Our environment is full of tiny particles of plastic. By 2050, it is predicted that there will be more plastic in the ocean than fish, as the volume of plastic waste in the ocean is set to double over the next 15 years.
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Scientists have discovered huge accumulations of plastic floating on the surfaces, known as plastic islands, and hoards of plastics are regularly found washed up on beaches, even in the Arctic. Plastic waste enters the oceans and degrades over many years. However, it never fully degrades, particles become smaller and smaller, until they become microparticles and even nanoparticles (nanoplastic particles measure between 1 to 1000 nm).
Unfortunately, up to 25 million metric tons of micro and nanoplastics are added to the ocean each year. This means that nanoplastics find their way into the food we eat and the water we drink. Scientists have even found evidence that nanoplastics have contaminated the soil and are being absorbed into crops via the soil and rainwater. Studies have shown the presence of nanoplastics in high levels in apples and carrots, as well as broccoli, pears, potatoes, lettuces, radishes, and turnips.
Additionally, it has been found that nanoplastics can even float in the air, and be absorbed into the body when breathing in. Animal studies have suggested that ingesting nanoplastics via food and drink sources or breathing them in via the air can have detrimental effects.
Recently, studies have found, for the first time, evidence of nano and microplastics in human organs, including the lungs, liver, kidneys, brain and spleen. In 2022, microplastic was also detected in human blood for the first time, with plastic showing up in the blood of 4 out of every 5 participants tested.
Such developments are concerning, given that exposure to micro and nanoplastics has been linked with severely negative impacts on the body. Research has shown that plastics interfere with biological interactions and can cause damage to cell membranes and even cause cell death. There is also evidence to show that exposure to micro and nanoplastics can exacerbate many of the hallmarks of cancer. There is also an emerging field of research exploring how nanoplastics affect the brain.
Plastic Waste Around the Globe Increases
Today, around 400 million tons of plastic waste is produced each year around the world, which is roughly twice the volume of plastic waste that was produced two decades ago. With plastic production and the volume of plastic waste showing no signs of slowing, it is important to understand how exposure to micro and nanoplastics impacts human and environmental health.
Therefore, it is vital that we establish accurate and reliable methods of measuring nanoplastics in the environment. While methods have been developed to measure particles of plastic in water, soil, and biological samples, there is a lack of a standardized technique for monitoring plastic particles in the air. The development of such a method would enable scientists to understand the prevalence of airborne nanoplastics and how exposure impacts health.
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Detecting Nanoplastics in Air with Sensors
Developing methods of detecting nanoplastics in the air has been challenging due to their small size, diversity in shape, and the gaseous nature of the sample. Recently, these challenges have been overcome with innovative sensor technology.
In 2022, scientists at Ben-Gurion University of the Negev, Israel, created a novel sensor capable of detecting nanoplastics in the air. The results of the research, published in the journal American Chemical Society, describe how the novel sensor detects and determines the type, volume, and size of different nanoplastics using carbon dot films.
The team, led by Raz Jelinek, Ph.D., built on its previous work that had resulted in the development of the “e-nose”, capable of monitoring the presence of bacteria with carbon-dot-based technology. This technology was leveraged to produce a sensitive nanoplastic sensor for continuous environmental monitoring.
Carbon dots were placed in thin layers onto interdigitated electrodes the size of a fingernail. Interdigitated electrodes have two sides, with an electric field that develops between these layers -the large between known as a capacitance. When the carbon dot absorbs a piece of nanoplastic, this alters the capacitance, which is fundamental to the sensor’s nanoplastic monitoring capability.
Proof-of-concept tests proved that the sensor could determine the amount of particles existent in the air from a certain type of plastic either above or below a predetermined concentration threshold.
Future Directions
To protect the future health of the environment and the Earth’s population, it is important that we understand more about the levels of nanoplastics in the environment and their impact on health. Gaining a deeper understanding will begin with intelligent methods of sensing and monitoring nanoplastics. Today, our understanding of nanoplastics in the air is particularly limited.
Novel technologies such as the carbon-dot sensor described above will be pivotal in increasing our knowledge of how nanoplastics have entered our environment. Further research is needed to fully grasp the health implications of exposure to nanoplastics. In the future, sensor technology will likely play an important role in monitoring airborne nanoplastics to keep levels beneath a safe threshold.
References and Further Reading
Allen, D., Allen, S., Abbasi, S. et al. (2022). Microplastics and nanoplastics in the marine-atmosphere environment. Nat Rev Earth Environ 3, pp. 393–405. https://doi.org/10.1038/s43017-022-00292-x
Damian Carrington. 2022. Microplastics found in human blood for first time [online]. The Guardian. Available at: https://www.theguardian.com/environment/2022/mar/24/microplastics-found-in-human-blood-for-first-time
Detecting nanoplastics in the air [online]. Science Daily. Available at : https://www.sciencedaily.com/releases/2022/08/220823095515.htm
Lai H, Liu X, Qu M (2022). Nanoplastics and Human Health: Hazard Identification and Biointerface. Nanomaterials (Basel). 11;12(8):p. 1298. doi: 10.3390%2Fnano12081298
Molina E and Benedé S (2022). Is There Evidence of Health Risks From Exposure to Micro- and Nanoplastics in Foods? Front. Nutr. 9. p. 910094. doi: 10.3389/fnut.2022.910094
Prüst M, Meijer J, Westerink RHS (2020). The plastic brain: neurotoxicity of micro- and nanoplastics. Part Fibre Toxicol. 17(1). p. 24. doi: 10.1186/s12989-020-00358-y
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