular disease, and neurodegenerative disorders. The possibility that microplastics contribute to these processes is therefore taken seriously, even if direct human evidence is still developing.
Reproductive cells appear to be particularly sensitive. Studies have reported changes in sperm quality, ovarian function, and hormone regulation following exposure. There is also emerging evidence suggesting potential effects on early embryo development.
While these findings are largely based on controlled studies, they point to a consistent concern: that microplastics may influence biological systems in ways that extend beyond immediate exposure, possibly affecting future generations.
At present, most long-term human data is still limited. This is an important point. The field is evolving, and caution is necessary when interpreting early findings.
However, the consistency of observations across studies is sufficient to justify attention. Microplastics are entering the body, interacting with cells, and influencing biological responses. That alone warrants further investigation.
From a research perspective, this is where institutions play a role. At the Pusat Kanser Tun Abdullah Ahmad Badawi (PKTAAB), Universiti Sains Malaysia, ongoing work in cell biology and regenerative medicine provides a platform to study how external factors affect cellular behaviour, including stress responses, repair mechanisms, and long-term tissue function.
Understanding how cells respond to environmental exposures is essential if we are to anticipate future health risks, rather than react to them after the fact.
The response to microplastic exposure will not come from a single solution.
Reducing plastic pollution at its source remains the most direct approach. This includes limiting unnecessary plastic use and strengthening regulations on harmful additives, particularly those known to interfere with hormonal and cellular processes.
At the same time, sustained investment in human-focused research is necessary to understand the long-term effects of low-level, chronic exposure. Laboratory findings provide important signals, but translation into real-world health outcomes requires time and careful study.
Plastic pollution has entered a new phase. It is no longer only visible in the environment. It is measurable within biological systems.
The question is no longer whether microplastics are present. It is what their presence means over time.
That answer will depend on how seriously we take the science today.
The author is the Deputy Director (Research & Networks) of Pusat Kanser Tun Abdullah Ahmad Badawi, Universiti Sains Malaysia (USM)
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