科學美國人60秒 | 用碳同位素驗證威士忌的真假

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This is Scientific American's 60-second Science, I'm Eliene Augenbraun.

"It came to our attention a few years ago that there were fraudulent whiskeys on the market."

Gordon Cook of the Scottish Universities Environmental Research Center.

"Scotch whiskey is Scotland's product, and we felt that being a radiocarbon laboratory in Scotland, we should take a lead on this."

Scotch whiskey is made from barley, which absorbs carbon dioxide from the air as it grows. Most of the carbon is carbon-12. But a small percentage is the radioactive isotope carbon-14, which decays at a constant, known rate— and has therefore long been used to "carbon-date" biological samples.

"Then, in the early 1950s, we had the start of the atmospheric weapons test, and these produce carbon-14. By 1960, you were twice the natural level. And '63—there was a test ban treaty, so '63 was the maximum. Since then, the level in the atmosphere has decreased as the radiocarbon goes into the biota and the oceans."

So unusually high levels of carbon-14 are associated with barley grown during the years when nuclear testing was widespread.

There's obviously a lot of money in whiskey. And some classics get bought not as imbibements but as investments. Last October, a 60-year-old 1926 bottle was auctioned off for $1.9 million.

To make sure that the stuff inside bottles of Scotch whiskey matches what's on the labels, Cook and his colleagues looked at levels of the carbon-14 in the drink. They calibrated levels of the radioactive variant of carbon in more than 200 different single-malt Scotch whiskey samples of known ages. The researchers then compared those levels to eight whiskeys claiming to have been bottled from 1847 to 1978.

"We haven't found any whiskeys purported to be from the 19th century that are genuine."

Because those allegedly 19th-century bottles contained material clearly produced during the nuclear-testing era. The study is in the journal Radiocarbon.

Cook hopes these verification techniques will help keep the whiskey business true to the words of Robert Burns: "Here's a bottle and an honest friend."

For Scientific American's 60-second Science. I'm Eliene Augenbraun.

參考譯文

這裏是科學美國人――60秒科學系列，我是艾琳·奧根布勞恩。

“市場上存在假威士忌，這在幾年前引起了我們的注意。”

蘇格蘭大學環境研究中心的戈登·庫克説到。

“蘇格蘭威士忌是蘇格蘭的產品，作為蘇格蘭的放射性碳實驗室，我們應該帶頭研究這個問題。”

蘇格蘭威士忌由大麥製成，而大麥在生長過程中會吸收空氣中的二氧化碳。其中大部分碳是碳12。而放射性同位素碳14只佔一小部分，它以一種已知的恆定速率衰變，因此長期以來一直被用於生物樣品的“碳素年齡測定”。

“之後在上世紀50年代初，我們開始進行太空武器測試，這會產生碳14。到1960年，大氣中的碳14含量為自然水平的兩倍。但1963年出台了禁止試驗條約，因此碳14含量在該年達到最大值。從那以後，隨着放射性碳進入生物區和海洋，大氣中的碳14含量逐漸下降。”

因此，碳14水平異常高與在核試驗擴散年代生長的大麥有關。

顯然，威士忌中有大量金錢。一些經典威士忌被購買並不是為了飲用，而是為了投資。去年10月，一瓶有1926年生產的60年威士忌以190萬美元的價格被拍賣。

為了確保蘇格蘭威士忌酒瓶中的物質與標籤相符，庫克和同事查看了酒中的碳14含量。他們校準了200多種已知年份的單一麥芽蘇格蘭威士忌樣品中的放射性碳變種水平。之後，研究人員將這些含量與聲稱於1847年到1978年間裝瓶的8種威士忌進行了比較。

“就這些聲稱產於19世紀的威士忌而言，我們尚未發現任何一瓶是真貨。”

因為那些聲稱是19世紀的酒瓶裏，明顯含有產於核試驗時期的物質。這項研究發表在《放射性碳》期刊上。

庫克希望這些驗證技術能幫助威士忌酒廠忠於羅伯特·伯恩斯的名言：“這是一個瓶子和一位誠實的朋友。”

謝謝大家收聽科學美國人——60秒科學。我是艾琳·奧根布勞恩。

重點講解：

1. be made from （由…）構成的；（由…）製成的；

Wine is made from grapes.

葡萄酒是用葡萄做的。

2. be associated with 有關聯的；相關的；

This syndrome is associated with frequent coughing.

這種綜合徵與經常咳嗽有關。

3. auction off 拍賣掉；

Her dresses will be auctioned off for charity.

她的衣物將被拍賣以資助慈善事業。

4. make sure 一定要；設法保證；

Please make sure all mobile phones are switched off during the performance.

請確保演出時關上所有手機。