Beyond the Label: Unveiling the Nanoplastics in Modern Society

According to a recent study, bottled water contains 100 times more tiny plastic particles than previously thought.

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By Sara Shen

Every refreshing sip from your ice-cold plastic water bottle contains thousands of microscopic menaces that enter your body: nanoplastics. 

Nanoplastics are solid particles of natural polymers with diameters that generally fall between one and 1000 nanometers. A polymer is any class of naturally or synthetically manufactured substances composed of tiny macromolecules. Nanoplastics differ from microplastics, which are larger plastic pieces with diameters less than five millimeters long. Both result from the breakdown of larger plastics during the manufacturing process of industrial products. These plastics have become increasingly relevant in modern society as their presence in our everyday lives increases through commonly sold products, including plastic water bottles.

On January 8, 2024, the Proceedings of the National Academy of Sciences of the United States of America (PNAS) released a thorough research report that revealed that a liter of bottled water could contain up to 100 times more nanoplastics than previously estimated. The usage of a hyperspectral Raman scattering imaging platform, a tool based on the Raman effect—the scattering of photons made by molecular vibrations of chemical bonds, made their research revolutionary. The tool is non-destructive, meaning it does not have to destroy the composition of the sample being tested to achieve results. The imaging platform uses the interaction between a high-intensity laser light and the chemical bonds on which the light shines to provide information on the chemical structures, identities, and contamination of the molecules present. Additionally, the machine is a label-free technique, meaning that it does not require external labels and indicators to visualize certain components, making it far more accurate than previous machines. 

Using the Raman imaging platform, PNAS researchers were able to detect nanoplastics with a diameter below 100 nanometers in plastic water bottles for the first time. Scientists found that for every liter of water, there were anywhere from 130,000 to 370,000 substance particles. Of these particles, 90 percent were nanoplastics and 10 percent were microplastics. This research was repeatedly done on three popular brands of bottled water sold in the U.S., which the researchers chose to not disclose. Researchers believe that these nanoplastics enter these plastic bottles when they are either mismanaged during production or when the plastic wears down with time. 

These nanoplastics are dangerous to humans and the environment. They are considered more harmful than microplastics because they can more easily enter the body. Microplastics can absorb dangerous heavy metals and pesticides from the environment, and when consumed, can cause poisonous effects such as inflammation, oxidative stress, or increased reactive oxygen production. Though further research may show that both micro and nanoplastics leave the body after a year, researchers stress that these small plastics are absorbed into the body and never fully disappear; they just get smaller. 

Scientists have found that unlike larger microplastics, nanoplastics will often invade individual cells and cause cellular death. This is especially problematic for pregnant women as nanoplastics can cross through the placenta, the organ that provides nutrients to a developing baby in the uterus, and harm the fetus. Additionally, once nanoplastics enter the bloodstream, they can disrupt the cellular signaling pathways, which alters the homeostasis of the immune system and causes liver and/or kidney disease, among other illnesses.

To decrease exposure to micro and nanoplastics, one should drink out of a bottle made of glass or stainless steel, rather than a bottle made of plastic. The usage of reusable grocery bags, masks, cups, straws, containers, napkins, and other reusable items is a possible further  step toward reducing nanoplastics. If plastic bottles are needed, they should be kept away from sunlight and excessive heat to slow down plastic degradation. When heated or physically scratched, plastics may release chemicals such as bisphenol A, which is linked to increased blood pressure, cardiovascular disease, and type two diabetes. Additionally, the UV radiation from sunlight can break the chemical bonds in plastics, leading to decomposition which makes it easier for the smaller plastics to be consumed. 

Opting for stainless steel or glass bottles, using reusable items, and keeping plastic products away from sunlight and heat are crucial strategies to alleviate one’s exposure to nanoplastics in efforts to protect human health.