塑料的危害

Plastic is everywhere: water bottles, dental sealant, the odd floating trash island. Over the years, researchers have raised the alarm about how chemicals from plastics might affect human health, often focusing on one chemical in particular: bisphenol A (BPA).

塑料无处不在：水瓶、牙科密封剂、怪异的浮动垃圾岛。多年以来，研究员就塑料中的化学物质或影响人类健康提出了警告，尤为关注双酚A（BPA）这一化学物质。

BPA is used to make a hard, clear type of plastic called polycarbonate. It's so ubiquitous that a 2009 study conducted by the Centers for Disease Control found that of the 2,517 people they tested, nearly all of them had detectable levels of BPA in their urine. New research hints that BPA-free plastic alternatives may not actually be any safer.

BPA被用来制作硬质透明型塑料，这种塑料被称为聚碳酸酯。BPA遍地都是，2009年疾病预防控制中心开展的一项研究发现：在2517位受试者中，几乎所有人的尿液都可检测到BPA。新研究表明不含BPA的塑料替代品可能也并不安全。

It all started 20 years ago, when researchers in the lab of geneticist Patricia Hunt realized that something was very wrong with their mice.

这一切始于20年前，当时遗传学家帕特里夏·亨特（Patricia Hunt）实验室的研究员意识到：他们的小鼠有问题。

The process of making a healthy egg cell involves a series of cell divisions, during which chromosomes (the long strands of DNA that make up an organism's genome) are divided up into the newly-formed cells. If something goes wrong and the cells end up with an abnormal number of chromosomes, that's usually a very serious problem.

制造健康卵细胞的过程包括一系列的细胞分裂，在此过程中，染色体（构成生物体基因组的长链DNA）会被分开形成新的细胞。如果出现问题，细胞的最终染色体数量便会异常，通常是一个非常严重的问题。

The researchers in Hunt's lab were studying this process when suddenly the egg cells of their mice--including the ones that were supposed to be normal--started showing major genetic abnormalities. Something in the environment of these mice was causing their egg cells to have problems dividing. It turned out that the problem was the plastic cages.

当时，亨特实验室的研究员正在研究该过程，突然间，小鼠的卵细胞--包括本该正常的小鼠--开始显现主要的遗传异常。这些小鼠所处环境的某些因素导致了它们的卵细胞分裂有问题。结果发现：这一因素是塑料笼。

The mice were living in cages made of polycarbonate. A worker had accidentally used a harsh detergent to clean them, which caused them to release BPA. When the researchers replaced the cages, the egg cells went back to normal, and when they tried giving the mice BPA on purpose, the egg cells had the same problems as before. The researchers concluded that BPA is capable of causing genetic abnormalities in mice.

这些小鼠被关在由聚碳酸酯制成的笼子里。一位工作人员不小心使用了强效清洁剂清洁笼子，从而导致BPA的释放。当研究员替换这些笼子后，小鼠的卵细胞重新回归正常。但当他们有目的地给这些小鼠释放BPA时，它们的卵细胞又出现了与之前一模一样的问题。研究员得出结论：BPA这一化学物质会导致小鼠遗传异常。

So, does this mean we should all go home and throw out all our plasticware? Maybe, maybe not. Humans have different metabolisms than mice, so it's completely possible that consuming the same substance could have a different impact on us, or have no impact at all.

所以，这是否意味着我们应该赶紧回家，扔掉所有的塑料制品？也许是，也许不是。人类的新陈代谢与小鼠不同，所以摄入同样的物质可能会对我们产生完全不同的影响，甚至一点儿影响都没有。