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The average liter of bottled water has nearly a quarter million invisible pieces of very small plastic known as nanoplastics, a recent study says.
最近的一项研究表明，每升瓶装水中平均含有将近二十五万个微小塑料颗粒，被称为纳米塑料。
Researchers found the nanoplastics with a microscope using dual lasers.
研究人员使用双激光显微镜发现了这些纳米塑料。
Scientists long figured there were lots of these very small plastic pieces. But until researchers at Columbia and Rutgers universities did their calculations, they never knew how many or what kind.
科学家们长期以来一直认为存在大量这些非常小的塑料颗粒。但在哥伦比亚大学和罗格斯大学的研究人员进行计算之前，他们不知道有多少，或者是什么类型的颗粒。
Looking at five samples each of three common bottled water brands, researchers found particle levels ranged from 110,000 to 400,000 per liter. The average was around 240,000, the study said. The research appeared recently in the publication Proceedings of the National Academy of Sciences.
研究人员观察了三个常见瓶装水品牌的每个五个样本，发现每升的微粒水平在11万到40万之间。研究称，平均水平约为24万。这项研究最近发表在《美国国家科学院院刊》上。
Nanoparticles are particles that are less than a micron in size. In comparison, a human hair is about 83 microns wide.
纳米粒子是指直径小于一微米的颗粒。相比之下，人类的头发宽约83微米。
Previous studies have looked at slightly bigger microplastics that range from 5 millimeters, which could be seen by human eyes, to one micron. About 10 to 100 times more nanoplastics than microplastics were discovered in bottled water, the study found.
先前的研究主要关注略大一点的微塑料，其直径范围从5毫米（可见于人眼）到一微米。研究发现，与微塑料相比，瓶装水中发现的纳米塑料数量大约是微塑料的10到100倍。
Much of the plastic seems to be coming from the bottle and the filtration system to clean the water itself, said the study’s lead writer Naixin Qian of Columbia University.
该研究的主要作者、哥伦比亚大学的钱乃新表示，许多塑料似乎来自瓶子和用于清洁水的过滤系统。
She would not name the three brands because researchers want more samples and they want to study more brands. Still, she said they were common and bought at a Walmart, a popular store in the U.S.
她不愿透露这三个品牌的名称，因为研究人员希望获得更多的样本，并研究更多的品牌。但她表示，这些品牌是常见的，可以在美国的沃尔玛等大型商店购买到。
Researchers still cannot answer the big question: Are those nanoplastic pieces harmful to health?
研究人员仍然无法回答一个重要问题：这些纳米塑料颗粒对健康是否有害？
“That’s currently under review. We don’t know if it’s dangerous or how dangerous,” said study co-writer Phoebe Stapleton of Rutgers University. “We do know that they are getting into the tissues (of mammals, including people) … and the current research is looking at what they’re doing in the cells.”
罗格斯大学的研究合著者菲比·斯特普顿表示：“目前正在评估。我们不知道它是否危险，以及有多危险。我们知道它们正在进入哺乳动物（包括人类）的组织中……当前的研究正在研究它们在细胞中的作用。”
The International Bottled Water Association said in a statement: “There currently is both a lack of standardized (measuring) methods and no scientific” agreement on the possible health effects of nano- and microplastic particles. The statement added, “Therefore, media reports about these particles in drinking water do nothing more than unnecessarily scare consumers.”
国际瓶装水协会在一份声明中表示：“目前缺乏标准化（测量）方法，对纳米和微塑料颗粒的潜在健康影响也没有科学上的一致意见。”声明还补充说：“因此，关于这些颗粒在饮用水中的媒体报道只会毫无必要地吓唬消费者。”
The American Chemistry Council, which represents plastics manufacturers, declined to immediately comment.
代表塑料制造商的美国化学协会拒绝立即置评。
The Associated Press spoke with four co-writers of the study. All of them said they would cut back on their bottled water use.
美联社采访了该研究的四位合著者。他们都表示将减少瓶装水的使用。
Columbia chemist Wei Min said he has reduced his bottled water use by half. Stapleton said she now depends more on filtered water at home in New Jersey.
哥伦比亚大学的化学家魏敏表示，他已经将瓶装水的使用减少了一半。斯特普顿表示，她现在更依赖新泽西州家中的过滤水。
But study co-author Beizhan Yan, a Columbia environmental chemist who increased his tap water usage, pointed out that filters themselves can be a problem by introducing plastics.
但是，研究合著者、哥伦比亚大学的环境化学家严倍
战表示，他增加了自来水的使用量，指出过滤器本身可能会引入塑料问题。
“There’s just no win,” Stapleton said.
斯特普顿表示：“这根本没有好办法。”
Outside experts, who praised the study, agreed that there is a general unease about the risks of fine plastic particles. Still, it is too early to say anything certain about the risks.
赞扬这项研究的外部专家们一致认为，人们对细小塑料颗粒的风险普遍感到不安。然而，现在说什么关于风险的确切结论还为时过早。
“The danger of the plastics themselves is still an unanswered question. For me, the additives are the most concerning,” said Jason Somarelli of Duke University in North Carolina. Somarelli was not part of the research. He added, “We and others have shown that these nanoplastics can be internalized into cells, and we know that nanoplastics carry all kinds of chemical additives that could cause cell stress, DNA damage and change metabolism or cell function.”
北卡罗来纳州杜克大学的杰森·索马雷利表示：“塑料本身的危险仍然是一个未解之谜。对我来说，添加剂是最令人担忧的。”索马雷利并未参与这项研究。他补充说：“我们和其他人已经证明了这些纳米塑料可以被细胞内化，而我们知道纳米塑料携带了各种可能引起细胞压力、损伤DNA并改变新陈代谢或细胞功能的化学添加剂。”
Dual laser microscope
双激光显微镜
About 15 years ago, Min invented dual laser microscope technology that identifies specific compounds by their chemical properties and how they respond when exposed to lasers. Yan and Qian talked to him about using that technique to find and identify plastics that had been too small for researchers using established methods.
大约15年前，魏敏发明了一种双激光显微镜技术，通过化学性质以及在激光照射下的响应方式来识别特定的化合物。严倍战和钱乃新与他讨论了使用该技术寻找和鉴定那些对于使用传统方法的研究人员来说太小的塑料颗粒。
Kara Lavender Law of the Sea Education Association said “the work can be an important advance in the detection of nanoplastics,” but she said she’d like to see other chemists use the technique and get the same results.
海洋教育协会的卡拉·拉温德·劳表示，“这项工作可能在纳米塑料检测方面取得重要进展”，但她表示她希望看到其他化学家使用这一技术并取得相同的结果。
Yan said he is starting to study water supplies in the U.S. cities of Boston, St. Louis, Los Angeles and elsewhere to see how much plastics are in their tap water. Previous studies looking for microplastics and some early tests suggest there may be less nanoplastic in tap water than in bottled water.
严倍战表示，他开始研究美国波士顿、圣路易斯、洛杉矶等城市的供水情况，以了解他们的自来水中含有多少塑料。先前的研究寻找微塑料和一些早期的测试表明，自来水中的纳米塑料可能比瓶装水少。
Even with unknowns about human health, Yan said he does have one suggestion: Use reusable bottles instead of single-use plastics.
尽管对于人类健康仍有未知因素，但严倍战表示他有一个建议：使用可重复使用的瓶子，而不是一次性塑料。
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Words in This Story
sample – n. an amount of something that gives you information about the thing it was taken from
brand -- n. a category of products that are all made by a particular company
review -- v. to look at or examine (something) carefully especially before making a decision or judgment
standardize – v. to change (things) so that they are similar and consistent
tap water – n. water that comes through pipes from the public water system
internalize -- v. to absorb or take in
metabolism -- n. the chemical processes by which a plant or an animal uses food or water to make energy
detect -- v. to discover or notice the presence of something
