60秒科学:Mercury Fillings Seem Safer over Time

Mercury Fillings Seem Safer over Time
A study in the journal Chemical Research in Toxicology finds that mercury on the surface of dental fillings slowly turns to an inert² sulfide compound, which should keep the mercury from harming the nervous system. Molly Webster reports

The element mercury has been shown to damage the human nervous system. Yet, since 1856, mercury amalgam³ is “the” filling dentists have used to repair our teeth. Now a study in the journal Chemical Research in Toxicology indicates that mercury fillings actually lose their toxic¹ potential over time.

Canadian scientists used x-ray spectroscopy to compare new mercury amalgams⁴ to those about 20 years old. After two decades, 95 percent of the elemental mercury on the surface of a filling had gone through a chemical reaction. It became beta-mercury sulfide, a black-colored solid. Which explains why fillings dull with age. And the compound isn’t absorbed by the body, which means it can’t affect the body the way elemental mercury can.

Of course, this study does not settle the question of how potentially harmful a new mercury filling is. But sulfide-rich foods, such as coffee, garlic and onions, may accelerate the change from metallic⁵ mercury into the safer sulfide. So if you have a new mercury filling, an odiferous chili⁶ dog with a cup of coffee may be just what the doctor ordered.
 

1 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

2 inert   

adj.无活动能力的，惰性的；迟钝的

参考例句：

• Inert gas studies are providing valuable information about other planets,too.对惰性气体的研究，也提供了有关其它行星的有价值的资料。
• Elemental nitrogen is a very unreactive and inert material.元素氮是一个十分不活跃的惰性物质。

3 amalgam   

n.混合物；汞合金

参考例句：

• To counter this myth,we explained that we're really an amalgam of little guys.为了打破这个神话，我们解释说，我们确实是由一群小小的老百姓所组成的混合体。
• American literature is to our eyes a curious amalgam of familiar and strange.我们认为，美国文学把我们所熟悉的和陌生的东西奇妙地结合起来了。

4 amalgams   

n.汞合金( amalgam的名词复数 )；混合物

参考例句：

5 metallic   

adj.金属的；金属制的；含金属的；产金属的；像金属的

参考例句：

• A sharp metallic note coming from the outside frightened me.外面传来尖锐铿锵的声音吓了我一跳。
• He picked up a metallic ring last night.昨夜他捡了一个金属戒指。

6 chili   

n.辣椒

参考例句：

• He helped himself to another two small spoonfuls of chili oil.他自己下手又加了两小勺辣椒油。
• It has chocolate,chili,and other spices.有巧克力粉，辣椒，和其他的调味品。