科学美国人60秒 SSS Shark Fins Contain Toxic ＂One–Two Punch＂
时间：2019-01-20 作者：英语课 分类：2016年Scientific American(九)月
Living at the top of the food chain, sharks can accumulate dangerous levels of methylmercury. So much that pregnant women and children are advised not to eat shark at all. But sharks can accumulate another toxin 1 too, called BMAA, which has been linked to the development of neurodegenerative disease. Which could be bad news for shark eaters.
"Mercury in combination with BMAA is a one-two punch." Deborah Mash 2, a professor of neurology at the University of Miami's Miller 3 School of Medicine. "These are two synergistic toxins 4. So even if there are low levels of exposure from the mercury or the BMAA, when humans are exposed to both of these toxins, then they will have a synergistic effect on the nervous system."
BMAA starts out in cyanobacteria, and travels up the food chain through crabs 5 and shrimp 6 and fish. And, as previous studies have shown, all the way to sharks. What Mash and her colleagues wanted to know was how widespread the problem was, and if the chemical often appeared alongside mercury. So they analyzed 7 fin 8 and muscle samples from 10 species of shark—55 individuals in all—from the Atlantic and Pacific Oceans. And they found BMAA and mercury in all 10 species. Suggesting that exposure to that "one-two punch" could be pretty common. The results are in the journal Toxins. [Neil Hammerschlag et al., Cyanobacterial Neurotoxin BMAA and Mercury in Sharks]
It's still not clear at this point what sort of risk this occasional exposure through food might have. Still, Mash isn't waiting.
"I myself would not want to be exposed to BMAA or methyl mercury in my diet by eating shark fin or shark meat or taking shark cartilage products. We already know that mercury is toxic 9 to our health. And we already know that BMAA plus mercury is a very bad mix for the brain. So people need to be concerned, and I think that's not only for the benefit of us as consumers, but also to the poor sharks, who are threatened with extinction 10."
Conservationists have argued for years that sharks should be spared. Maybe now that it's us who are threatened... people might finally start to leave them alone.
—Christopher Intagliata
- Experts have linked this condition to a build-up of toxins in the body.专家已把这一病症与体内毒素的积累联系起来。
- Tests showed increased levels of toxin in shellfish.检验表明水生有壳动物的毒素水平提高了。
- He beat the potato into a mash before eating it.他把马铃薯捣烂后再吃。
- Whiskey,originating in Scotland,is distilled from a mash of grains.威士忌源于苏格兰，是从一种大麦芽提纯出来的。
- Every miller draws water to his own mill.磨坊主都往自己磨里注水。
- The skilful miller killed millions of lions with his ski.技术娴熟的磨坊主用雪橇杀死了上百万头狮子。
- The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
- Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》
- As we walked along the seashore we saw lots of tiny crabs. 我们在海岸上散步时看到很多小蟹。 来自《简明英汉词典》
- The fish and crabs scavenge for decaying tissue. 鱼和蟹搜寻腐烂的组织为食。 来自《简明英汉词典》
- When the shrimp farm is built it will block the stream.一旦养虾场建起来，将会截断这条河流。
- When it comes to seafood,I like shrimp the best.说到海鲜，我最喜欢虾。
- The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
- The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程，因为对他来说，爱是个不可分析的迷。 来自《简明英汉词典》
- They swim using a small fin on their back.它们用背上的小鳍游动。
- The aircraft has a long tail fin.那架飞机有一个长长的尾翼。
- 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。
- The plant is now in danger of extinction.这种植物现在有绝种的危险。
- The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。