Study details and key findings

Microplastics, which are pieces of plastic between one micrometer and half a centimeter in length, are almost everywhere in the environment. In 2018, researchers found that a single bottle of water contained an average of 325 pieces of microplastic.

In the new study, researchers examined the presence of nanoplastics, or plastic particles measuring less than one micrometer, in three popular brands of bottled water. Using a laser-based technique called stimulated Raman scattering (SRS) microscopy, the researchers were able to identify the chemical composition of cells by analyzing how they vibrated in response to light.

The researchers were able to identify seven types of plastics using the technique: polyamide, polypropylene, polyethylene, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate (PET).

Overall, the researchers found that there were between 110,000 and 370,000 plastic particles per liter of bottled water. Around 90% of the particles were nanoplastics, and the remainder were microplastics.

Both PET, which is what most plastic water bottles are made of, and polyamide, a plastic used in water filters, were found in the water. According to the researchers, this suggests that plastic in the water may be coming from both the bottle and the filtration process.

Commentary

Sherri Mason, a professor and director of sustainability at Penn State Behrend, said the new study was "really groundbreaking" and offers researchers a starting point to assess the potential health effects of nanoplastics.

"Normal humans looking at a sample of water — if there's visible plastic in it, they'll be turned off," Mason said. "But they don't realize that it's actually the invisible plastics present that are the biggest concern."

Although plastic particles have been found inside the human body, including lung tissue, blood, and the placenta, it is not yet clear how they affect our health. One concern is that endocrine-disrupting chemicals used in plastic, such as bisphenols, flame retardants, and heavy metals, may enter cells and tissues in major organs.

"Whatever microplastic is doing to human health, I will say nanoplastics are going to be more dangerous," said Wei Min, a chemistry professor at Columbia University and one of the study's authors.

Currently, researchers are investigating whether nanoplastics could be found in source water, rather than just bottled water, and whether tap water would have lower levels of nanoplastics. The SRS technique could also be used to analyze human tissue samples to understand the potential effect of plastic particles.

"If you look at our raw data, it's actually a series of images," Min said. "In fact, we have plenty of data to show if a particle has entered a particular location in a certain type of cell, then we will be able to locate it precisely in space."

In response to the study, Jill Culora, a spokesperson for the International Bottled Water Association, said the "new method needs to be fully reviewed by the scientific community and more research needs to be done to develop standardized methods for measuring and quantifying nanoplastics in our environment."

"There currently is both a lack of standardized methods and no scientific consensus on the potential health impacts of nano- and microplastic particles," Culora added. "Therefore, media reports about these particles in drinking water do nothing more than unnecessarily scare consumers." (Chasan, CBS News, 1/9; LaMotte, CNN, 1/8; Osaka, Washington Post, 1/9)

As clamor around Environmental, Social, Governance (ESG) intensifies, many healthcare leaders remain skeptical to its benefits and longevity. In part two of this series, Advisory Board's Miles Cottier and Vidal Seegobin look at five of the most common reasons for not moving on ESG and what our research indicates are the answers.