People Who Drink Bottled Water on a Daily Basis Ingest 90,000 More Microplastic Particles Each Year

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Sarah Sajedi was visiting Phi Phi Island, Thailand, when she was dazzled by the beautiful scenery of the Andaman Sea. However, when she looked down at her feet, she saw that the white sandy beach was covered with plastic debris, most of which was from plastic bottles.

After many years in the business world as the cofounder of an environmental software company, the experience inspired Sajedi to become a researcher. She had always had a passion for waste reduction, but she realized that the problem was consumption itself.

Thus, as a doctoral student at Concordia University in Canada, Sajedi reviewed over 140 scientific papers to determine the effects of plastic bottles on the human body. She found that people ingest an average of 39,000 to 52,000 microplastic particles per year from food and drinking water, and those who use bottled water on a daily basis ingest nearly 90,000 more microplastic particles into their bodies.

“Drinking water from plastic bottles is fine in an emergency, but it is not something that should be used in daily life,” Sajedi explains. “Even if there are no immediate effects on the human body, we need to understand the potential for chronic harm.”

Long-Term Effects Remain a Mystery

Microplastics are plastic particles ranging in size from 1 micrometer (1/1,000 of a millimeter) to 5 mm. Nanoplastics are even smaller, less than one micrometer. These particles are invisible to the naked eye, but are constantly being generated during the manufacturing, storage, transportation, and decomposition of bottles.

Low-quality plastics, in particular, are prone to release microscopic debris due to sunlight, temperature changes, and physical manipulation. Unlike other plastic particles that enter the body through the food chain, those derived from plastic bottles are of concern because they are ingested directly with drinking water.

Once in the body, microscopic plastics can enter the bloodstream and reach vital organs. This triggers a chronic inflammatory response and exposes cells to oxidative stress, which can lead to hormone system disturbances, impaired reproductive function, and damage to the nervous system. It has also been linked to various types of cancer. On the other hand, the long-term effects on health remain unclear, due to the lack of extensive testing and standardized measurement methods.

Several analytical methods exist for detecting micro- and nanoplastics, but each has its own advantages and weaknesses. Some methods can detect extremely small particles but cannot determine their chemical composition, while others can analyze composition but miss the smallest particles.

Moreover, the most accurate and reliable instruments are extremely expensive and not available to all institutions. Sajedi and his team point out that this technical limitation is a hindrance to uniform research on a global scale.

Plastic Bottles Are Not Regulated

Governments around the world are working on legislation to limit plastic waste. However, regulations are currently limited mainly to items such as plastic bags, straws, and packaging materials.

In contrast, there is little regulation of plastic bottles, which are feared to have a direct impact on health. While some regions in the US and Canada have begun to take positive steps, a global regulatory framework is still in its infancy.

Plastic pollution is not only an environmental issue, but also a public health challenge. Access to safe drinking water for everyone is one of the basic human rights, but in the long run, a sustainable water supply that does not depend on plastic bottles is needed.

Sajedi's research, which began with a scene she saw on the sandy beaches of Phi Phi Island, may be a step toward visualizing the reality of pollution that is invisible—and at the same time, a step toward changing the consciousness of society as a whole.

This story originally appeared in WIRED Japan and has been translated from Japanese.