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New Research Highlights Risks of Micro and Nanoscale Plastics

Recent studies from Rutgers Health have revealed alarming findings regarding the impact of micro- and nanoscale plastic particles on food safety. These studies indicate that such plastics may enhance the absorption of toxic chemicals in both plants and human intestinal cells, raising significant concerns about the safety of our food supply in the context of plastic pollution.

The primary study, published in NanoImpact, focused on lettuce that was subjected to both nanoscale plastic particles and prevalent environmental toxins like arsenic. The results showed a marked increase in the uptake of these harmful substances, suggesting a compounded risk of polycontamination within our food systems. In a complementary investigation published in the Microplastics journal, similar findings were observed in human intestinal tissue.

These intertwined studies imply that micro- and nano-plastics—formed from the breakdown of larger plastic debris over time—may be perpetuating a hazardous cycle. This cycle not only encourages plants to absorb greater quantities of toxic chemicals that may ultimately enter our diets but also heightens the likelihood that our bodies will absorb both the toxins and the plastics, further escalating health risks, particularly for vulnerable groups.

“To date, we have released around 7 billion metric tons of plastics into the environment, and this material continues to fragment,” remarked Philip Demokritou, director of the Nanoscience and Advanced Materials Center within the Environmental Occupational Health Sciences Institute at Rutgers University and a senior author of the studies. “These plastics contaminate everything from our drinking water to the food we consume and the air we inhale.”

Employing a cellular model simulating the human small intestine alongside a lab-based gastrointestinal system designed to replicate digestive processes, the researchers observed a nearly six-fold increase in the absorption of arsenic when nano-sized plastic particles were present, compared to instances of arsenic exposure alone. This enhancement was similarly noted with boscalid, a widely used pesticide, as indicated by researchers from Rutgers and collaborating institutions, including the Connecticut Agriculture Experiment Station and the New Jersey Institute of Technology.

The interaction appeared reciprocal; the pollutants not only facilitated the absorption of toxins but also resulted in an increased uptake of plastics by the intestinal cells, with plastic absorption approximately doubling in the presence of toxins.

“Nanoscale materials are known for their ability to circumvent biological barriers,” Demokritou explained. “The smaller the particles, the more effective they are at penetrating these protective boundaries within our bodies.”

In the accompanying study, researchers analyzed the impact of two sizes of polystyrene particles—20 nanometers and 1,000 nanometers—on lettuce plants, exposing them to arsenic and boscalid. The results highlighted that the smaller particles induced a nearly threefold increase in arsenic accumulation in edible portions of the plants compared to those exposed only to arsenic.

These effects were observed in both hydroponic setups and under more representative soil conditions. Utilizing advanced imaging and analytical techniques, the researchers confirmed the accumulation of plastic particles within plant tissues, noting that smaller particles were more adept at migrating from roots to shoots, which poses additional food safety risks.

Micro- and nanoplastics are generated through the gradual degradation of larger plastic materials present in our environment.

“Even if we halt all production and usage of plastics today, our existing plastic waste remains a pressing problem,” cautioned Demokritou.

This research is part of a broader USDA-backed initiative focused on food safety challenges related to micro- and nanoplastics. The researchers emphasize the necessity for ongoing investigations to comprehend the long-term consequences and to identify possible solutions.

“Adhering to the principles of the ‘three-R’ waste hierarchy—reduce, reuse, recycle—is essential,” Demokritou advised. “In sectors like agriculture, where plastic usage is prevalent for purposes such as weed control, we need to pivot towards biodegradable alternatives.”

Efforts are underway to create new biodegradable materials as substitutes for traditional plastics, coupled with improved methods for detecting and quantifying plastic particles in food and water. Nonetheless, the urgency to curtail further contamination remains paramount.

“Technically, addressing these challenges is within reach,” stated Demokritou. “However, it is certainly a struggle to balance the benefits of this versatile material with its associated harms, especially given the social and economic hurdles tied to plastic production and utilization.”

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