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Look around you -- how much plastic is within reach? Plastic is literally everywhere.
看看你周围，有所少塑料触手可及？塑料无处不在。
Seriously, scientists have found it in the deepest depths of the ocean and on top of the most remote mountain peaks.
严肃来讲，科学家们已经在海洋最深处以及最偏远山峰之顶发现了塑料。
Since the end of World War II, we've produced more than eight billion metric tons of plastic.
自从第二次世界大战结束以来，我们人类已经生产了超过80亿公吨的塑料。
Of all that, only about 9% has ever been recycled. But it's not just that humans are lazy or bad.
在所有这些塑料中，只有9%被回收利用。但这不只是因为人类懒惰或坏。
So let's take a look at what makes something that's so vital to modern life also difficult to reuse.
所以让我们来看看是什么让这个对现代生活如此重要的东西也难以重复使用。
Think about a plastic water bottle, like the kind you might buy at an airport.
想想塑料水瓶，就像你在机场买的那种。
It's estimated that around the world, people buy a million plastic bottles every minute.
据估计，在世界各地，人们每分钟就会购买100万个塑料瓶。
And it's easy to think of a "plastic bottle" as being made of a single thing, which is the first problem.
人们很容易认为一个“塑料瓶子”是由单一材料制成的东西，这是第一个问题。
We use the generic word plastic to refer to a bunch of chemicals that are actually really different.
我们用“塑料”这个通用词来指代一堆实际上非常不同的化学物质。
Broadly speaking, plastics are polymers, which is a fancy way of saying they're repeating chains of molecules.
从广遇上来讲，塑料是聚合物，也就是说它们是重复的分子链。
During their formation, they can be processed into arbitrary shapes,
在它们的形成过程中，它们可以被加工成任意的形状，
which is what gives them such a wide range of applications.
这就赋予了它们广泛的用途。
Now, every plastic material falls into one of two groups, thermoplastics and thermosets.
现在每种塑料材料都被分成两类：热塑性塑料和热固性塑料。
The individual links in a thermoplastic are held together by relatively weak chemical bonds.
热塑性塑料中的各个链环是由相对较弱的化学键连接在一起的。
When the material is reheated, the molecules can break free from those bonds and take on a new shape.
当塑料被重新加热，分子可以从那些化学键中分解出来并呈现出新的形状。
In a thermoset, the polymer chains form intricate networks with tight bonds.
在热固性塑料中，聚合物链与紧密键形成复杂的网络。
Heating these materials enough to break the network destroys the plastic itself.
将这些材料加热到足以破坏塑料网的程度，就会破坏塑料本身。
So while thermosets can be very strong, they can be difficult to recycle.
因此，虽然热固性塑料很强，但它们很难回收。
There are a lot of different types of thermoplastics in commercial products,
商品中有很多不同类型的热塑性塑料，
but two of the ones most commonly seen in the United States are known as PET and HDPE.
但在美国有两种最常见的热塑性塑料—PET和HDPE。
Polyethylene terephthalate, or PET, is clear, can withstand moderate temperatures, and resists cracking.
聚对苯二甲酸乙二醇酯（PET）是透明的，可以承受适度的温度，且防裂。
High-density polyethylene, or HDPE, can survive more extreme temperatures but generally lacks the transparency of PET.
高密度聚乙烯（HDPE）能在更极端的温度下存活，但通常缺乏PET的透明度。
Both of these plastics are used for ordinary bottles.
这两种塑料都用于普通的瓶子。
But the trouble is, not all recycling centers accept both of them.
但问题是，并不是所有的回收中心都接受这两种塑料。
So you need to know what kind of plastic you're tossing out—
所以你需要知道你扔掉的是哪种塑料—
and what types your local recycler accepts— in order to dispose of one correctly.
以及你当地的回收站接受哪种类型的塑料—这样才能正确的处理。
Even then, you're probably still doing it wrong, because a single product often combines multiple kinds of plastic.
即便如此，你可能还是做错了，因为一件产品往往包含多种塑料。
For instance, the twist cap on that bottle made of PET can often be made of polypropylene, yet another type of plastic.
例如，PET瓶上的拧盖通常可以由聚丙烯制成，而聚丙烯是另一种塑料。
Since most of us don't carefully disassemble our trash before getting rid of it,
由于我们大多数人在扔掉垃圾之前都不会仔细地把它们拆开，
recycling plants need a way to separate all the plastics they receive.
所以回收工厂需要一种方法来把它们收到的所有塑料分开。
And it can be critical for this separation to be nearly perfect.
这种分离要接近完美，这点是很关键的。
For example, if the plastic PVC gets recycled, it can create acids that damage and discolor PET beyond repair.
例如，如果塑料PVC被回收，它会产生酸，损坏并使PET褪色且无法修复。
And all it takes is a single PVC bottle in a pallet of 10,000 PET ones to ruin the whole batch.
而这一切只需要一万个PET瓶中有一个PVC瓶子，就可以破坏整个批次。
To avoid these problems, recycling plants have a few ways to sort plastics.
为了避免这些问题，回收厂有几种方法分类塑料。
One approach is to use density, when immersed in water, PET sinks while some other plastics float.
一种方法是利用密度，当PET浸入水中时，它会下沉，而其他一些塑料会漂浮。
Another option is heat. Different plastics become soft at different temperatures,
另一个方法是加热。不同的塑料会在不同的温度下变柔软，
so precisely heating the mixture can set the various materials apart.
所以准确地加热混合物可以把不同的材料分开。
But since even a tiny bit of contamination can do a lot of damage,
但是，由于即使一点点的污染也会造成很大的损害，
recycling properly gets expensive— sometimes too expensive to be worthwhile.
回收利用的成本就会变得很高——有时会高得不值得。
For instance, in New York City, every ton of recyclables costs $200 dollars more to recycle than it would cost to toss in a landfill.
例如，在纽约市，每吨可回收材料的回收成本比扔进垃圾填埋场要多200美元。
But here's the thing even if we invented a process that magically
但问题是，即使我们发明了一种神奇
and flawlessly sorted and processed every kind of plastic, recycling it would still be hard.
且完美的分类和处理每一种塑料的方法，回收仍然很困难的。
That's because, unlike metal and glass, plastic degrades every time you recycle it.
这是因为，与金属和玻璃不同，塑料在每次回收时都会降解。
Aluminium, for instance, is an element, so no matter how many times you melt and rework it,
例如，铝是一种元素，所以不管你熔化加工多少次，
you've still just got aluminium atoms. On the other hand, at the microscopic level,
你得到的仍然是铝原子。另一方面，在微观层面上，
plastics are really long chains of molecules. For example, HDPE, one of the plastics we do recycle,
塑料是很长的分子链。例如，HDPE，是我们回收的一种塑料，
can contain up to 100,000 linked ethylene molecules. Every time a plastic is reheated to form it into something new,
可含有多达10万个链接乙烯分子。每当塑料被重新加热形成新的东西时，
some of those chains break, reducing the quality of the material.
其中一些链断裂，降低了材料的质量。
To get around this, manufacturers add new plastic to the mixture, so even recycling plastic requires new plastic.
为了解决这个问题，制造商在混合物中添加了新的塑料，所以即使回收塑料也需要新的塑料。
Another technique for prolonging the life of plastic is down-cycling,
另一种延长塑料寿命的技术是降级循环，
which turns the material into increasingly less sophisticated products.
这将使塑料变成越来越简单的产品
Plastic that starts as a water bottle might then be turned into fleece for a jacket before ending its life as plastic lumber in a deck.
塑料一开始是一个水瓶，然后可能变成羊毛夹克，最后以甲板上的塑料木材作为生命的终结。
Eventually, even that isn't enough, and whatever's left gets burned for energy or thrown into a landfill.
最终，即使这还不够，剩下的东西会被燃烧用作能源或者被扔进垃圾填埋场。
So, in a sense, there is no such thing as plastic recycling, every bit of plastic ever made will eventually end up as waste.
所以，在某种意义上，没有塑料回收这回事，每一块塑料最终都会变成废物。
And in many cases, it's not possible to do even one round of recycling.
在很多情况下，即便是做一轮回收都不可能。
That's a big deal considering that, in 2009, about 4% of all the oil and gas extracted worldwide was turned into plastic.
考虑到2009年全球约4%的石油和天然气被提炼成塑料，这可是一件大事。
And another 3 or 4% was used to create the energy for that production.
另外的3%或4%被用来为生产提供能量。
Now, people probably aren't going to give up plastic and there are some good reasons to keep it around.
现在，大家可能不会放弃塑料，有一些很好的理由能将它留下。
It has huge benefits for health, accessibility, and food safety. But we can be better about how we use it.
它对健康、可及性和食品安全都有巨大的好处。但我们可以更好地利用它。
And that means developing new recycling techniques that prolong the life of the plastic we have,
这意味着开发新的回收技术，延长我们现有塑料的使用寿命，
cutting out single-use products where we can, and being careful about which plastics we use and how we combine them.
尽可能减少使用一次性产品，并对我们使用的塑料种类和使用方式小心谨慎。
To find out more about what happens behind the scenes to the plastic you recycle, check out the episode after this.
想要了解更多关于回收塑料的幕后故事，请看下期。
