彭蒙惠英语：The Mercury Mess（在线收听） |
|
The Mercury Mess By Samantha Levine / © 2004, as first appeared in U.S. News & World Report. All rights reserved with permission. Distributed by Tribune Media Services International. What are the dangers of mercury in fish? Can the mercury mess be cleaned up? 1 Are these fish safe to eat?” It’s a question being asked by customers who buy fish directly from fishing boats and local food store patrons alike. Because the reality is that these days your favorite fish may come with a side of toxic mercury. Recently the U.S. Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) warned that consumers at high risk should cut back on eating canned tuna, eating no more than one 6-ounce can of albacore per week. Swordfish, shark and several other fish are also off-limits for young children and women who are pregnant, nursing or planning to conceive. Why? High mercury levels can cause learning problems or retardation in children and neurological damage in developing fetuses. Where does it come from? Over 1,000 coal-burning power plants are the main uncontrolled source of mercury pollution in the United States. As coal burns, it releases traces of mercury that waft out of smokestacks. Much of the mercury stays airborne for up to two years and spreads around the globe. But some is emitted as a water-soluble compound formed when mercury reacts with chlorine, an element often found in coal from the eastern United States. How does mercury get into fish? Precipitation quickly washes this form of mercury into lakes, rivers and oceans, where microorganisms take it up and convert it into toxic methylmercury. The mercury then passes up the food chain into fish—reaching the highest levels in large predatory species like swordfish and tuna—and on into people.
Vocabulary Focus side (n) [said] extra, often referring to food; a small serving off-limits (adj) [5C:f 7limits] forbidden, usually from entering a place waft (v) [wB:ft] to move gently through the air water-soluble (adj) [5wC:tE7sCljubl] relating to something that can be dissolved in water Specialized Terms mercury (n) 汞 a heavy, silver-colored metal that is liquid at ordinary temperatures albacore (n) 长鳍鲔 a large type of tuna fish that is used most often for canned tuna neurological (adj) 神经性的，与神经有关的 relating to nerves and the brain methylmercury (n) 甲基 a toxic compound of mercury formed when mercury bonds with microorganisms food chain (n phr) 食物链 a series of living things that are connected because each group of things eats the group below it in the series
汞污染 含汞的鱼会带来什么样的危险？汞污染可以被清除吗？ 陈小欣 译 1 “食用这些鱼安全吗？”这是顾客向渔船或当地食品店直接购买鱼时提及的问题。因为事实上，现在你最喜欢吃的鱼，都可能含有毒性的汞。 近来美国环保局和食品及药物管理局警告处于高危险群的消费者，应减少食用罐装鲔鱼，每周食用不超过一罐以上的6盎司装罐头长鳍鲔鱼。对于幼儿及怀孕、哺乳中或计划生育的妇女，也禁止食用剑鱼、鲨鱼和另外几种鱼类。为什么呢？因为高含量的汞会导致儿童学习上的困难及障碍，并且对发育中的胎儿造成神经性的损伤。 它从何处而来？ 超过1000家以上的燃煤发电厂，是美国最主要未被控制的汞污染来源。煤燃烧时所释出微量的汞会飘出烟囱。大量的汞会停留在空中长达两年，并扩散至全球各地。有些则与来自美国东部的煤中常见的成分——氯，发生化学反应，形成一种水溶性的化合物。 汞如何进到鱼体内？ 随着雨、雪的降下，这种型态的汞很快就被冲进了湖泊、河流和海洋。微生物从这些地方把它吃了下去，而且转变为有毒的甲基。而汞也就随着食物链进到鱼体里面，一路抵达最高等的大型肉食鱼类，像剑鱼和鲔鱼，然后进入人体。 |
| 原文地址：http://www.tingroom.com/lesson/pengmenghui/26522.html |