PBS高端访谈:如何解决洪水后的水污染问题（在线收听）

JUDY WOODRUFF: As hurricanes become more intense and wetter due to climate change, massive flooding events from hurricanes like Florence and Harvey may become even more severe and occur more frequently. Yet surprisingly little is known about the contaminants lurking in storm waters afterward and their impacts on human health. Special correspondent Cat Wise reports now from North Carolina, where there's an effort under way to change that. It's part of our weekly look at the Leading Edge of science, technology and health.

CAT WISE: Eight trillion gallons, that's the estimated amount of rain that fell across North Carolina from Hurricane Florence. During the catastrophic flooding that followed, hog lagoon waste, raw sewage, and coal ash were among the toxic substances that flowed into waterways and communities. University of North Carolina scientist Rachel Noble spent a lot of time in those floodwaters. She collects samples after extreme storms, more than 1,000 since Florence, and brings them back to her lab. Noble and her students are studying the pathogens in floodwaters, drinking water, and shellfish. Two months after the storm, they continue to see problems.

RACHEL NOBLE, University of North Carolina: It's gone on longer than we might have expected, and we're also seeing contamination that is popping up in locations that we might not have expected it.

CAT WISE: Contact with floodwaters can cause skin infections and diarrheal illnesses, but in rare instances, exposure can be deadly. Wounds infected with certain strains of vibrio, a bacteria which likes warm brackish waters, an kill within 24 hours if not treated.

DR. VICKI MORRIS, Carteret Health Care: The main thing that I think we have noticed is an increase in the number of salmonella cases.

CAT WISE: Vicki Morris is a local infectious disease doctor who has seen an uptick in flood-associated illnesses. She says it's often hard to know to what her patients have been exposed to.

DR. VICKI MORRIS: Right now, if a patient comes in, we have to do a culture, and it can take 48 to 72 hours for the germs to grow. If I knew what were in the floodwater or the drinking water of my patients, it would help me choose the initial antibiotics with more info to go on.

CAT WISE: Noble agrees there is a big need for more water quality testing during floods and faster results.

RACHEL NOBLE: The way the system works is that we often tell people about the results of contaminated water after they have already had them to drink or after they have already been exposed to them. We're telling them in the newspaper and on the Internet after the fact.

CAT WISE: Part of that lag time, she says, is due to water testing agencies often being overwhelmed and out of power during flooding events. But it's also because current tests, which look for signs of E. coli, a telltale bacteria for other pathogens, are slow. She's developed a way to speed things up.

RACHEL NOBLE: This is the existing test that we use for bacteria in water. It relies on growing the bacteria from the water, and it will take about 24 hours for a result. The new test we have developed actually determines the amount of DNA of a certain type of bacteria, so, in this case, E. coli, and we can get a result from this test in about an hour.

CAT WISE: Noble's new test, which is undergoing regulatory review by the EPA, is currently processed in her lab using a DNA sensing machine. But in the future, she hopes to be able to go mobile. While progress is being made on rapid water tests, another challenge for researchers after big storms is tracking where contaminated waters are flowing. But a unique collaboration is now under way to tackle that problem with some sophisticated new tools. On a recent morning, Duke University scientists Dave Johnston and Rett Newton joined Noble for a scenic boat ride with an important scientific goal: to test two devices they hope will one day transform the way floodwaters and sources of contamination are tracked.

DAVE JOHNSTON, Duke University: Once we have the autonomous boat on station, then we can get the drone ready to go.

CAT WISE: Johnston and Newton are in the early stages of using autonomous boats and drones with highly sensitive cameras to survey and sample waters difficult for researchers like noble to reach. Back on shore at Duke's Marine lab, which was hit hard by Hurricane Florence, Johnston explained why the new tools are helpful.

DAVE JOHNSTON: There are a lot of places where you don't want people to actually expose themselves to those places. Think about doing water quality testing at a mine tailing pond, right? So programming a little boat to travel up into a tidal creek, or to have program a drone to go over to a certain spot and take a sample, those are revolutionary technologies that allow us to sample in places that people just can't get to.

CAT WISE: The team is also outfitting drones with thermal cameras, which can provide a clear picture of where sources of water are flowing, a tool that could be helpful when trying to pinpoint sources of contamination.

DAVE JOHNSTON: In this case, we see water that's coming from a warm area, and we're able to actually see where that water is going. It's pretty cool. It takes a pretty sharp left-hand. We'd be able to say, hey, there's a potential for exposure in these locations.

CAT WISE: Rett Newton is a Ph.D. student at Duke who knows his way around high-tech equipment. He also happens to be a retired Air Force colonel who flew F-15s, and he's the current mayor of Beaufort, a picturesque coastal town which experienced flooding after Florence. When he's not tending to the needs of his community, he is often out flying drones over the local waterways. Is this an exciting time to be in this field?

RETT NEWTON, Duke University Ph.D. Student: It's really exciting, yes, even for a crusty old guy like me watching the young folks, the young students, and they're really fired up. Every single day, we're seeing new platforms, new sensors, new applications. And a lot of the power is in the processing right now, trying to get the processing quicker for us to get some of this data in near real time.

CAT WISE: UNC's Rachel Noble is hoping all that new data and other rapid water tests she's developing, including one for vibrio, will help to keep the public better informed during future storms. For the PBS NewsHour, I'm Cat Wise in Morehead City, North Carolina.

朱迪·伍德拉夫：如今，气候变化导致飓风火力更猛、湿度更大，佛罗伦萨、哈维等飓风引发的大型洪灾可能也会随之愈发严重和频繁。不过，让人意外的，公众对风暴带来的污染物以及污染物对人类健康的影响却知之甚少。下面请听我台特派记者卡特·怀斯从北卡罗来纳州发回的报道，该州正在努力扭转这种局势。借此机会，我们也顺便了解下本周科学技术与健康领域的最新消息。

卡特·怀斯：8万亿加仑——这是佛罗伦萨飓风给北卡罗来纳州带来的预计降雨量。飓风过后就是灾难性的洪灾，洪灾会带来泻湖污物、未经处理的污水、煤灰等剧毒物质，这些物质都会流入水道中，影响各社群。北卡罗来纳大学科学家雷切尔·诺贝尔花费了大量时间研究洪灾。她手收集了特大暴雨后的洪水样本，自佛罗伦萨飓风发生后，她收集了1000多份样本，并将样本带回了自己的实验室。诺贝尔及其学生正在研究洪水、饮用水和甲壳类动物中的病原体。佛罗伦萨走后2个月，他们依然发现病原体问题严重。

雷切尔·诺贝尔，北卡罗来纳大学：这种情况持续的时间比我们预想得要长。此外，我们还发现污染问题出现在了我们未曾预想过的一些地方。

卡特·怀斯：如果跟洪水发生接触，就会导致皮肤感染和疟疾。而且在极少数的情况下，可能会致死。伤口若是感染了弧菌菌株，并在24小时未能接受治疗，就会死亡。弧菌这种菌类喜欢在温暖咸的水里生活。

薇琪·莫里斯博士，卡特里特卫生保健中心：我认为我们注意到的主要问题是——感染沙门氏菌的病例增加了。

卡特·怀斯：薇琪·莫里斯是当地主治感染类疾病的医生。她发现，洪灾引发的病例有上升趋势。她表示，通常很难判定自己的病人究竟是因为接触了什么才致病的。

薇琪·莫里斯：现在，每当有人来看病，我们就会做菌株培养，而菌株需要48-72小时才能培养成。如果我能知道洪水或病人所饮用的水里有什么，这样的信息就有助于我确定一开始用什么抗生素。

卡特·怀斯：诺贝尔认为，急需在洪灾期间对水质进行更多的检测，出结果的速度也要加快。

雷切尔·诺贝尔：我们体系运作的方式是：我们告诉病人水质污染的检测结果时，他们一般已经饮用了污水，或者已经接触过不干净的水源。无论是通过纸媒还是网络，我们告知大家的时候总是在已经出现问题之后。

卡特·怀斯：她表示，出现这种时间差的部分原因是——水质检测机构在洪灾发生后，不是被淹没了，就是断电了。还有部分原因是：当前针对大肠杆菌（可以表征其他病原体是否存在）的检测速度很慢。她已经找到方法来给检测进行加速了。

雷切尔·诺贝尔：这项测试其实已经有了，是我们用来测试水中细菌的。该测试靠的是培养水中的细菌，大概24小时就可以出检测结果。我们研制的这项新测试可以确定某种细菌的DNA含量。以现在这个为例，就是大肠杆菌的DNA含量。然后大概用一个小时就可以得到检测结果。

卡特·怀斯：诺贝尔的这项新测试正在环境保护局进行监管审核，同时也在她的实验室用DNA传感器进行处理。以后，她希望这种方法可以更有机动性。虽然在水质检测方面的速度加快了，但暴雨后研究人员还面临一项挑战——跟踪污水流向。目前，有人在进行史无前例的合作，以解决这个问题。他们用到的是复杂的新工具。最近的一个早上，杜克大学科学家戴夫·约翰斯顿和雷特·牛顿跟诺贝尔一起游湖。他们有一个重要的科学目标：检测两个装置，以期未来能改变人类追踪洪水和污水走向的方式。

戴夫·约翰斯顿，杜克大学：什么时候站里有了自动船，什么时候无人机就能投入使用了。

卡特·怀斯：约翰斯顿和牛顿还在自动船和无人机研发的初期，虽然有灵敏度极高的相机来辅助调研，但其所面临的水质样本对诺贝尔这样的科学家来说很难研究。杜克大学也遭遇了佛伦伦萨的重创，而在其海洋实验室里，约翰斯顿解释了这种新工具的价值所在。

戴夫·约翰斯顿：有很多地方是我们不希望人们去的。试想一下在矿山的尾矿池里做水质检测的场景，你就知道了。所以，给小船编程，让其能自动进入潮沟；给无人机编程，让其能去往指定地点提取样本。这些都是技术变革，让我们可以去人类不能去的地方提取样本。

卡特·怀斯：该小组还在无人机上装了热感摄像机，可以清晰展示水源的流向。这个工具很有用，可以帮助我们确定污染源的位置。

戴夫·约翰斯顿：在这个应用案例里，我们可以看到水源来自于一个温暖的区域，也能看到水流的走向。这个工具很好，带着锋利的左手。我们终于能说，暴置于这样的环境里也是有可能的。

卡特·怀斯：雷特·牛顿是杜克大学的博士后，对高科技设备有自己的见解。恰好他此前是空军上校，曾驾驶过F-15，现在已退役。他现在是博福特市长。博福特是一个海滨小镇，在佛罗伦萨飓风后就遭遇了洪灾。他平时不是在为社群的需求而操心，就是出去开无人机，飞翔在当地水道上空。难道不兴奋吗？

雷特·牛顿，杜克大学博士后：很兴奋，确实如此，即便是像我这种老古董看着年轻人和学生的时候，总是能感觉到他们的热血。每天，我们都观测新的平台、新的传感器和新应用。很多力量都在酝酿中，努力让进程更快，让我们以接近实时的速度获取数据。

卡特·怀斯：北卡罗来纳大学的雷切尔·诺贝尔希望，所有新数据以及她研究的快速水质检测方法，比如弧菌检测的方法，都能帮助公众更好地了解未来的风暴。以上是卡特·怀斯从北卡罗来纳州莫赫德港发回的《新闻一小时》报道。