By Abbas Nazil
A groundbreaking study published in ACS ES\&T Water has revealed that nanoplastics (NPs) generated from real-world plastic waste possess a remarkable ability to adsorb toxic heavy metal ions such as lead (Pb²⁺) and cadmium (Cd²⁺), potentially exacerbating their impact on environmental and human health.
The research, led by scientists at the New Jersey Institute of Technology, shows that nanoplastics created from common plastics like polyethylene terephthalate (PET), polystyrene (PS), and polypropylene (PP) can serve as carriers—or “Trojan horses”—for heavy metals, increasing their bioavailability and toxicity in organisms.
Using a novel salt milling technique, researchers successfully produced nanoplastics from post-consumer waste materials such as PET water bottles, PS candy containers, and PP take-out food packaging without any chemical additives.
The resulting nanoparticles were irregular in shape and smaller than 200 nanometers in diameter, closely resembling environmental nanoplastics.
These particles were subjected to various characterization methods, including dynamic light scattering, electron microscopy, and spectroscopy, confirming their nanoscale size and irregular morphology.
Among the tested plastic types, polypropylene nanoplastics exhibited the highest adsorption capacity, achieving over 99 percent lead ion removal within five minutes of exposure.
Other heavy metals tested included manganese, cobalt, zinc, and cadmium, all of which were significantly adsorbed onto the nanoplastic surfaces.
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The adsorption was determined to follow a chemisorption mechanism, implying a monolayer attachment of metal ions to homogenous surfaces of the nanoplastics.
This finding raises major concerns about the environmental and biological fate of nanoplastics. Due to their small size, NPs can infiltrate living organisms through various routes including ingestion, inhalation, and dermal contact.
Once inside the body, these nanoplastics—laden with heavy metals—can cross biological barriers and deposit contaminants in sensitive tissues and organs.
Their presence has already been detected in human blood, feces, autopsied lungs, semen, and placentas.
The immune response to such foreign particles often leads to inflammation and a heightened risk of neoplasia, the abnormal and uncontrolled growth of tissue.
The study emphasizes that most previous assessments of nanoplastic toxicity used commercially produced, uniform polystyrene nanoparticles, which do not accurately represent the irregular and chemically diverse NPs found in the environment.
These new findings underscore the importance of studying real-world nanoplastic samples to better understand their interactions with other pollutants and their potential to amplify health hazards.
Given the global production of 460 million metric tons of plastic annually—of which only 9 percent is recycled—this research spotlights the urgent need for strategies to mitigate nanoplastic pollution and its capacity to carry and concentrate harmful contaminants in ecosystems and the human body.
