In recent years， there has been rising concern that tiny particles known as microplastics are showing up basically everywhere on Earth， from polar ice to soil， drinking water and food. Formed when plastics break down into progressively smaller bits， these particles are being consumed by humans and other creatures， with unknown potential health and ecosystem effects. One big focus of research： bottled water， which has been shown to contain tens of thousands of identifiable fragments in each container.

近些年，微塑料逐渐引起人们的担忧——从极地冰川到土壤、饮用水和食物，这种微粒在地球上几乎无处不在。微塑料是塑料在逐步分解的过程中形成的小颗粒，能被人和其他生物摄入，对人体健康和生态系统有何潜在影响尚不清楚。相关研究的一大焦点是瓶装水，已发现每瓶水中含有数万个可辨别的塑料碎片。

Now， using newly refined technology， researchers have entered a whole new plastic world： the poorly known realm of nanoplastics， the spawn1 of microplastics that have broken down even further. For the first time， they counted and identified these minute particles in bottled water. They found that on average， a liter contained some 240，000 detectable plastic fragments—10 to 100 times greater than previous estimates， which were based mainly on larger sizes.

如今，借助改进的技术，研究人员得以涉足鲜为人知的塑料新世界：纳米塑料领域。纳米塑料是微塑料进一步分解的产物。研究人员首次对瓶装水中的这种极小微粒进行了辨别和计数。他们发现，平均每升瓶装水中可检测出的塑料碎片约24万个，是以往主要基于较大尺寸颗粒的估值的10倍到100倍。

The study was published in the journal Proceedings of the National Academy of Sciences.

相关研究成果已发表在美国的《国家科学院院刊》上。

Nanoplastics are so tiny that， unlike microplastics， they can pass through intestines and lungs directly into the bloodstream and travel from there to organs including the heart and brain. They can invade individual cells， and cross through the placenta to the bodies of unborn babies. Medical scientists are racing to study the possible effects on a wide variety of biological systems.

与微塑料不同，纳米塑料小到足以穿过肠道和肺部直接进入血液，然后随血液抵达心脏和大脑等器官。它们甚至能侵入单个细胞，经由胎盘进入胎儿体内。医学家们正在加紧研究纳米塑料可能对各种生物系统造成的影响。

“Previously this was just a dark area， uncharted. Toxicity studies were just guessing what’s in there，” said study coauthor Beizhan Yan， an environmental chemist at Columbia University’s Lamont-Doherty Earth Observ-atory. “This opens a window where we can look into a world that was not exposed to us before.”

“以前，纳米塑料领域是一个盲区。毒性研究也只能猜测里面有什么。”研究论文合著者颜备战表示，他是哥伦比亚大学拉蒙特-多尔蒂地球观测所的环境化学家，“现在，这项研究打开了一扇窗，透过它我们能一窥未曾探索过的世界。”

Worldwide plastic production is approaching 400 million metric tons a year. More than 30 million tons are dumped yearly in water or on land， and many products made with plastics including synthetic textiles shed particles while still in use. Unlike natural organic matter， most plastics do not break down into relatively benign2 substances; they simply divide and redivide into smaller and smaller particles of the same chemical composition. Beyond single molecules， there is no theoretical limit to how small they can get.

目前，塑料的全球年产量直逼4亿吨。