Nano Plastics found in Bottled Water

The blog is excerpted from the Columbia University researchnews and the recently published article in the journal Proceedings of the National Academy of Sciences. The study was coauthored by Xin Gao and Xiaoqi Lang of the Columbia Chemistry Department; Huipeng Deng and Teodora Maria Bratu of Lamont-Doherty; Qixuan Chen of Columbia’s Mailman School of Public Health; and Phoebe Stapleton of Rutgers University.

Plastics, a creation of mankind have become ubiquitous in our lives and on our planet. Plastic is a wonder, but is also one of the most commonly littered items in the world. Scientists have found that virtually all the plastic we ever made is non-degradable and is still with us. Much of the plastic ends up in landfills, or worn into smaller particles in the soil, in the ocean, or in our rivers, streams, lakes and estuaries, even in the air we breath. The existence of microplastics (1 µm to 5 mm in length) and the smaller nano plastics (<1 μm) has in recent years has raised health concerns.

Micro and nano plastics originating from the use and improper disposal of plastics worldwide have increasingly raised concerns because they have been found to have a negative impacts on the endocrine components in mammals- hypothalamus, pituitary, thyroid, adrenal, testes, and ovaries. Micro and nano plastics absorb and act as a transport medium for harmful chemicals such as bisphenols, phthalates, polybrominated diphenyl ether, polychlorinated biphenyl ether, organotin, perfluorinated compounds, dioxins, polycyclic aromatic hydrocarbons, organic contaminants, and the heavy metals, which are commonly used as additives in plastic production.

Nano plastics are so tiny that, unlike microplastics, they can pass through the intestines and lungs directly into the bloodstream and travel from there to organs including the heart and brain. Nano plastics can invade individual cells, and cross through the placenta to the bodies of unborn babies. Medical researchers are studying the impact of nano plastics on a wide variety of biological systems- and they indeed  appear to be endocrine disrupting.

However, there has remained a fundamental knowledge gap in nano plastics because of the lack of effective analytical techniques. The Columbia University study linked above  developed a powerful optical imaging technique for rapid analysis of nano plastics with never before seen sensitivity and specificity. As a demonstration, micro-nano plastics in bottled water were analyzed with profiling of individual plastic particles.

The researchers searched for seven specific plastics in three “popular brands” of bottled water (they declined to name which ones), analyzing plastic particles down to just 100 nanometers in size. They spotted 110,000 to 370,000 particles in each liter, 90% of which were nano plastics; the rest were microplastics. They were also able to determine  which of the seven specific plastics they identified.

One common nano plastic founde was polyethylene terephthalate or PET. This is what many water bottles are made of so finding it was not suprising. (It is also used for bottled sodas, sports drinks and condiments such as ketchup and mayonnaise.) It probably gets into the water as bits slough off when the bottle is squeezed or gets exposed to heat. One recent study suggests that many particles enter the water when you repeatedly open or close the cap, and tiny bits abrade.

However, the number of particles of PET was outnumbered by polyamide, a type of nylon. Ironically, the scientists believe, that probably comes from plastic filters used to purify the water before it is bottled. Other common plastics the researchers found: polystyrene, polyvinyl chloride and polymethyl methacrylate, all used in various industrial processes.

The seven plastic types the scientists searched for accounted for only about 10% of all the nanoparticles they found in samples; they have no idea (yet) what the rest are. If they are all nano plastics, that would mean that nano plastic particles could number in the tens of millions per liter.

The scientists plan to continue their work, with plans to look at tap water, which also has been shown to contain microplastics, though far less than bottled water according to a meta study by Isabella Gambino et al cited below  The researchers are now studying micro plastics and nano plastics generated when people do laundry, which end up in wastewater—so far, by a count of millions per 10-pound load, coming off synthetic materials that comprise many items of clothing.

The team will also identify particles in snow that British collaborators trekking by foot across western Antarctica  are currently collecting. They also are collaborating with environmental health experts to measure nano plastics in various human tissues and examine their developmental and neurologic effects. What we have done to our planet.

 

Gambino I, Bagordo F, Grassi T, Panico A, De Donno A. Occurrence of Microplastics in Tap and Bottled Water: Current Knowledge. Int J Environ Res Public Health. 2022 Apr 26;19(9):5283. doi: 10.3390/ijerph19095283. PMID: 35564678; PMCID: PMC9103198.