Microplastics pose bigger threat to our health than previously feared

By Mark Waghorn via SWNS

People could be inhaling the equivalent of a credit card in microplastics every week, a new study claims.

Microplastics found in the sea, air and soil could pose a bigger threat to human health than previously feared, according to the new research.

The potentially poisonous particles collect inside the nose and at the back of the throat - "hotspots" that may increase the risk of disease.

Lead author Dr. Mohammad Islam, of the University of Technology Sydney, said: "Millions of tons of these microplastic particles have been found in water, air and soil.

"Global microplastic production is surging, and the density of microplastics in the air is increasing significantly.

"For the first time, in 2022, studies found microplastics deep in human airways, which raises the concern of serious respiratory health hazards."

Microplastics include broken-down plastic waste, synthetic fibers and beads found in personal hygiene products.

They are known to harm marine life, which mistakes them for food, and can be consumed by humans too via seafood, tap water or other food.

The study in Physics of Fluids is the first to show they stick around in human airways.

Humans might inhale about 16.2 bits of microplastic every hour - equivalent to a credit card over an entire week.

The tiny environmental debris - generated from the degradation of plastic products – usually contain toxic pollutants and chemicals.

Inhaled microplastics can pose serious health risks, so understanding how they travel in the respiratory system is essential for prevention and treatment of respiratory diseases.

The international team developed a computational fluid dynamics model to analyze transport and deposition in the upper airway.

They explored movement with a variety of shapes and sizes - ranging from spherical to tetrahedral and cylindrical - and under slow and fast breathing conditions.

Dr. Islam said: "The complicated and highly asymmetric anatomical shape of the airway and complex flow behavior in the nasal cavity and oropharynx causes the microplastics to deviate from the flow pathline and deposit in those areas.

"The flow speed, particle inertia, and asymmetric anatomy influence the overall deposition and increase the deposition concentration in nasal cavities and the oropharynx area."

Breathing conditions and microplastic size influenced the overall microplastic deposition rate in airways.

An increased flow rate led to less deposition. The largest (5.56 micron) microplastics were deposited in the airways more often than their smaller counterparts.

The authors believe the study highlights the real concern of exposure to and inhalation of microplastics, particularly in areas with high levels of plastic pollution or industrial activity.

They hope the results can help inform targeted drug delivery devices and improve health risk assessment.

Co-author Professor YuanTong Gu, of Queensland University, added: "This study emphasizes the need for greater awareness of the presence and potential health impacts of microplastics in the air we breathe."

In future, the researchers plan to analyze microplastic transport in a large scale, patient-specific whole lung model that includes environmental parameters such as humidity and temperature.