pbs高端访谈:污染物随降雨进入水体致有毒鸡尾酒

 　　JEFFREY BROWN:For those stations not taking a pledge break, we go beneath Washington’s Puget Sound to look at stormwater runoff.

　　Our story comes from our colleagues at KCTS9 in Seattle. Katie Campbell reports for Earth Fix, a public media project focused on environment reporting in the northwest.
　　KATIE CAMPBELL:Laura James has been diving in Puget Sound for more that 20 years.
　　LAURA JAMES, DIVER: Just the feeling of being weightless, it’s just like flying. The animals are fantastic and so different than anything you’ll ever see up here on the surface. It’s kind of like going into wonderland.
　　I don’t think that people realize what a gem 1 we have. It’s the Emerald Sea. It’s got so much life. The cold water has more nutrients 2; it can hold more oxygen, hold more nutrients than warm water, so you get tremendous invertebrate 3 marine 4 life. You get octopus 5 and wolf eels 6 and all sorts of sea slugs, just every color of the rainbow.
　　You go beneath the sea, and it’s you’re in this different world, and it’s mesmerizing 7 and brilliant.
　　KATIE CAMPBELL: One day, she came across something in the water that has haunted her ever since.
　　LAURA JAMES:We were coming up the slope, and I saw what looked like a piling. It was this big black column, and as we got closer I realized that it was actually a storm outfall. And it was so full of road grime and who knows what that it was just black. And it was just billowing and billowing and it was, it just doesn’t stop.
　　I of course went home and I started looking it up on the Internet. I’m like "what’s in stormwater?" And I’m like, "we don’t want that there."KATIE CAMPBELL:Stormwater is a toxic 8 cocktail 9 of sediment 10, grease, tire wear, and any litter small enough to slip into storm drains. And that’s just what you can see. There’s much more we can’t see.
　　Microscopic 11 particles of heavy metals like copper 12 and zinc 13 are commonly found in urban highway runoff. There’s also oil and petroleum-based hydrocarbons 14. Contrary to what a lot of people think, runoff is Puget Sound’s biggest source of pollution.
　　GILES PETTIFOR, King County Stormwater Permit Team: Approximately 50 percent of the region believe that stormwater is treated, is captured and then conveyed for treatment to a treatment plan of some type. When in fact this doesn’t take place, and almost all of this water goes off totally untreated.
　　KATIE CAMPBELL:Throughout the United States, so much land has been paved over that the total amount of impervious 15 surfaces would cover an area the size of Ohio. Every time water washed over these hard surfaces, pollutants 16 pour into the nearest waterway.
　　JENNIFER MCINTYRE, Washington State University: All these impervious surfaces means that water can’t get through them, whereas if it rains in the forest, the water hits the ground and then very slowly seeps 17 into the soil, and the soil acts like a sponge. It slows down the water, it cleans the water out, it filters it. And obviously an impervious surface like pavement just doesn’t do that at all.
　　KATIE CAMPBELL: Jennifer McIntyre is leading a team that’s studying how polluted runoff impacts aquatic 18 animals. The team recently collected runoff form a highway in Seattle and trucked it down to the Washington Stormwater Center.
　　It’s one of the only facilities in the world that’s conducting cutting edge research on what’s known as green stormwater infrastructure 19.
　　GILES PETTIFOR:Green stormwater infrastructure is building stormwater control structures that more closely mimic 20 natural settings – things like rain gardens, bio-soils, green roofs, these are developing facilities or things that help improve water quality that are trying to mimic those natural filtration, you know, aspects of water infiltrating 21 into the ground, or flowing through vegetation.
　　KATIE CAMPBELL:Around the northwest and across the country, new rules are being written that would require cities and counties to adopt green stormwater methods. But this prospect 22 is causing some concern. Because green stormwater methods, such as rain gardens, are relatively 23 new, little is known about them, or even whether they’d make any difference.
　　JENNIFER MCINTYRE:People are running out there and just building rain gardens, and that’s great, but there’s the potential for them not to work because we don’t know very much about them yet. So some of the things we’re hoping to learn here at this facility are: what are the best soil mixtures to use, what are the best plants to use, how long will these systems hold up to a continuous input 24 of contaminants coming from stormwater runoff.
　　We know that they reduce some of the contaminants in stormwater. We know that the flows can be reduced. These are all really good things. But is that enough? Is that enough to protect wild fish and their food web from some of the harmful effects of stormwater runoff.
　　KATIE CAMPBELL:That’s what MacIntyre is trying to find out.
　　Once all the stormwater was mixed and samples were taken, the team filtered half the water through soil columns that mimic what happens in a rain garden. They then filled this series of aquariums 26 – half with the straight highway runoff and half with runoff that had gone through rain garden filtration.
　　JENNIFER MCINTYRE:And each aquarium 25 got 10 juvenile 27 Coho salmon 28 and then pretty much we waited to see what would happen.
　　KATIE CAMPBELL:Her plan was to monitor the salmon for four days, but within 12 hours all the fish that were in the straight highway runoff were dead. And the fish in the filtered runoff? All still alive.
　　JENNIFER MCINTYRE:I think it’s really telling that we can take something as concentrated and toxic as highway runoff and pass it through soil columns and have it no longer be acutely lethal 29 to fish.
　　KATIE CAMPBELL:While Jennifer McIntyre searches for answers in the lab, Laura James is trying to raise awareness 30 in the real world by documenting the effects of stormwater with her camera.
　　LAURA JAMES:If I can capture this on film, if I can share this, it will truly give our waters a voice. Because people see it, and they’re they’re just – it’s like shock. They stop what they’re doing and they actually look. It’s like a connection.
　　I see Puget Sound and our oceans as a reflection of us. They’re a reflection of our humanity and these stormdrains are like a conduit of our humanity running in there.
　　JUDY WOODRUFF:The Environmental Protection Agency at the federal level is in the process of strengthening national storm water regulations.