科學家預測南極大型冰川消失的速率將會變得更快

原文網址：www.sciencedaily.com/releases/2016/05/160518133819.htm

Scientists predict extensive ice loss from huge Antarctic glacier

科學家預測南極大型冰川消失的速率將會變得更快

Current rates of climate change could trigger instability in a major Antarctic glacier, ultimately leading to more than 2m of sea-level rise.

現行的氣候變遷速率會造成南極的一條主要冰川變得相當不穩定，最終可能導致海面上升超過2公尺。

This is the conclusion of a new study looking at the future of Totten Glacier, a significant glacier in Antarctica. Totten Glacier drains one of the world's largest areas of ice, on the East Antarctic Ice Sheet (EAIS).

對托滕冰川(Totten Glacier)的未來命運進行的新研究導出了上述結論。托滕冰川是一條位於南極洲的大型冰川，它流經全世界最大的冰原之一—東南極冰原( East Antarctic Ice Sheet, EAIS)。

By studying the history of Totten's advances and retreats, researchers have discovered that if climate change continues unabated, the glacier could cross a critical threshold within the next century, entering an irreversible period of very rapid retreat.

研究人員藉由探討托滕冰川前進和後退的歷史，發現如果氣候變遷在未來仍未減緩，托滕冰川可能會在下個世紀內跨過一道臨界值，而進入再也無法挽回的極端快速消融期。

This would cause it to withdraw up to 300 kilometres inland in the following centuries and release vast quantities of water, contributing up to 2.9 metres to global sea-level rise.

這會造成托滕冰川在下個世紀往內陸退縮長達300公里並且融化出大量的淡水，導致全球海平面上升2.9公尺之多。

The EAIS is currently thought to be relatively stable in the face of global warming compared with the much smaller ice sheet in West Antarctica, but Totten Glacier is bucking the trend by losing substantial amounts of ice. The new research reveals that Totten Glacier may be even more vulnerable than previously thought.

在面臨全球暖化的威脅時，相較位在西南極面積小了許多的冰原來說，目前認為東南極冰原是較為穩定的地區。然而與此趨勢相反，托滕冰川其實已經流失了大量冰雪。新研究顯示跟我們過往認為的相比，托滕冰川實際上可能更加脆弱。

The study, by scientists from Imperial College London and institutions in Australia, the US, and New Zealand is published today in Nature. Last year, the team discovered that there is currently warm water circulating underneath a floating portion of the glacier that is causing more melting than might have been expected.

這篇今日刊登於期刊《自然》(Nature)的新研究由倫敦帝國學院以及澳洲、美國和紐西蘭學術機構的科學家進行。研究團隊去年發現在冰河漂浮於海面的部分的下方，目前於此循環的暖水融化冰河的能力可能比我們預期中還要超出許多。

Their new research looks at the underlying geology of the glacier and reveals that if it retreats another 100-150 km, its front will be sitting on an unstable bed and this could trigger a period of rapid retreat for the glacier. This would cause it to withdraw nearly 300 km inland from its current front at the coast.

他們的新研究著眼於托滕冰河之下的地質，並且發現如果冰河再繼續往後消退100至150公里，則它的前緣將會落在一個不穩定岩盤之上，這可能造成冰河進入一段快速消融期。結果將會使目前位於海岸附近的冰河前緣往內陸退縮將近300公里。

Retreating the full 300 km inland may take several hundred years, according to co-author Professor Martin Siegert, Co-Director of the Grantham Institute at Imperial College London. However, once the glacier crosses the threshold into the unstable region, the melting will be unstoppable -- at least until it has retreated to the point where the geology becomes more stable again.

根據倫敦帝國學院葛拉森研究所的共同作者 Martin Siegert教授所言，托滕冰河要往內陸後退整整300公里大概需要數百年的時間。然而，一旦冰河跨越臨界值而進入不穩定狀態，融化的趨勢就會變得銳不可擋—至少要等到冰河後退至地質再次穩定的地區為止。

"The evidence coming together is painting a picture of East Antarctica being much more vulnerable to a warming environment than we thought," he said. "This is something we should worry about. Totten Glacier is losing ice now, and the warm ocean water that is causing this loss has the potential to also push the glacier back to an unstable place."

「我們結合所有證據描繪出來的圖像顯示，在日趨暖化的環境下南極大陸東部跟我們過往認知中相比，實際上更為脆弱。」他說。「這確實是件我們應該要憂心的事情。托滕冰河的冰雪正不斷流失，而身為罪魁禍首的溫暖海水還可能會將冰河往後推至不穩定的環境。」

"Totten Glacier is only one outlet for the ice of the East Antarctic Ice Sheet, but it could have a huge impact. The East Antarctic Ice Sheet is by far the largest mass of ice on Earth, so any small changes have a big influence globally."

「雖然托滕冰河不過是東南極冰原往海洋流動的管道之一，但它仍可能會造成重大影響。東南極冰原身為當今地球上最大的冰層，任何一點小小的變動都可能對全世界造成巨大的衝擊。」

To uncover the history of Totten Glacier's movements, the team looked at the sedimentary rocks below the glacier using airborne geophysical surveys. From the geological record, influenced by the erosion by ice above, they were able to understand the history of the glacier stretching back millions of years.

為了瞭解托滕冰河移動的歷史，研究團隊利用空中地球物理探測來探測冰河下方的沉積岩。這些地質紀錄會受上方冰河侵蝕作用影響，藉此他們可以得知冰河數百萬年之前的歷史。

They found that the glacier has retreated more quickly over certain 'unstable' regions in the past. Based on this evidence, the scientists believe that when the glacier hits these regions again we will see the same pattern of rapid retreat.

他們發現過去冰河在經過某些不穩定地區時，冰河消融的速度會變得更快。科學家根據這些證據，認為當冰河未來再次經過這種地帶時，我們同樣會看見冰河進入這種快速倒退的模式。

引用自：Imperial College London. "Scientists predict extensive ice loss from huge Antarctic glacier." ScienceDaily. ScienceDaily, 18 May 2016. .

動物已率先回歸世上最重大核災的遺址—車諾比

原文網址：www.sciencedaily.com/releases/2015/10/151005132553.htm

Chernobyl: At site of world's worst nuclear disaster, the animals have returned

動物已率先回歸世上最重大核災的遺址—車諾比

In 1986, after a fire and explosion at the Chernobyl Nuclear Power Plant released radioactive particles into the air, thousands of people left the area, never to return. Now, researchers reporting in the Cell Press journal Current Biology on October 5 have found that the Chernobyl site looks less like a disaster zone and more like a nature preserve, teeming with elk, roe deer, red deer, wild boar, and wolves.

1986年，在車諾比核電廠起火爆炸，往空氣釋放大量放射性粒子後，數以千計的人們離開了這個地區，再也沒有回來。研究人員8/5於細胞出版社的期刊《當代生物學》(Current Biology)中記述，他們發現車諾比廢墟目前看起來不像是重災區，反而比較像自然保護區，有成群的馬鹿、麆鹿、紅鹿、野豬和野狼生活於此。

The findings are a reminder of the resilience of wildlife. They may also hold important lessons for understanding the potential long-term impact of the more recent Fukushima disaster in Japan.

這項發現提醒了我們野生生物的生命力是如此堅韌。而這對我們欲瞭解最近發生的一次核災—日本福島事件的長期影響來說，也是十分重要的一課。

"It's very likely that wildlife numbers at Chernobyl are much higher than they were before the accident," says Jim Smith of the University of Portsmouth in the UK. "This doesn't mean radiation is good for wildlife, just that the effects of human habitation, including hunting, farming, and forestry, are a lot worse."

「車諾比的野生動物數目很有可能比事故發生之前還高出許多，」英國樸茨茅斯大學的Jim Smith說。「這並不代表放射性有益於野生生物，只是人類居住的影響，包括狩獵、農耕以及伐林造成的影響更為糟糕。」

Earlier studies in the 4,200 km² Chernobyl Exclusion Zone showed major radiation effects and pronounced reductions in wildlife populations. The new evidence, based on long-term census data, now shows that mammal populations have bounced back.

更早對車諾比隔離區4200平方公里進行的研究顯示，大量輻射造成了野生生物族群數目大幅降低。然而，根據長期普查數據而得出的新證據顯示，目前哺乳類族群的數目已經回升。

The relative abundance of elk, roe deer, red deer, and wild boar within the exclusion zone are now similar to those in four uncontaminated nature reserves in the region, the researchers report. The number of wolves living in and around the Chernobyl site is more than seven times greater than can be found in those nature reserves.

研究人員記述，在隔離區內的馬鹿、麆鹿、紅鹿和野豬的數目，已跟位於同一地區中的四座保護區相去不遠。而車諾比場址之內和周圍的野狼數目甚至是那些自然保護區的七倍以上。

Helicopter survey data also reveal rising trends in the abundance of elk, roe deer, and wild boar from 1 to 10 years after the accident. A dip in the wild boar population at one point was traced to a disease outbreak unrelated to radiation exposure.

直升機調查的數據也顯示馬鹿、麆鹿和野豬的數量在事故發生之後1至10年便開始有上升趨勢。野豬數目雖然曾一度下降，但原因可追溯至疾病爆發而非暴露於輻射下。

"These results demonstrate for the first time that, regardless of potential radiation effects on individual animals, the Chernobyl Exclusion Zone supports an abundant mammal community after nearly three decades of chronic radiation exposure," the researchers conclude. They note that these increases came at a time when elk and wild boar populations were declining in other parts of the former Soviet Union.

「這些調查結果首度顯示，不管輻射對單一生物個體的作用如何，車諾比隔離區歷經了30年的長期輻射暴露，仍可以讓相當大量的哺乳類族群生存於此。」研究人員總結說。他們注意到馬鹿和野豬數目開始增加的時間點，卻是牠們在前蘇聯其他地區數目開始減少之時。

"I've been working, studying, and taking photos of the wonderful wildlife in the Chernobyl area for over 20 years and am very pleased our work is reaching an international scientific audience," says Tatiana Deryabina from the Polessye State Radioecological Reserve in Belarus, a few miles from the site of the Chernobyl accident.

「我在車諾比地區工作、進行研究和拍攝這些美好的野生生物已經超過了20年，現在我十分高興我們的工作成果終於能傳達到國際科學社群之中」Tatiana Deryabina說，他工作的地點，白俄羅斯的波利西亞國家輻射生態保育區距車諾比意外場址只有幾公里之遙。

"These unique data showing a wide range of animals thriving within miles of a major nuclear accident illustrate the resilience of wildlife populations when freed from the pressures of human habitation," says Jim Beasley, a study co-author at the University of Georgia.

「這些獨一無二的數據展現出在重大核災區的數公里內，各式各樣的動物仍能繁榮興旺。這說明了當脫離了人類定居造成的壓力後，野生生物有多麼地強韌。」共同作者，喬治亞大學的Jim Beasley說。

引用自：Cell Press. "Chernobyl: At site of world's worst nuclear disaster, the animals have returned." ScienceDaily. ScienceDaily, 5 October 2015. 

在煤灰中發現放射性汙染物

原文網址：www.sciencedaily.com/releases/2015/09/150902111835.htm

Radioactive contaminants found in coal ash

在煤灰中發現放射性汙染物

Landfill, pond storage of coal ash is currently unregulated

然而目前尚未設立煤灰掩埋場和貯留池的相關規範

A new Duke University-led study has revealed the presence of radioactive contaminants in coal ash from all three major U.S. coal-producing basins.

杜克大學進行的新研究顯示來自美國三大產煤盆地的飛灰皆含有放射性汙染物。

The study found that levels of radioactivity in the ash were up to five times higher than in normal soil, and up to 10 times higher than in the parent coal itself because of the way combustion concentrates radioactivity.

研究顯示跟正常土壤相比，灰燼的輻射強度可強上5倍；且因為燃燒後放射性物質會濃縮，強度甚至可高達原本煤炭的10倍之多。

The finding raises concerns about the environmental and human health risks posed by coal ash, which is currently unregulated and is stored in coal-fired power plants' holding ponds and landfills nationwide.

此發現讓人們必須正視煤灰造成的環境污染與人體健康風險。目前煤灰儲存在美國各地燃煤發電廠的貯留池和掩埋場中，但並未制定相關規範。

"Until now, metals and contaminants such as selenium and arsenic have been the major known contaminants of concern in coal ash," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment. "This study raises the possibility we should also be looking for radioactive elements, such as radium isotopes and lead-210, and including them in our monitoring efforts."

「在已知煤灰含有的汙染物質中，目前為止是以金屬和硒、砷這類汙染物為主要監管對象。」杜克大學環境學院，專長為地球化學與水質相關的教授，Avner Vengosh說。「本研究提醒我們應該要去偵測放射性元素，像是鐳同位素和鉛-210可能造成的汙染，並將它們列入監管項目中。」

Rdium isotopes and lead-210 occur naturally in coal as chemical by-products of its uranium and thorium content. Vengosh's research team revealed that when the coal is burned, the radium isotopes become concentrated in the coal ash residues, and the lead-210 becomes chemically volatile and reattaches itself to tiny particles of fly ash. This causes additional enrichment of radioactivity in the fly ash.

作為煤炭本身含有的釷和鈾產生的化學副產物，鐳同位素與鉛-210原本就會在煤炭中出現。Vengosh領導的團隊顯示燃燒煤炭時，鐳同位素會集中在殘留的煤灰中；而鉛-210則會變得具有化學揮發性，並重新吸附在微小的飛灰顆粒上，造成飛灰中有額外的高濃度放射性物質。

"Radioactive radium and lead-210 ends up concentrated in these tiny particles of fly ash, which though individually small, collectively comprise the largest volume of coal ash waste going into holding ponds and landfills," said Nancy Lauer, a Ph.D. student in Vengosh's lab who was lead author of the study.

「放射性鐳和鉛-210最後會集中於這些微小的飛灰顆粒上。雖然單顆顆粒相當細小，但在棄置於貯留池和掩埋場的煤灰廢棄物中，這些顆粒集合起來後卻是體積最大的一部分。」本研究的第一作者Nancy Lauer說，她是Vengosh實驗室的博士生。

Vengosh, Lauer and their colleagues published their peer-reviewed paper Sept. 2 in the journal Environmental Science & Technology.

Vengosh、Lauer和他們的同僚將他們的論文發表在9月2日的同儕審定期刊《環境科學與技術》之中。

The study comes as the U.S. Environmental Protection Agency's first-ever regulations on coal ash disposal are set to go into effect in October.

促成本研究的原因為美國環境保護署將在十月開始實施首次針對煤灰處置的相關規範。

Currently, coal ash disposal sites are not monitored for radioactivity, Vengosh noted, "so we don't know how much of these contaminants are released to the environment, and how they might affect human health in areas where coal ash ponds and landfills are leaking. Our study opens the door for future evaluation of this potential risk."

Vengosh注意到目前煤灰處置場的放射性並未被監控，「因此我們無法得知這些汙染物中到底有多少已經排放到環境裡；以及在煤灰池和掩埋場有所滲漏的地區，它們可能會如何影響人體健康。我們的研究開創了對此潛在風險的評估。」

Smokestack scrubbers installed at U.S. power plants keep these contaminants from escaping into the air when the coal is burned, he stressed. But if the contaminated coal ash is spilled, or if effluents leak from ponds or landfills, it may pose a hazard.

他強調，美國的火力發電廠在燃燒煤炭時，都有配備煙囪刷洗器來避免這些汙染物排放至空氣。然而，若這些受汙染的煤灰從煤灰池或掩埋場滲出或溢出，就有可能造成危害。

"Because of the tiny size of the fly ash particles, they are much more likely to be suspended in air if they are disposed in a dry form. People breathing this air may face increased risks, particularly since tiny particles tend to be more enriched in radioactivity," Lauer said.

「若在乾燥狀態下處置這些飛灰，由於它們的顆粒十分細緻，使得它們很有可能會懸浮在空氣當中。人類若呼吸到含有這些微粒的空氣，受到的健康風險便會增加，尤其是這些微粒可能有較高的放射性。」Lauer說。

Vengosh said this study is the first systematic study to compare radioactivity in coal and coal ash from the Illinois, Appalachian and Powder River basins. The researchers collected multiple samples of coal and coal ash from all three coal-producing basins and then measured the radioactive elements in each sample.

Vengosh說這篇研究首度系統性地比較了伊利諾州、阿帕拉契州和保德河盆地的煤炭與煤灰中的放射性。研究人員分別從這三個產煤盆地中採集許多煤炭與煤灰的樣品，接著測量每個樣品中的放射性元素濃度。

Their tests showed that coal and coal ash from different basins exhibited different levels of radioactivity -- the Illinois basin had the most, followed by the Appalachian and then the Powder River, which is in Wyoming and Montana. The tests also showed that the ratio of radium to uranium in the parent coal was consistent with the ratio found in its residual coal ash.

測試結果顯示產自不同盆地中的煤炭和煤灰，會具有不同強度的放射性。三者中以伊利諾州最高，阿帕拉契州次之，最低則是位處懷俄明州和蒙大拿州的保德河盆地。測試結果也呈現出原本的煤炭以及殘餘煤灰中，鐳與鈾的比例會兩者相等。

"This means we can predict how much potential radioactivity will occur in coal ash by measuring the uranium content in the parent coal, which is easily discerned," Vengosh said. "This analysis can be applied to all coal ash worldwide, and is useful information for regulators, industries and scientists alike."

「這意味著藉由測量原本煤炭的鈾含量，我們可以預估煤灰的放射性可能會有多強，而煤炭的鈾含量是相當容易測量的。」Vengosh說。「此分析結果可以適用在全世界的煤灰，並且能提供相關產業的管理者、業界和科學家相當有用的資訊。」

Because the isotopic ratios of the coal and coal ash varied between basins but were consistent within each individual basin, researchers can also use them to determine the source of environmental contamination. "They allow us to not only distinguish between the three basins, but also to determine whether contaminants are coming from coal ash or some other naturally occurring source in the local environment," Lauer said.

雖然不同盆地中的煤炭和煤灰的同位素比例不同，但來自同一盆地的卻會一樣，因此研究人員可以利用同位素比例確認環境汙染的來源。「同位素比例不只能讓我們區分出煤灰來自三個盆地中的哪一個，也可以用來辨別汙染物究竟是來自煤灰或是當地自然產生的其他物質。」Lauer說。

引用自：Duke University. "Radioactive contaminants found in coal ash: Landfill, pond storage of coal ash is currently unregulated." ScienceDaily. ScienceDaily, 2 September 2015.