Air Date: September 19, 1997

SEGMENTS

Pfiesteria: Cell from Hell / Diane Toomey

An unusual single celled organism that seems to flourish in polluted waters is being blamed for massive fish kills in Maryland, Delaware, Virginia and North Carolina. The disease agent is called Pfiesteria, and scientiests have dubbed it the cell from hell. Now, some researchers, anglers and divers suspect it may also harm humans. The pfiesteria outbreak has become so widespread that no less than four various government bodies are looking into its causes and ways to control it. Reporter Diane Toomey begins her story near the site of one of the earliest reported Pfiesteria outbreaks, on North Carolina's Neuse River. (11:50)

Andrea's Tern / Andrea DeLeon

Trying to bring species back from the brink of extinction is often a delicate, if not impossible task that requires much attention to detail. Even one unanticipated problem can spell disaster. That's what Andrea DeLeon, who works for Maine Public Broadcasting, discovered while covering efforts to protect the Least Tern along Maine's coast. She shares her thoughts with us in this reporter's notebook. (02:42)

Garden Spot: Seed Saving

Steve Curwood met with Living On Earth gardening expert Michael Weishan at Michael's garden to discuss the importance and the joys of growing old time varieties of today's vegetables. (05:30)

The Living on Earth Almanac

Facts about... discoveries by the Lewis and Clark Expedition. (01:15)

Dental Bonding: Dangerous to your Health?

In recent years, the American Dental Association (ADA) has been advocating the use of plastic dental sealants to fill cavities. However, in a study whose findings were published in the journal Environmental Health Perspectives, some of the plastics used appear to contain some possibly health damaging ingredients. Now the ADA is modifying it's position to endorse the use of those sealants only which do not contain the potentially harmful synthetic chemicals. (07:33)

Salmon Farming: The Down Side / Bob Carty

With the numbers of wild fish plummeting around the world, fish farming is often touted as a good way to satisfy demand. It's already big business. Now just about half of the salmon sold in this country is raised in pens set out in coastal waters. But some say as aquaculture has grown, too many fish farms operate in ways that hurt the environment and pose health threats to humans. As Bob Carty found out, no where are concerns more pointed than in British Columbia, the world's fourth largest producer of farmed salmon. (13:35)

Fire Down Below / Constantine von Hoffman

Hollywood loves a guns and guts movie, and the recent box office success of the new Steven Seagal flick, Fire Down Below, shows the formula can even be applied to environmental themes . Living on Earth's private eye at the movies, Constantine von Hoffman has a review. (03:30)

Show Credits and Funders

Show Transcript

HOST: Steve Curwood
REPORTERS: Diane Toomey, Andrea DeLeon, Brenda Tremblay, Bob Carty
GUEST: Michael Weishan
COMMENTATOR: Constantine von Hoffman

(Theme music intro)

CURWOOD: From National Public Radio, this is Living on Earth.

(Music up and under)

CURWOOD: I'm Steve Curwood.

A tiny one-celled creature is killing millions of fish and threatening the health of humans as well. It's called pfisteria, and it thrives in polluted water.

BURKHOLDER: We poured millions and millions of tons of fertilizers, human sewage, swine waste, poultry waste, all kinds of different forms of nitrogen and phosphorus and other organic wastes that pfisteria likes into these estuaries for the past 50 to 70 years, and I think slowly over time we slowly shifted the balance more in favor of this organism to become toxic.

CURWOOD: Also, if you garden, why you should give heirloom plants a try.

WEISHAN: It is extremely important to capture this genetic material and preserve it. I mean, the eating benefits are sort of a sideline.

CURWOOD: We'll have those stories and more this week on Living on Earth. But first, news.

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(break for news)

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Pfiesteria: Cell from Hell

CURWOOD: This is Living on Earth. I'm Steve Curwood.
An unusual single-celled organism that seems to flourish in polluted waters is being blamed for massive fish kills in Maryland, Delaware, Virginia, and North Carolina. The disease agent is called pfisteria and scientists have dubbed it the cell from Hell. And now, some researchers, anglers, and divers suspect it may also harm humans. The pfisteria outbreak has become so widespread that no less than 4 various government bodies are looking into its causes and ways to control it. Reporter Diane Toomey begins her story near the site of one of the earliest reported pfisteria outbreaks, on North Carolina's Neuse River.

TOOMEY: There was a time when Margaret Jones saw the Neuse River as a giver of life. For years her husband David fished the lower reaches of the river, and ran a small neighborhood seafood market on North Carolina's eastern shore. But the store's been closed for 2 years. Margaret Jones reads the sign that hangs outside it.

JONES: It says, "We told the truth. Therefore, we were put out of business. I'm disappointed and sad. Thanks, Dave."

TOOMEY: In the autumn of 1995, pfisteria hit the lower Neuse. It marked 15 million fish with open, bleeding sores, and killed them. So Mr. Jones wondered if the fish he was selling were safe to eat. No one could give him a straight answer, so he put up a sign that read, "Eat at your own risk." His business soon failed. Now Mrs. Jones believes the same thing that killed the fish infected her husband. He hasn't been able to hold down a job and has trouble holding conversations. Sitting at the water's edge, she says her husband suffers from a number of symptoms.

JONES: You could still see where he had the sores on his body. His neurological system is really bad. He still has a lot of memory loss. His weight is real bad; he's lost a lot of weight. He can't handle situations. He doesn't like to be around people. It makes him terribly nervous.

TOOMEY: It's not clear what sickened Mr. Jones. There is no lab test that can show if pfisteria has invaded his body. But a neurologist has ruled out other possibilities like Alzheimer's and Muscular Dystrophy. Other fishermen and divers who work for the state say they, too, have been sickened by the water. They complain of skin lesions, shortness of breath, and memory loss. Whether pfisteria is responsible for these illnesses is a controversial question. North Carolina officials have warned people to avoid the water and fish where kill is taking place, but discount the possibility that people who swim or boat on the water could be poisoned by the organism. Dr. Stanley Music is North Carolina's top environmental epidemiologist.

MUSIC: We had some physicians who were asking questions, and we followed through with those, and we found alternative explanations. We had people who complained. We conducted meetings in coastal counties. There were public announcements and requests for people to report. All of these things were followed up on, and nothing came of it.

TOOMEY: But that wasn't the case in Maryland. After a recent fish kill on the Pokomoke River, Maryland quickly assembled a team of doctors to examine more than a dozen sick people there. They concluded pfisteria is the most likely cause of the troubles, which for some patients included impaired brain function. As a result, 2 Congressional hearings, a conference of 5 governors, and a workshop at the Centers for Disease Control have all been scheduled on pfisteria. Just days after Maryland physicians announced their findings, North Carolina's health department decided to set up its own team of doctors to evaluate possible pfisteria cases. Cases that critics say have been under North Carolina's nose for years. Dr. Music says the Maryland study is impressive, but he says much more research is needed.

MUSIC: It's just in this one place, in Pokomoke City, where for reasons that we do not understand there is an apparent cluster of cases. But even that needs much further definition before we are satisfied that we understand what it all means.

TOOMEY: That more exact definition may soon be on the horizon in the form of a diagnostic test.

BURKHOLDER: We have been able to isolate and purify biologically active, physiologically unique, water-soluble neurotoxin from pfisteria.

TOOMEY: Joanne Burkholder is an aquatic botanist at North Carolina State University. She identified the unusual organism in the lab in 1988, and at the site of a fish kill a few years later. But pfisteria has been an elusive quarry. Part animal, part plant, a shape-shifter with 100 forms and 24 life stages to call upon. Unlike any other of its kind, it hunts, shooting out a poison that never fails to kill its target.

(Voices milling)

TOOMEY: Speaking at an August conference of marine scientists, Dr. Burkholder said corralling the toxin was a real breakthrough.

BURKHOLDER: That is going to really open the door to help us to understand a lot more about how and where people are being affected. What tissues the toxin would go into, how it actually works inside of a person to cause some of the symptoms we have sustained.

TOOMEY: Dr. Burkholder says 4 years ago she and a number of colleagues were poisoned by pfisteria fumes in her lab. They suffered from nausea, mood swings, and memory loss, with some symptoms persisting to this day.

(Buzzing; boat motor)

TOOMEY: So where are we headed, Rick?

DOVE: We're heading down the river toward the mouth of the river. We're going to one of the hottest areas for fish kills in the Neuse river, which happens to be about right in front of my house.

(Music up and under)

TOOMEY: Rick Dove likes to say his job is to give a voice to this waterway. He is the river keeper, hired by the Neuse River Foundation to monitor conditions here. Mr. Dove is at east on the water, but his straight back hints at his former career as a Marine Corps colonel. These days his business card pictures a dead fish.

DOVE: In this whole area here, we would go from one side of the river to the other and all you would do was just count dead fish floating everywhere.

TOOMEY: That was in the pfisteria outbreak a couple of years ago that killed 15 million menhaden. In 1991 one billion fish died. This year in North Carolina, pfisteria has killed about a million fish in the Neuse and Pamlico estuaries. And the height of the fish kill season is still ahead.

(Chains being drawn on wood?)

TOOMEY: Rick Dove stands on his dock and throws a cast net into the water.

(Splashing sounds)

DOVE: Let's see what we've got, if there's any sores on them. Now look at this one right here, it's exactly what I'm talking about. See this size, this is about half the size of a dime. It's going to get much bigger, but you see how it's a round open ulcerated bleeding sore, the red, you can see the flesh and everything. Pfisteria has done that to this fish. This fish will not live.

TOOMEY: Pfisteria belongs to the order of life called dinoflagellates. Some of these take the form of algae and some cause the toxic blooms known as red tides. Pfisteria has been found in waters from Delaware to the Gulf of Mexico. And for much of the year it lies dormant as a cyst in the river's sediment. Then by a mechanism not clearly understood, the cell transforms into a toxic state, including one that looks under a microscope like the scrunched up face of an angry baby. At this point the microbe has grown a tail to propel itself and a suction cup appendage called a pedunkle to attach and feed on its prey.

BURKHOLDER: Here's live pfisteria. It's kind of dancing about, it's been consuming human blood cells.

TOOMEY: Dr. Burkholder peers into a microscope at a pfisteria cell in one of its many guises. It takes intense training to be able to identify all the stages of the organism. Burkholder is one of the few people who can do it, so she's compiling an album of mug shots to help other scientists identify pfisteria. She says the organism naturally thrives in brackish estuaries where fresh and ocean waters mingle. But pfisteria may have other preferences as well.

BURKHOLDER: About 75% of our fish kills have occurred, that we've implicated pfisteria in at least, have occurred in degraded waters, where there is nutrient over-enrichment. Both nitrogen and phosphorus tend to be involved.

TOOMEY: In other words, in rivers like the Neuse, which are overfed. There, excess nitrogen has spurred algae growth, which in turn has robbed the river of oxygen.

BURKHOLDER: We poured millions and millions of tons of fertilizers, human sewage, swine waste, poultry waste, all kinds of different forms of nitrogen and phosphorus and other organic wastes that pfisteria likes into these estuaries for the past 50 to 70 years, and I think slowly over time we slowly shifted the balance more in favor of this organism to become toxic.

TOOMEY: Embarrassed by enormous fish kills and hog waste spills, North Carolina has taken some anti-pollution actions. The state legislature has just passed a 2-year moratorium on new hog farms and for the first time set nitrogen discharge limits for municipal sewage treatment plants. The state has also set up a rapid response team to investigate fish kills and perform regular water testing on the Neuse. Preston Howard is the director of North Carolina's Water Quality Division.

HOWARD: North Carolina's water quality environment has been on the front page a lot lately, and having environmental issues on the front page brings a lot of pressures on the agency to respond.

TOOMEY: But earlier this year North Carolina released a preliminary report that said there are no human health effects and no connection between pfisteria outbreaks and nitrogen pollution. The timing of the release raised some eyebrows, coming as it did right before tourist season and before the science was peer-reviewed. But now the state seems to be open to the idea that pfisteria may be pollution-related. Again, Water Quality Director Preston Howard.

HOWARD: Dr. Joanne Burkholder has done considerable research on pfisteria, and has indicated that there is a connection between nutrient enrichment and pfisteria. And it makes some sense, where you have a nutrient source that you're going to get additional growth and pfisteria's just one of those things that apparently likes nutrients.

TOOMEY: Dr. Burkholder and others say the relationship between pfisteria and pollution is a complex one. It changes depending on what life stage the organism is in. For one thing, nitrogen pollution encourages the growth of algae, another food source for pfisteria.

(Boat motor)

DOVE: It's like diamonds all over the river, all those sparkling lights.

TOOMEY: As scientists continue to try to grasp pfisteria's strange lifestyle, and as the state struggles with regulations, the Neuse River Foundation is taking its fight for a cleaner river to the Federal Government. It's suing for enforcement of the Clean Water Act. Meanwhile, Rick Dove says there's still a lot of life here, despite the degradation. And when he's not chasing down fish kills, the river keeper tries to just enjoy the river he protects.

(Boat motor)

DOVE: Some of the prettiest sunsets you could ever find in North Carolina are right here on the Neuse at this part of it.

TOOMEY: For Living on Earth, I'm Diane Toomey.

(Boat motor)

DOVE: Knock your socks off.

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(Boat motor, fade to music up and under)

Andrea's Tern

CURWOOD: Trying to bring species back from the brink of extinction is often a delicate if not impossible task that requires much attention to detail. Even one unanticipated problem can spell disaster. That's what Andrea DeLeon, who works for Maine Public Broadcasting, discovered while covering efforts to protect the least tern along Maine's coast. We asked her to share her thoughts with this reporter's notebook.

(Surf)

DE LEON: Higgins Beach in Scarborough, Maine, attracts swimmers and sunbathers, surfers, saltwater anglers, and, beside the tidal river that marks the beach's northern edge, a colony of tiny least terns that come to the popular beach to nest on the edge of the dune grass. Biologists believed the endangered birds had made the right choice when they chose to nest at Higgins because the river and a neighborhood of beachfront homes keeps wild predators off the sand.

(Terns shrieking)

DE LEON: But on this day, adult birds reeled wildly over the nesting area, shrieking with alarm and occasionally diving at the 2 biologists who ventured into the colony to catalogue an avian disaster. The sand was littered with bits of speckled egg shell, tern nests were trampled, a newly-hatched chick lay flattened. The apparent culprits: teenagers throwing a beer party.

Perhaps the teens got angry when they found their favorite drinking spot roped off. Perhaps they never read the official-looking signs warning people away from the nesting site of this small endangered shore bird. Perhaps they didn't care. And very likely, they didn't see the birds at all. Nature provided the least tern with several clever means of eluding their natural predators. Their eggs are tiny and resemble the stones tumbled by the surf at Higgins Beach. Tern nests are almost invisible, shallow depressions in the sand with no grass or other material to catch the eye. And the juvenile birds naturally hunker down when they sense danger. They don't run. So it's likely those teenagers walking in the dark never saw the eggs so critical to the species' survival in Maine.

A reward for the capture of the people who trampled the colony remains unclaimed. If residents were shocked at the fate of the birds, by now they've moved on to other, fresher catastrophes. Least terns are, after all, aptly named. Tiny, indistinct to many, un-cuddly, of no measurable value to us humans. They might hardly be missed if they vanished altogether. But, as one biologist put it, no creature should disappear simply for getting in the way of the human desire to drink beer on a beautiful summer night. For Living on Earth, I'm Andrea DeLeon.

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CURWOOD: If you grow vegetables, find out how valuable some of the old heirloom varieties can be in just a moment, right here on Living on Earth.

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(Crows call)

Garden Spot: Seed Saving

CURWOOD: This is Living on Earth. I'm Steve Curwood.
I'm talking to you now from the garden of Michael Weishan. He's Living on Earth's gardening expert, as well as the editor of Traditional Gardening. And right now he's trying to convince me that this bumpy red blob in front of me is a tomato. Michael, come on. (Laughs)

WEISHAN: I know, it doesn't look much like a tomato. But it's a Brandywine tomato, which is an old Amish variety, and it's probably some of the best eating you've ever had in terms of tomatoes.

CURWOOD: So this is what people mean by an heirloom plant.

WEISHAN: This is. Generally, when we talk about heirloom plants, we are talking about vegetables, although it could be flowers and trees as well. But generally vegetables that are more than 50 years old and that have some sort of history or story behind them.

CURWOOD: Aside from the history, why would you want to grow an heirloom plant? I mean, this thing looks terrible.

WEISHAN: Well, the taste is absolutely spectacular. The reason this is not in your stores is not for its appearance. It's for the fact -- see, feel how soft it is? It's actually, it's very soft and very easily bruised, unlike most modern tomatoes.

CURWOOD: Hmmm.

WEISHAN: It's loaded with sugar and juices, and if you would try to ship it, it would fall apart. Now, they don't all look like this. If we just move over here, for instance, here's the yellow variety. And that looks more like (expels breath as he reaches over and picks it) a standard tomato does. Fairly large, round. This is probably a 2-pound fruit,
actually.

CURWOOD: Yeah, this is like a small pumpkin. (Laughs)

WEISHAN: Yeah, it does actually look like a small pumpkin.

CURWOOD: Ooh, even though it's yellow it feels very soft and ripe, like you can eat it now.

WEISHAN: Yeah, exactly. Yeah, absolutely.

CURWOOD: And this grove, really, almost of tomato plants, these are all heirloom plants?

WEISHAN: Well, yes, actually. There's a large number of these Brandywine tomatoes, which happen to be my particular favorite. We have an Italian heirloom called Costa Luco Genovese, which is a wonderful paste tomato. We have a wonderful cherry tomato called Chadwick's Cherry, which is absolutely one of the best eating cherry tomatoes I've ever tasted.

CURWOOD: Where are they? I want to try one right now.

WEISHAN: Yeah, they're way down there at the end here.

(Footfalls on gravel)

WEISHAN: Here's the cherry stand way down here at the end. After wading through the veritable tomato jungle.

CURWOOD: I have to confess I have a weakness for good cherry tomatoes.

WEISHAN: Try one of those.

(Juicy sounds)

CURWOOD: Oh! Wow! It's really sweet, but not in a cloying kind of way. It just boom, explodes in your mouth.

WEISHAN: It's not just tomatoes, either, of course.

CURWOOD: Uh huh. What other varieties do you have?

WEISHAN: Well, we have all sorts of things. Most of these varieties are actually heirlooms, and as we meander through the garden we can take a look at some of them.

(Footfalls on gravel)

WEISHAN: This one here that did not get well-irrigated, so is not growing too terrifically well, is one of my favorites, called Lazy Wife, from 1810. It's a snap bean that you don't have to pull the string on. You know how, when you snap beans, you have to pull that little string?

CURWOOD: Right.

WEISHAN: Well, this one, the string is fairly edible so you can just snap the beans without pulling it. So it's called Lazy Wife. Next to it is another variety called Vermont Cranberry, which actually has a sort of a white bean. It's a drying bean. It has a beautiful speckling, cranberry speckling to it, which is another terrific store. That was almost lost to modern cultivation except for one man somewhere in Vermont had actually saved some of these beans, and now you can find them in gardens all over the country. They're a terrific bean for soups and stews.

CURWOOD: How well is this biodiversity being preserved, these old heirloom varieties?

WEISHAN: Recently, much more so than in the past. It was only through the efforts of literally a few individuals in this country and in other countries around the world that a lot of these varieties were preserved. And oftentimes they were preserved in the strangest of ways. Things were found growing in old cemeteries, for instances, in the case of roses. Or so and so in Iowa had saved some of her grandmother's tomato seeds. That's how those Brandywine seeds were saved. These seed saver banks have been established in many countries to preserve a lot of these heirloom varieties, principally because it is extremely important to capture this genetic material and preserve it. I mean, the eating benefits are sort of a sideline. For instance, in the 1970s the United States corn crop was threatened with a blight that destroyed about 15% of all the corn in this country. And what had happened was that the modern hybrids had been bred to be non-resistant, to be susceptible to a particular type of virus which the old varieties just brushed off. And they had to actually go back and use some of these heirloom varieties of corn and re-breed the modern hybrids to be resistant to this problem. This happens a lot in plant breeding, that they'll reach back into the past to take some characteristic that's been lost. Fragrance in roses, for instance, has been something that has been lost and now is being re-bred back into roses.

CURWOOD: Where can I get these seeds?

WEISHAN: You can get these seeds in a large number of places. There are many organizations, like Seed Savers Exchange in Iowa, that sell seeds for many of these heirloom varieties. And now many of the modern catalogues are doing so as well: Burpees and Johnny's Selected Seeds in Maine and quite a number. Heirloom gardening has become quite the rage these days.

CURWOOD: Well, Michael, thanks for letting us stop by today. And get a bit of lunch, huh?

WEISHAN: My pleasure, Steve.

CURWOOD: When he's not chatting with us in his garden, Michael Weishan is editor in chief of Traditional Gardening. And Michael will be happy to answer any questions you might have for him about heirloom plants. You can reach him via the Living on Earth web site. Go to www.loe.org. That's www.loe.org. And click on the picture of the watering can.

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CURWOOD: You're listening to NPR's Living on Earth. I'm Steve Curwood.

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ANNOUNCER: Funding for Living on Earth comes from the World Media Foundation Environmental Information Fund. Major contributors include the Ford Foundation for reporting on environment and development issues; the William and Flora Hewlett Foundation; Stonyfield Farm, makers of pure all- natural organic yogurts and ice cream. 1-800-PROCOWS for Stonyfield's Moosletter; and Jennifer and Ted Stanley.

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NPR ANNOUNCER: This is NPR, National Public Radio.

CURWOOD: The hazards of using certain kinds of plastic to seal the teeth of children. The dental sealant controversy coming up on Living on Earth.

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SECOND HALF HOUR

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CURWOOD: It's Living on Earth. I'm Steve Curwood.

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The Living on Earth Almanac

CURWOOD: A hundred and ninety one years ago this week, Meriwether Lewis and William Clark returned from their famous trek into the uncharted West. They had left more than 2 years earlier under orders from President Thomas Jefferson to find an all-water route to the Pacific Ocean. They didn't find the Northwest Passage, but they did find plenty else. Believing that mastodons and other prehistoric creatures still roamed this vast uncharted territory, the President had told the 2 explorers to be on the lookout for unfamiliar animal and plant species. Lewis and Clark recorded detailed observations of 40 mammalian species, as well as more than 50 kinds of birds, 14 reptiles and amphibians, and 12 fish. Of these, nearly a quarter were new to Western science, including the mountain lion, the grizzly bear, and even the harbor seal. The men returned East, but it took 8 years to put their findings into print. By then, most people had lost interest. But not everyone. Trappers swarmed to the Missouri River when they learned of the beavers and other fur-bearing animals Lewis and Clark described there. And as a result, the fur trade flourished for decades. And for this week, that's the Living on Earth Almanac.

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Dental Bonding: Dangerous to your Health?

CURWOOD: Researchers continue to find more and more synthetic chemicals that appear to mimic or inhibit hormones and other chemical messengers in our bodies. The results can range from reproductive and neurological disorders to certain kinds of cancers. And these chemicals are everywhere, it seems in the environment. They are found in our lakes, at the grocery store, and as Brenda Tremblay reports even at the dentist's office.

(Water suction)

TREMBLAY: Thirteen-year-old Alex Tilton got out of school early today to come to the dentist. Alex leans his lanky body into a padded chair and opens his mouth. Dental hygienist Debbie Vitalone polishes Alex's teeth with pumice. Then she applies and rinses what looks like blue toothpaste on his molars in order to prepare them for an application of dental sealant, a permanent plastic coating that will prevent him from getting cavities.

VITALONE: And then we just paint it. This right on the top of the tooth. And what it does, it gets in all those little grooves, covers the top of the tooth.

TREMBLAY: It's clear.

VITALONE: Yeah, clear, tooth color. Okay? And then we just use our light, some ultraviolet light we just put on there.

(Metal clanks. A fan whirrs)

VITALONE: And that hardens them.

TREMBLAY: During the past several years the American Dental Association has been campaigning hard to promote the use of dental sealant. By the year 2000, ADA officials hope that half of all children in the United States will have sealant applied to their teeth. But a team of researchers at the University of Grenada in Spain and at Tufts University in Boston began to wonder what was happening to the plastic going into people's mouths. They asked 18 people who were treated with dental sealant to spit into cups an hour after the sealant was applied. Then the researchers analyzed the saliva and reported significant amounts of an estrogen mimic called bis-phenyl A had leached into the patients'
saliva.

SONNENSHEIN: Nothing will happen specifically after they are treated. The issue is whether it is desirable that we are exposed to estrogen mimics that stay with us.

TREMBLAY: Carlos Sonnenshein of Tufts University in Boston co-authored the study published in the journal Environmental Health Perspectives. He says that in laboratories, human breast cancer cells treated with bis-phenyl A have proliferated 6 times faster than control cells. Bis-phenyl A has also been shown to be toxic to fish, and experiments show it hinders the reproductive abilities of mice, resulting in smaller litters and slower sperm in male mice. Dr. Sonnenshein says there's a human connection, too.

SONNENSHEIN: There are arguments and statistics that indicate that there is an increased incidence of testicular cancer, due probably to the presence of these xeno-estrogens. And the other, still as important, issue is the problem of lower sperm counts. These are studies that require not only confirmation, but amplification, and good controls.

TREMBLAY: At first, the Grenada/Tufts University study on dental sealants merely raised a few eyebrows at the American Dental Association. ADA officials responded with a statement saying the organization did not believe it was necessary to change its recommendation concerning the use of dental sealants. At the same time, they asked their researchers to conduct their own experiments in an attempt to confirm the results from Europe.

MYER: We have not been able to replicate the study or get the same results that that study got.

TREMBLAY: Dan Myer is associated executive director of the Division of Science at the American Dental Association. He says that the researchers in Spain did not study brands of sealant commonly used by American dentists. Dan Myer says researchers at UCLA examined 7 dental sealants that are commercially available in the United States and they could not detect any bis- phenyl A in any of them. While Mr. Myer and his colleagues at the ADA trumpeted the safety of American-made sealants, they also began limiting their approval of dental sealants to those without bis-phenyl A. In other words, the American Dental Association found the European study important enough to act on, even without confirmation of the results.

MYER: As long as this has been raised as a national issue, a national concern, a public health issue, we will continue to look at it until we have exhausted every avenue. And again, we're very concerned about the safety of te public, the safety of our providers. And we will continue to look at that.

TREMBLAY: Out of the 30 brands of sealant currently available to US dentists, only 13 have been tested for bis-phenyl A and approved by the ADA.

VITALONE: Just rinse it out and then I can [obscured by suction]. Rinse out real good, okay? [More suction]

TREMBLAY: Debbie Vitalone is just about finished applying dental sealant to her young patient's teeth.

VITALONE: Okay, let's see, we'll show dad over here. Okay, we did these 2 teeth on this side, and normally the tooth would have grooves in it.

SAM: Mm hm.

VITALONE: Okay. Can you see? It's all smoothed off.

SAM: It's all filled up with plastic.

VITALONE: Mm hm.

TREMBLAY: While his father Sam watches, Alex sits up in his chair and clicks his teeth together. Then he makes a face.

ALEX: It feels like where the plastic is, it's sticking up. And it hits my top teeth. And it just feels sort of like there's a stone in there, or crunchy. And but she said that's going to wear down.

TREMBLAY: Alex will come back about every 3 years to have the sealant reapplied to his teeth. And if he brushes and flosses regularly, his dentist, Dr. Robert Dolan, says he may never need a filling. Dr. Dolan is totally confident that sealants are safe.

DOLAN: There's been so much research in the United States, when they've had dozens and dozens and dozens and they followed it for 10 and 15 and 20 and 25 years, that I think that it wouldn't bother me if one researcher in Spain, unless I saw many, many reports that it was not safe for any reason.

TREMBLAY: Robert Dolan's enthusiasm for dental sealants is shared by a growing number of dentists in the United States. But Dr. Dolan only uses sealant that has been tested for the presence of the estrogen mimic. Not all dentists do. Dan Meyer of the American Dental Association recommends parents talk to their children's dentist and find out if the sealant he or she is using is approved by the ADA. For Living on Earth, I'm Brenda Tremblay in Rochester, New York.

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CURWOOD: If you eat fish, you've probably tried some of that remarkably fresh farm-raised salmon. But you may not have thought about what fish farming can do to our ecosystems. Find out more, just ahead on Living on Earth.

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Salmon Farming: The Down Side

With the numbers of wild fish plummeting around the world, fish farming is often touted as a good way to satisfy demand. And it's already big business. Now, just about half of the salmon sold in this country is raised in pens, set out in coastal waters. But some say that as aquaculture has grown, too many fish farms operate in ways that hurt the environment and pose health threats to humans. As Bob Carty found out, nowhere are concerns more pointed than in British Columbia, the world's fourth largest producer of farmed salmon.

(Water splashing. Bird calls. Large splash)

VERNON: What we're seeing is a very brightly colored silver fish. If you look at them as they come out of the water, you'll notice that their belly is quite white. Their backs tend to be a bluey-gray color, and they've all got the same colored eyes. They're all blue-eyed.

(Gulls call)

CARTY: Bill Vernon stands on a platform floating atop the black waters of Clayoquot Sound off the west coast of British Columbia's Vancouver Island. The tides ebb and flow here through one of the most beautiful fjords in Canada. An old growth rainforest rises up behind us. You wouldn't know it, but this is prime farm territory.

VERNON: This farm is made up of 24 pens and the pens are 15 meters square. And hanging within the steel framework is some netting that is hanging down into the water about 15 to 16 meters. This pen, particular pen, holds about 6,000 fish.

CARTY: Bill Vernon is the general manager of Creative Salmon, a multi-million dollar operation that sells these blue-eyed fish in New York, San Francisco, Tokyo, and Hong Kong. He's part of an industry that went from almost nothing in 1980 to being British Columbia's leading agricultural export today. A hundred forty million dollars a year in sales. The success is partly because restaurants love farm salmon. While some say it doesn't taste as good as wild salmon, chefs can count on a year-round supply of fresh fish of a uniform size and appearance. Add to that the American consumer's craving for low-fat protein. US demand for British Columbia farmed salmon has grown 700% in the last decade.

(Commercial music and man's voice-over: "Fresh salmon has a reputation as America's most wanted seafood. And for years, our American neighbors have enjoyed the delicious, unforgettable flavor British Columbia salmon brings to the table."

CARTY: As this industry promotional video suggests, the British Columbia salmon farming business is hungry for expansion.

(Video continues: "America's most wanted seafood is never caught. It is raised.")

CARTY: But there is a problem. Two years ago the provincial government stopped issuing salmon farm licenses. No more farms until it finished an environmental impact assessment. That move ignited a highly polarized debate. On one side, environmentalists, native groups, and fishermen, who say they're not against fish farming per se, just the way it's done here. On the other side, the salmon farmers. Not your mom and pop kind of family farm, but 7 big companies, many of them multinationals, which control 80% of production. Each side in this debate is armed with voluminous reports, all on recycled paper, citing scientific proof that salmon farming is safe or unsafe. Environmentally benign or harmful. Over-regulated or under-regulated. Life is not so simple down on the fish farm.

(Splashing and shoveling)

VERNON: Right now we're watching one of the employees toss some feed to the fish. We feed in the morning, get as much feed in as we can because feed in means larger fish. These particular fish go in, they're around 15 to 20 grams, and they'll be ready for harvest in about 14 months at 3 kilos or so.

CARTY: At Bill Vernon's farm, the water churns as 6,000 salmon, each almost an arm's length long, chase after the food pellets. The feed is a highly-guarded recipe, sometimes supplemented with drugs and antibiotics. It's mostly made up of fish meal that comes from waters off Peru. And that's the subject of the first controversy at fish farms. Jim Fulton is executive director of an environmental research organization, the David Suzuki Foundation. He calls salmon farming a net loss.

FULTON: There is actually a net loss of protein. What the salmon aquaculture industry performs is the diversion of very high quality human consumable food from one part of the planet where they're poor, South America, to an area where people are wealthy, British Columbia, and then don't feed it to Canadians, pop it on an airplane, and fly it down to Los Angeles or New York.

CARTY: Salmon farmers respond that this kind of argument could apply to all livestock farming. Greg Davignon is the executive director of the British Columbia Salmon Farmers Association.

DAVIGNON: Farmed salmon are the most efficient users of meal of any agricultural product in the marketplace. Some groups that would choose to oppose this industry do so with misinformation, or with emotional rhetoric. Salmon farming as it's currently practiced in British Columbia presents a low probability of risk, of adverse effects to the BC Environment.

CARTY: The aquaculture industry likes to think of itself as just another kind of farming: on water instead of land. But there are differences. Fish farms invite predators. Each year salmon farmers shoot or kill 500 seals, up to 50 sea lions, and uncounted numbers of diving birds. And these ocean feed lots, each with tens of thousands of salmon, leave a bit of a mess in the water around and underneath the net cages. And the farms sit on public, not private, property: the ocean. If soil farmers can't dump animal sewage on public lands, why should salmon farmers? Jim Fulton.

FULTON: They're producing the same amount of sewage every day as a city of 500,000 Canadians. So you've got feces going down below, you've got drugs going down below, you've got disease pathogens escaping out of the cages, you've got salmon escaping out of the cages. It's like a giant prison system where, you know, the guards have gone off work and the inmates have taken over.

(Water splashes. Gulls cry.)

CARTY: Native groups along the west coast are concerned that waste from fish farms is tainting the shellfish they catch. There's also a worry about the farm salmon interacting with wild salmon. Most farm salmon is not native to these waters. They are Atlantic salmon, imported as eggs because as they grow they are more docile than Pacific salmon. They cope better with the stresses of the net cages. But over the years more than a million Atlantic salmon have escaped the farm into the wild. Katherine Stewart is the oceans and fisheries campaigner for Greenpeace Canada. She maintains that escapees from fish farms could cause the genetic pollution of wild Pacific salmon stocks.

STEWART: Each individual run of salmon is genetically unique. They've adapted to their stream of origin. Now, if you introduce 60,000 farm fish who start breeding, there's every possibility that they could become dominant in that stream and they could be the ones to successfully breed and they could be the ones successfully foraging for food, and basically eradicating the wild stocks, the natural stocks. So you're effectively creating a monoculture of non-indigenous to that stream.

CARTY: That's a concern from Puget Sound to Maine to wherever there is both fish farming and wild fish. In Norway, the world's leader in salmon aquaculture, farm salmon now outnumber wild salmon by 4 to 1 in many streams and rivers. Genetic diversity has been reduced. But west coast salmon farmers point out that here, escaped Atlantic salmon have to compete with the more aggressive Pacific varieties. None of the Atlantics have yet been found spawning in Canadian streams. But some scientists say it's only a matter of time, especially as over-fishing weakens the stocks of Pacific salmon. Another part of the debate about farm salmon is the issue of disease. Katherine Stewart of Greenpeace.

STEWART: Fish farms cram 60, 80,000 salmon in a pen in very densely-packed conditions. The salmon are stressed, this is not their natural habitat at all. You're taking a highly-migratory species and confining it to a very small, little pen. So there are outbreaks of disease, and there are antibiotics used to treat those diseases. In Norway the government has deliberately poisoned, with the pesticide rotenone, 24 rivers, wild salmon rivers, because of the spread of sea lice from farm fish to wild fish. The government felt they had no other choice but to kill every living thing in the river and try to start all over again.

DAVIGNON: Again, this is the emotional nonsense that's put out by opponents that would see this industry undermined. They're referring to something called gyrodactylus. Gyrodactylus in Norway was imported with live fish by the state for enhancement purposes. You cannot import live salmon into Canada. You can only import eggs. They're brought into quarantine in Canada and tested 4 separate times for disease. They're surface disinfected, so in that instance gyrodactylus is something that would never come into British Columbia.

CARTY: Salmon farming spokesman Greg Davignon's counter-argument is true, but not failsafe. Eggs disinfected on the surface can carry foreign diseases inside. But the greater concern is that the salmon net cages, dense with fish, food, and feces, are perfect places for native diseases. Those diseases could be passed to wild fish swimming by, and that worries Julian Davies, who heads the Department of Microbiology at the University of British Columbia.

DAVIES: It's like a childcare center. We all know that our children get one of them gets a cold, the whole school gets a cold. And it's the same thing with a fish farm. One of them gets a virus and they all get the virus. And providing that they are kept in the pens and things like this, then I, there's not a problem. But if the fish get out and they infect the wild salmon, then that's clearly a major problem, and that could affect, you know, the fish stocks for some time.

CARTY: Microbiologist Julian Davies says salmon farming may even pose dangers to humans because of the use of antibiotics to fight infections in the net cages. The industry points out that it is reducing the amount of antibiotics it uses. Instead, fish are vaccinated against diseases. And in relative terms, many more antibiotics are used in human medicine and agriculture than in fish farming. But Julian Davies is still concerned. The antibiotics used in fish are also used in humans. So Dr. Davies worries that bacteria on fish farms could transfer their antibiotic resistance to bacteria that affect humans.

DAVIES: Humans could acquire this just simply by handling fish. Eating it is not so much of a problem. I mean, if you cook it, it's all right. I sometimes wonder about sushi, seriously. (Laughs) I don't eat sushi, myself. There is a finite possibility that people could ingest antibiotic-resistant organisms. Now, those organisms are not going to be pathogens to the human host, but they can transfer their resistance to the human host, and that's the thing that we're really concerned about.

CARTY: The environmental challenges of salmon farming have been studied by British Columbia's Environmental Assessment Office. It just submitted a massive, 1,800-page report to the government, recommending that salmon farming be given a yellow light: allowing it to expand but with caution and conditions. Those conditions include better siting of fish farms, the protection of shellfish from farm wastes, a reduction in the number of mammals killed, and overall, much better regulation. The report calls for more research on the issues of escaped fish, disease transfer, waste disposal, and antibiotic use. The Suzuki Foundation's Jim Fulton welcomes the report, but it didn't go as far as he would have liked.

FULTON: Salmon farming must be regulated with closed loop systems. Those are hard-sided tanks that can float in the ocean, where you completely contain feces, sewage, drugs, disease pathogens, and the fish themselves. And while you're doing that, it also means that the sea lions and seals and otters and diving birds won't be killed by the sea farms, by going to a technology that is available now, and it's cost-competitive.

(Mechanical sounds)

VERNON: Out on the end of the dock here you see our processing plant. We bring the fish in here and unload them here, and then they're gutted and gills are removed. And they're stowed in totes in ice and sent off to market.

CARTY: In the town of Tofino, on the waters of Claquad Sound, Bill Vernon shows off his company's processing plant. Fish leaving here today may tomorrow be on the menu of a fine restaurant in San Francisco. Salmon farmers say that if the government gives them a green light, they could invest millions of dollars that could increase production 5-fold in a matter of years. But native groups say they'll fight new salmon farms with civil disobedience if necessary. Environmentalists still want more controls. And fishermen complain farm salmon will hurt the wild catch. Salmon farming is turning out to be a messy kettle of fish. For Living on Earth I'm Bob Carty in Tofino, British Columbia.

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CURWOOD: It's Living on Earth. I'm Steve Curwood.

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(Gunshots, broken glass, more gunshots, people yelling)

Fire Down Below

CURWOOD: Oh yeah, a guns and guts movie, the kind that Hollywood loves. Not exactly my taste, but the recent box office success of the new flick Fire Down Below shows that formula can even be applied to environmental themes. Living on Earth's private eye at the movies, Constantine von Hoffman, has our review.

VON HOFFMAN: Truth be told, I'd rather watch a Sierra Club remake of Die Hard than sit through another Hollywood attempt to depict threats to the environment. Even perennial green guy Robert Redford has so far spared us Global Warming: The Movie. Any doubts I had about this were laid to rest after taking in Steven Seagal's latest action adventure flick Fire Down Below.

Seagal plays Jack Taggart, a martial arts expert who runs around with a large gun strapped to his side as he upholds the rules and regulations of the Environmental Protection Agency?

(A punch. Woman: "Who are you?" Seagal: "I'm a Federal agent.")

VON HOFFMAN: After several of his EPA buddies are killed investigating a toxic waste dump in Appalachia, the Feds send in avenging angel Seagal to, yup, clean up the town. I'll spare you further details; they'd only make your head hurt. Suffice it to say there's scene after scene of our hero decked out in the latest black fashion: think Johnny Cash meets Rodeo Drive. And he's traipsing around the hills of Kentucky beating up bad guys, flirting with blonde beauties, pouring water into test tubes and shaking them up and down, all in the search for pollution. That technical wizardry apparently blinds Seagal to the painfully obvious: one of the locals has to point out to him that all the fish floating in the stream are dead. Check the source, Jack.

Meanwhile, the evil corporate tycoon, played for laughs by Kris Kristofferson, is corrupting everyone and everything as he tries to get a shipment of cyanide-laced chemicals into his dump. No matter what your politics you wind up rooting for Kristofferson. He's the film's only likeable character.

(A helicopter whirrs. Kristofferson: "I made $16 million on this deal. You think I'm giving it back?")

VON HOFFMAN: In the middle of all this are agonizing speeches about the horror of corporate greed an ineffectual government enforcement. Perhaps the only interesting thing about Fire Down Below is its ability to mesh right- wing anti-government paranoia and a call for more environmental regulation into one character. In the final showdown between good and evil, Seagal finally loses his cool.

(Seagal: "The EPA, they've never been very good at punishing criminals, catching them." [Western-style tense showdown music] "Catching them. Helping the environment. I've got a surprise for you. I quit the EPA, and I quit the EPA so I could spend my every waking moment trying to make your life miserable." Kristofferson: "We played this one by your rules, and your court decided I was clean. You're violating my constitutional rights." Seagal: "Mr. Hanner, I promise you, sure as you stand here now, I'm going to show you a new meaning to the word violation.")

VON HOFFMAN: As you can hear, logic isn't this movie's strong suit. And what we're left with is a film that combines the worst of 2 disparate worlds: the humorless preachiness of a particularly irritating brand of environmentalist, and Hollywood's inability to make a good action movie. My advice? If you want to be enlightened about the environment, take a walk in the woods. Go to the beach. Just stay out of the theaters. As the late Hollywood mogul Louie Mayer said, if you want to send a message, call Western Union. For Living on Earth, I'm Constantine von Hoffman.

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CURWOOD: And for this week that's Living on Earth. Our production team includes Liz Lempert, Daniel Grossman, Jesse Wegman, Julia Madeson, Peter Christianson, Peter Shaw, and George Homsy. Our associate editor is Kim Motylewski. Peter Thomson heads our western bureau, and Chris Ballman is the senior producer. We had help from Dana Campbell and bid a fond farewell to intern Emma Hayes. Jeff Martini engineered the program; Michael Aharon composed the theme. Our program is produced by the World Media Foundation in cooperation with Harvard University. I'm Steve Curwood. Thanks for listening.

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ANNOUNCER: Funding for Living on Earth comes from the World Media Foundation Environmental Information Fund. Major contributors include the William and Flora Hewlett Foundation for reporting on western issues; the W.K. Kellogg Foundation for coverage of sustainable agriculture; the Geraldine R. Dodge Foundation; the National Science Foundation for coverage of science in the environment; and the W. Alton Jones Foundation.

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