Recent research suggests that microplastics, tiny plastic particles found in the air, water, and food, may pose serious health risks, including links to certain cancers, the Washington Post reports.
A systematic review conducted by the University of California at San Francisco (UCSF) and published in the journal Environmental Science and Technology highlights potential connections between microplastics and cancers of the colon and lungs.
The study assessed a large body of research on the impact of microplastics on digestive, respiratory, and reproductive health. Drawing on evidence from studies on mice and humans, the researchers identified biological mechanisms such as chronic inflammation and oxidative stress — both of which have been linked to cancer.
“This systematic review is one of the most up-to-date assessments available right now,” said Luís Fernando Amato-Lourenço, a researcher at the Free University of Berlin who studies microplastics but was not involved in the study.
Microplastics are minuscule particles of plastic that are shed from everyday activities such as driving cars (from tire wear) and washing clothes (from synthetic fibers). These particles infiltrate air, water, and food supplies, making them virtually unavoidable in daily life.
The production of plastics, which are mostly derived from fossil fuels, is on the rise. Since the early 2000s, global plastic production has doubled, and it is expected to triple by 2060. As plastic waste continues to accumulate, so do the tiny fragments that enter human and animal bodies.
The UCSF study focused on three key health systems affected by microplastics: the digestive, respiratory, and reproductive systems. The researchers paid particular attention to changes in the colon and lungs, as well as evidence of cancer-causing effects.
The team found evidence that microplastics may be linked to colon and lung cancer, although more research is needed to confirm these findings. Chronic inflammation and oxidative stress — conditions that are already known to play roles in cancer development — were identified as potential mechanisms through which microplastics might cause harm.
“These are basically biological mechanisms that have already been shown to be part of the link between chemical exposure and cancer,” explained Tracey Woodruff, a professor at UCSF and director of the university’s Center for Reproductive Health and the Environment.
The researchers acknowledged limitations in the study. Most of the data came from animal studies, which may not fully represent how human bodies react to microplastics. Additionally, the majority of studies used spherical plastic beads, which are easier to study in a lab but not as representative of the irregular plastic fragments found in the environment.
Experts outside the study had mixed reactions to its conclusions. Some praised it as a significant step forward.
“The conclusion about microplastic exposure being a ‘suspected’ hazard to human digestive, reproductive, and respiratory systems represents a stronger stance than many previous reviews, in my opinion,” said Amato-Lourenço.
However, other scientists expressed caution. Matthew Campen, a professor and toxicologist at the University of New Mexico, argued that more research is needed.
“We are still learning about the nature of the plastics in the human body, and there is a lot of published research based on shaky assumptions,” Campen said.
The American Chemistry Council, a trade group representing the plastics industry, also questioned the findings. Kimberly Wise White, the council’s vice president of regulatory and scientific affairs, criticized the study’s methods, saying:
“This rapid review does not appear to include these considerations, calling into question the validity and quality of the conclusions.”
Despite growing concern, global regulations on microplastics remain limited. There are few laws that explicitly protect consumers from exposure to microplastics in food, water, and air. Scientists have urged policymakers to act, but negotiations for a global plastics treaty recently collapsed in Busan, South Korea.
As plastic production continues to increase, so does the likelihood of human exposure to microplastics. Critics argue that governments are moving too slowly to address the issue.
“While we’re waiting, exposures are not only continuing but are projected to increase,” said Woodruff.
