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Bottled water contains thousands of nano plastics so small they can invade the body’s cells, study says
In a trailblazing new study, researchers have discovered bottled water sold in stores can contain 10 to 100 times more bits of plastic than previously estimated — nanoparticles so infinitesimally tiny they cannot be seen under a microscope.
At 1,000th the average width of a human hair, nano plastics are so teeny they can migrate through the tissues of the digestive tract or lungs into the bloodstream, distributing potentially harmful synthetic chemicals throughout the body and into cells, experts say.
One liter of water — the equivalent of two standard-size bottled waters — contained an average of 240,000 plastic particles from seven types of plastics, of which 90% were identified as nano plastics and the rest were microplastics, according to the new study.
Microplastics are polymer fragments that can range from less than 0.2 inch (5 millimeters) down to 1/25,000th of an inch (1 micrometer). Anything smaller is a nano plastic that must be measured in billionths of a meter.
“This study, I have to say, is exceedingly impressive. The body of work that they put into this was really quite profound … I would call it groundbreaking,” said Sherri “Sam” Mason, director of sustainability at Penn State Behrend in Erie, Pennsylvania, who was not involved in the study.
The new finding reinforces long-held expert advice to drink tap water from glass or stainless steel containers to reduce exposure, Mason said. That advice extends to other foods and drinks packaged in plastic as well, she added.
“People don’t think of plastics as shedding but they do,” she said. “In almost the same way we’re constantly shedding skin cells, plastics are constantly shedding little bits that break off, such as when you open that plastic container for your store-bought salad or a cheese that’s wrapped in plastic.”
How many nano plastics are there?
Mason was the coauthor of a 2018 study that first detected the existence of micro- and nano plastics in 93% of samples of bottled water sold by 11 different brands in nine countries.
In that past study, Mason found each tainted liter of water held an average of 10 plastic particles wider than a human hair, along with 300 smaller particles. Five years ago, however, there was no way to analyze those tiny flecks or discover if there were more.
“It’s not that we didn’t know nano plastics existed. We just couldn’t analyze them,” Mason explained.
In the new study, published Monday in the journal Proceedings of the National Academy of Sciences, researchers from Columbia University presented a new technology that can see, count and analyze the chemical structure of nanoparticles in bottled water.
Instead of 300 per liter, the team behind the latest study found the actual number of plastic bits in three popular brands of water sold in the United States to be in between 110,000 and 370,000, if not higher. (The authors declined to mention which brands of bottled water they studied.)
However, the new technology was actually able to see millions of nanoparticles in the water, which could be “inorganic nanoparticles, organic particles and some other plastic particles not among the seven major plastic types we studied,” said coauthor and environmental chemist Beizhan Yan, an associate research professor at Columbia University’s Lamont-Doherty Earth Observatory.
The innovative new techniques presented in the study open the door for further research to better understand the potential risks to human health, said Jane Houlihan, research director for Healthy Babies, Bright Futures, an alliance of nonprofits, scientists and donors committed to reducing babies’ exposures to neurotoxic chemicals, who was not involved in the study.
“They suggest widespread human exposures to minuscule plastic particles posing largely unstudied risks,” said Houlihan in an email. “Infants and young children may face the greatest risks, as their developing brains and bodies are often more vulnerable to impacts from toxic exposures.”
Dangers to human health
Nano plastics are the most worrisome type of plastic pollution for human health, experts say. That’s because the minuscule particles can invade individual cells and tissues in major organs, potentially interrupting cellular processes and depositing endocrine-disrupting chemicals such as bisphenols, phthalates, flame retardants, per- and polyfluorinated substances, or PFAS, and heavy metals.
“All of those chemicals are used in the manufacturing of plastic, so if a plastic makes its way into us, it’s carrying those chemicals with it. And because the temperature of the body is higher than the outside, those chemicals are going to migrate out of that plastic and end up in our body,” Mason explained.
“The chemicals can be carried to your liver and your kidney and your brain and even make their way across the placental boundary and end up in an unborn child,” Mason said.
In studies of pregnant mice, researchers have found plastic chemicals in the brain, heart, liver, kidney and lungs of the developing baby 24 hours after the pregnant mother ingested or breathed in plastic particles, said study coauthor Phoebe Stapleton, associate professor of pharmacology and toxicology at Rutgers University’s Ernest Mario School of Pharmacy in Piscataway, New Jersey.
“Micro and nano plastics have been found in the human placenta at this point, Stapleton said. “They’ve been found in human lung tissues. They’ve been found in human feces; they’ve been found in human blood.”
In addition to the chemicals and toxic metals plastics may carry, another relatively unstudied area is whether the plastic polymer itself is also harming the body.
“The new frontier in plastics is understanding the polymers — the plastic part of plastic,” Mason said. “We’ve been very limited in our ability to understand the potential impact of the polymers on human health because we have not been able to detect down to that level. Now, with this new approach, we will be able to start doing so.”
CNN reached out to the International Bottled Water Association, which represents the industry, for a response to the study’s findings.
“This 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 nano plastics in our environment,” a spokesperson for the association told CNN via email.
“There currently is both a lack of standardized methods and no scientific consensus on the potential health impacts of nano- and microplastic particles. Therefore, media reports about these particles in drinking water do nothing more than unnecessarily scare consumers.”
Which plastics are you swallowing?
The study’s new method of identifying nanoparticles in bottled water relies on a modified version of Raman spectroscopy, a laser-based technique that can analyze the chemical composition of cells by measuring how molecules vibrate in response to light.
The altered version, called stimulated Raman scattering microscopy, or SRS, adds a second laser to “amplify the previous signal by several orders of magnitude, allowing the previously unseen nanoparticle to be detected,” said senior author Wei Min, a professor of chemistry at Columbia University in New York City, who coinvented SRS in 2008.
“This study is the first one to apply this microscopy to the nano plastic world,” Min said.
By dramatically boosting the image, SRS can clearly identify and capture images of nanoparticles in microseconds rather than the hours needed by the older technique — and do so without harming the tissues being imaged.
“But seeing the particles is not good enough because how do you know this is plastic or not? To do that we developed a new machine-based learning technology that allows us to identify and classify which plastic it is,” Yan said.
At the time of publication, the study’s algorithm was able to identify seven types of plastics: polyamide, polypropylene, polyethylene, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate.
“Based on other studies we expected most of the microplastics in bottled water would come from leakage of the plastic bottle itself, which is typically made of PET (polyethylene terephthalate) plastic,” said lead author Naixin Qian, a doctoral student in chemistry at Columbia University.
“However, we found there’s actually many diverse types of plastics in a bottle of water, and that different plastic types have different size distributions,” she said. “The PET particles were larger, while others were down to 200 nanometers, which is much, much smaller.”
Studies have found that particles of PET plastics can be broken off by repeatedly opening and closing the cap of the bottle, crushing the bottle or subjecting it to heat, such as in a car.
Much more research to be done
Now that nano plastics can be identified and classified, it’s possible to research the answer to all sorts of questions. For example, if the nano plastics floating in the bottled water weren’t from the bottle itself, where did they come from? The Columbia team is investigating a hypothesis that the other nano plastics may come from source water, perhaps tainted by some part of the manufacturing process.
Another important question: Which has fewer nano plastics and chemical residues, bottled or tap water?
“Several studies have reported lower microplastic levels in tap water. Hence, it’s plausible to expect lower nano plastic levels in tap water as well, considering their common sources,” Yan said. “We’re conducting research on that right now.”
What happens once the plastic polymer and the endocrine-disrupting chemicals enter the body’s cells? Do the invaders remain, wreaking havoc by disrupting or damaging cellular processes, or does the body succeed in kicking them out?
“We know these microparticles are getting into the body, and we know even greater percentages of the smaller nanoparticles are getting into cells, but we don’t know exactly where they’re going in the cell or what they are doing,” Stapleton said. “And we don’t know if or how they’re getting back out again.”
However, the new technology is well-suited to analyzing human tissue samples and should soon provide some answers, Min said.
“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.”
While science explores these and other questions, there are things people can do to reduce their exposure to plastics, said Healthy Babies, Bright Futures’ Houlihan.
“We can avoid consuming foods and beverages in plastic containers. We can wear clothing made from natural fabrics and buy consumer products made from natural materials,” Houlihan said. “We can simply take stock of the plastic in our daily lives and find alternatives whenever feasible.”
注释：
trailblazing: adj
表示"领导性的, 带头的"，如：In other disciplines our “field work” techniques yield many trailblazing results. 在其它领域也取得了许多先端性，开拓性的成果。
infinitesimal : adj
表示"极小的"，means "infinitely or immeasurably small"，如：The body's annual intake of metallic iron is infinitesimal. 人体对金属铁的年摄入量是微不足道的。
teeny：adj
表示" 极小的；微小的；青少年的"，means "(used informally) very small"，如：I was just a teeny bit disappointed. 我只是有一点点失望。
groundbreaking: adj
表示" 创新的"，means "being or producing something like nothing done or experienced or created before"，如：That's not enough to define a platform that allows really smart people to come up with groundbreaking ideas. 这些并不足以定义一个平台是否能让一些聪明的使用者提出更创新的点子。
taint: v
表示" 污染；中毒"，如：Such assurances have done little to quiet fears that Connell continues to taint the air. 这样的保证丝毫没有安抚人们对康奈尔继续污染空气的担忧。
fleck：n
表示" 斑点；微粒"，means "make a spot or mark onto"，如：The garlic moss has no yellow fleck or other virus. 蒜苔没有黄斑点及其它病毒。
neurotoxic: adj
表示" 毒害神经的"，means "poisonous to nerves or nerve cells"，如：And their venom is called neurotoxic. 它们的毒液称为神经毒素。
endocrine: n
表示" 内分泌；"，如：The three endocrine axes change as male grow aged. 随着年龄的增大，男性的内分泌轴也随之发生变化。
bisphenols: n
表示" 双酚类"，如：Bisphenol A is a chemical widely used to make hard, polycarbonate plastic. 双酚A是一种广泛用于硬聚碳酸酯塑料的化学品。
phthalates
表示"邻苯二甲酸酯"，如：That's because retail products aren't required to list individual ingredients of fragrances, which are a common phthalate source. 那是因为零售商品通常不要求列出芳香剂的单独成分，那是邻苯二甲酸盐共同的源头。
retardants: n
表示"抑止剂"，means ""，如：Will Halogenated Flame Retardants Be Replaced in the Future? 卤系阻燃剂会被取代吗?
polyfluorinated: adj
表示" 多氟化的"，如：Polyfluorinated Ethylene Propylene 聚全氟乙丙烯
placental: adj
表示" 胎盘的；胎座的"，如：All mammals except monotremes and marsupials are placental mammals. 除了单孔类动物和有袋动物之外所有的哺乳动物都是有胎盘的哺乳动物。
algorithm: n
表示" 算法"，means "a precise rule (or set of rules) specifying how to solve some problem"，如：The compare algorithm is used to do the comparison. 比较算法是用来比较属性值的。
polyamide: n
表示"聚酰胺；尼龙"，如：It's a two-component epoxy polyamide cured conducting electrostatic paint. 为双组份环氧聚酰胺固化的导静电漆。
polypropylene: n
表示"聚丙烯"，如：The most important fiber is polypropylene.最重要的纤维是聚丙烯纤维。
polyethylene: n
表示" 聚乙烯"，如：Polyethylene is an excellent barrier to water vapor. 聚乙烯确保水蒸汽的性能良好。
polymethyl methacrylate: n
表示"聚甲基丙烯酸甲酯,有机玻璃"，如：Polymethyl methacrylate is the most frequently used denture base material in clinic. 聚甲基丙烯酸甲酯是临床上最常用的义齿基托材料。
polyvinyl chloride: n
表示" 聚氯乙烯"，如：PVC in the combustion will release hydrogen chloride and other toxic gases , Such as dioxin.
聚氯乙烯在燃烧时会释放出氯化氢和其它有毒气体，例如二恶英。
polystyrene: n
表示" 聚苯乙烯"，如：The computer is packed in expanded polystyrene before being shipped. 这台计算机运送前用弹性聚苯乙烯包装。
polyethylene terephthalate: n
表示"聚对苯二甲酸乙二醇酯"，如：Most commercial water is packaged in PET bottles (polyethylene terephthalate) which are inexpensive to recycle and do not release chlorine if burned. 大多数瓶装水的塑胶瓶用聚乙烯对苯二甲酸酯(PET)制造，回收再利用时消耗较少能源，且在燃烧时不会释放氯。
中文简要说明：
美国哥伦比亚大学（Columbia University）团队在三大知名瓶装水品牌中验出数十万个塑料微粒，比过去已知的数据高出10倍至百倍，专家警告，当中的纳米塑料微粒小到能进入人体细胞，建议民众以玻璃或不锈钢容器喝水。
美国有线电视新闻网（CNN）报导，哥伦比亚大学研究团队利用新技术，检测全美三大知名瓶装水品牌的塑料微粒含量，每公升竟验出11万至37万个塑料碎片，当中90％为纳米塑料微粒（nanoplastics），其余为塑料微粒（microplastics）。
研究共同作者、哥大环境化学家颜备战（Beizhan Yan）表示，这项新技术实际上能够验出数百万个纳米颗粒，这些纳米颗粒包含团队研究的7种塑料类形以外的无机纳米颗粒、有机颗粒等。
这份研究已于8日发表于美国《国家科学院学报》（Proceedings of the National Academy of Science），研究作者拒绝透露检验哪三大瓶装水品牌，因为他们认为所有瓶装水都含有纳米塑料微粒，只列出热门品牌名称可能不公平。
事实上哥大的研究成果较2018年的一份相似研究高出10倍至100倍。当年宾州州立大学伊利比伦德学院（Penn State Behrend）永续发展主任梅森（Sherri “Sam” Mason）与团队检验9国的11种瓶装水品牌，检测出93％样本中有塑料微粒，当中平均每公升样本中验出10个比头发还粗的塑料微粒、300个较小的微粒，不过当时的技术还无法验出纳米微粒，因此梅森大赞哥大的研究是「开创性」实验。
梅森强调，哥大研究强化了专家长久以来的建议，也就是以玻璃瓶或不锈钢容器喝水，这项建议也适用于用塑料盛装的食物及饮料。
她说：「人们不相信塑料会脱落，但它们确实会，就像我们的皮肤细胞会不断脱落一样，塑料也会不断掉落小碎片，例如当你打开超市色拉或干酪的塑料容器时。」
报导指出，专家们表示，纳米塑料是对人类健康来说，最令人忧心的塑料污染类型，因为这些微小颗粒能够入侵主要器官的细胞及组织，可能中断细胞生长过程，囤积能干扰内分泌的化学物质，例如双酚、重金属、全氟/多氟烷基物质（PFAS）等。
梅森说这些化学物质可能被带进肝脏、肾脏、大脑，甚至透过胎盘，传给母体内的胎儿。
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