如果你吃了铀怎么办?

如果你吃了铀怎么办?

Scan the periodic table and you'll spot a lot of the same words you'd find on an FDA food label: potassium, iron, calcium. But look on the bottom row, and you'll see something you're more likely to associate with news about nuclear accords than a box of breakfast cereal: uranium. You can't help but wonder — what if you picked up a spoonful and started eating?

扫描周期表，你会发现很多和FDA食品标签上的相同的单词：钾，铁，钙。但看看最下面一排，你会发现，比起一盒早餐麦片，你更可能联想到有关核协议的新闻：铀。你不禁要问——如果你拿起一勺开始吃呢?

Let's back up and take a closer look at atomic number 92. Uranium is a dense, weakly radioactive metal that's naturally found in soil, rock and water. After mining uranium from the ground, experts manipulate its three isotopes to produce depleted and enriched variations; the former is less radioactive and used to make bullets and armor plating, while the latter is used in nuclear weapons and power plants.

我们回过头来，仔细看看92号原子。铀是一种致密的、弱放射性的金属，天然存在于土壤、岩石和水中。在从地面开采铀之后，专家们操纵它的三种同位素产生贫化和浓缩的变化;前者放射性较低，用于制造子弹和装甲板，而后者则用于核武器和核电站。

But you don't have to work in defense manufacturing or in a place equipped with cooling towers to be exposed to uranium. In fact, eating uranium is one of the most common means of exposure. Crops like potatoes and turnips are among the most uranium-rich foods in our diet, but they aren't the only ones: According to the Environmental Protection Agency, the average person eats 0.07 to 1.1 micrograms of uranium per day [source: EPA].

你不必在国防制造业工作，也不必在一个装备有冷却塔的地方接触铀。事实上，吃是最常见的接触方式之一。土豆和萝卜等作物是我们饮食中最富含铀的食物之一，但它们并不是唯一的：根据环境保护署的数据，普通人每天摄入0.07至1.1微克铀[来源：环保署]。

The good news is you don't have to abstain from root vegetables anytime soon. That daily uranium consumption isn't nearly enough to be harmful, especially since your body has a hard time absorbing uranium as it is [source: Keith et al]. Between 95 and 99 percent of the uranium you ingest is excreted in feces, and you urinate 70 percent of the rest within 24 hours [source: ATSDR]. A small amount of uranium will stay in your bones anywhere from months to years after ingestion, but eating uranium is much less toxic than inhaling it.

好消息是你不必在短期内戒掉根类蔬菜。每天摄入的铀还不足以造成危害，特别是因为你的身体很难像现在这样吸收铀[来源：Keith等人]。你摄入的铀有95%到99%在粪便中排出，其余70%在24小时内排尿[来源：美国毒物与疾病登记署]。少量的铀会在摄入后的几个月到几年内留在你的骨头里，但是吃铀的毒性比吸入铀的毒性小得多。

But what if, instead of being a trace element in the food on your plate, uranium is the main course? You might not be surprised to learn that eating large doses of a radioactive substance leads to an increased chance of developing a cancer. But long-term concerns about radiation exposure pale in comparison to the immediate effects of chemical toxicity. Uranium mainly targets the kidneys: Damage starts to appear after taking in 25 milligrams, while intakes of more than 50 milligrams can cause renal failure and death [source: Argonne National Laboratory]. Additionally, studies of rats that ingest uranium over long periods of time have shown changes in brain chemistry [source: ATSDR].

但如果铀不是你盘子里食物中的微量元素，而是主菜呢?当你得知吃大剂量的放射性物质会增加患癌症的几率时，你可能不会感到惊讶。但与化学毒性的直接影响相比，长期以来人们对辐射暴露的担忧显得苍白无力。铀主要以肾脏为目标：摄入25毫克铀后开始出现损害，而摄入超过50毫克铀会导致肾衰竭和死亡[来源：阿贡国家实验室]。此外，对长期摄入铀的大鼠的研究表明，它们的大脑化学成分发生了变化[来源：美国毒物与疾病登记署]。

Fortunately, while there's plenty of reason to believe uranium is lethal in high doses, there are no known human deaths from "oral exposure" to uranium [source: Keith et al]. Still, instead of eating the kind of yellowcake that's made with uranium ore, you're better off sticking with the kind of cake you top with chocolate frosting.

幸运的是，虽然有足够的理由相信高剂量的铀是致命的，但目前还没有人因“口服”铀而死亡[来源：Keith等人]。不过，与其吃那种用铀矿石做成的黄蛋糕，不如坚持吃那种上面涂有巧克力糖霜的蛋糕。