NEXT PAGE -->
|
ANOTHER PESTICIDE SURPRISE
The decline and disappearance of frog populations worldwide remains a mystery, despite efforts by hundreds of scientists to determine the causes. (See REHW #380, #441.) The other major problem facing frogs --massive deformities observed since 1995 among frog populations in California, Iowa, Minnesota, Missouri, Ontario, Quebec, South Dakota, Texas, Vermont, and Wisconsin[1] --is now better understood. (See REHW #515, #590.)
During the past six months, press interviews with research scientists, and published studies, have shed a bit of light on both problems though true consensus has not yet emerged on either one. No one is even sure whether the two problems are connected, though new evidence indicates they are.
Some scientists still doubt that frogs are actually disappearing worldwide. They prefer to believe that the simultaneous declines and disappearances of frog populations in North and South America, Europe, and Australia reported since 1980 are nothing more than the normal ups and downs of any wild population. However, SCIENTIFIC AMERICAN said in August that the "majority viewpoint" among scientists now is that the widespread declines and disappearances are "highly abnormal."[2] "I think we're close to consensus now," says David Wake, a well-known frog researcher at the University of California at Berkeley.[3]
There are roughly 5000 species of amphibians worldwide. Of these, 242 inhabit the U.S. A recent study by the Nature Conservancy and the Natural Heritage Network identified 92 of these 242 (or 38%) as endangered, imperiled, or vulnerable[2] (meaning they are likely to become extinct within 5, 20, or 100 years if present trends continue.)
James La Clair at the Scripps Research Institute in La Jolla, California, says, "Although amphibians have lived on this planet for over 300 million years, nearly 120 times [as long as] modern man, reports within the last three decades have shown that numerous amphibian species are either suffering from serious population loss or have disappeared altogether."[1] La Clair says there are very likely "a collection of causes," but one way or another they can all be traced back to "the expansion of humankind." Loss of frog habitat --chiefly wetlands --is probably the biggest single cause. Global warming and accompanying droughts may contribute because frogs develop from eggs that thrive in water. The artificial stocking of streams with trout and bass plays a role, too. Pesticides and other chemicals certainly exacerbate the problem (more on this below). Laboratory experiments have shown beyond doubt that ultraviolet light from the sun can interfere with the development of frogs' eggs.[4] Acid rain may contribute to the problem as well. Humans eating frogs' legs in large quantities are not helping. And there are other causes, such as infectious agents.
A group of Australian researchers reported this summer that they have identified one particular fungus that is killing frogs in locations as far apart as Queensland, Australia and Panama in Central America.[5] The fungus --which has never before been reported to harm any vertebrate species --causes changes in the skin of frogs, somehow contributing to their deaths. The mechanism is not understood, but frogs breathe oxygen through their skin and the fungus may cause suffocation.
No one knows why an ancient fungus would suddenly start killing frogs in places as far apart as Australia and Panama. It is conceivable that the fungus was transported to these places only recently on the boots or equipment of researchers studying the disappearance of frogs. Another possibility is that the fungus has been present in these locations for a long time but frogs are now succumbing to it because their immune systems have been impaired by recent changes in the environment. One candidate would be increased ultraviolet light, which is well-known to damage the immune systems of many animals, including frogs. In recent years, chlorinated chemicals released by humans have thinned the protective layer of ozone in the upper atmosphere, thus allowing about 10% more ultraviolet light from the sun to reach the surface of the Earth.[6]
Certain industrial chemicals released into the environment may also be damaging the immune systems of frogs. One particular class of chemicals --called retinoids --has come under strong suspicion because retinoids can cause severe birth defects in many animals, including frogs and humans. The medicine Accutane, prescribed for treating acne, is a retinoid known to cause major birth defects in humans.
The deformities now being found in large numbers of frogs at many locations in the U.S. and Canada are grotesque. Herpetologists (scientists who study amphibians and reptiles) have reported finding frogs with missing legs, extra legs, misshapen legs, paralyzed legs that stick out from the body at odd places, legs that are webbed together with extra skin, legs that are fused to the body, and legs that split into two half-way down. They have also found frogs with missing eyes and extra eyes. One one-eyed frog in Minnesota had a second eye growing inside its throat.
Dr. David Gardiner, a research biologist at the University of California at Irvine, has been studying retinoids for at least a decade, and in recent years he has probed frog deformities.[7] To him, retinoids are the obvious culprit in the mystery of the misshapen frogs because of the peculiar kind of limb deformities being observed. "There is no other known mechanism for this [besides retinoids]," Gardiner says. "Much of early development is controlled by retinoids," he says. "Our body [and the body of a frog] is completely dependent on them," he told a reporter.[8]
Exposure to retinoids could also make frogs more susceptible to infectious diseases, Gardiner says: "The kinds of chemicals that would target development of limbs would target all organ systems," including the immune system. Frogs with abnormal legs would also very likely have abnormal immune systems. This could explain why some frogs are now suddenly falling victim to infectious agents that they resisted for millions of years.
James La Clair and his associates at the Scripps Research Institute in La Jolla, California, recently showed that a popular anti-mosquito insecticide, called S-methoprene, breaks down in the environment to several different kinds of retinoids.[1] Under laboratory conditions, La Clair was able to show that the ultraviolet light in sunlight causes S-methoprene to break down into half a dozen retinoids, and that these retinoids in turn can cause frog deformities of the kind being seen now in the U.S. and Canada.
S-methoprene was introduced in the 1970s to control mosquitoes, which breed in water. It is sold under trade names like Altosid, APEX, Diacon, Dianex, Kabat, Manta, Minex, Pharoid, Precor, Yuvemon, and ZR 515.
It is also widely sold in flea powders. La Clair calculates that the amount of flea power used to treat a ten-pound pet one time contains enough S-methoprene to contaminate 110,000 liters of water to a level that would cause deformities in frogs.[1]
S-methoprene is also widely used in agriculture to treat cattle gazing areas, tobacco, and certain grain crops. It is also sometimes added to cattle feed.
S-methoprene mimics a hormone that inhibits developing pupae from molting; thus it is known as an "insect growth regulator." Because vertebrate species do not have a pupal stage of growth, scientists assumed S-methoprene could not harm amphibians or mammals. When fed to mammals, S-methoprene is about as toxic as sugar.
Now La Clair's work has shown that this seemingly-harmless chemical can be transformed into a potent teratogen by exposure to sunlight for just a few hours. The implications of this research, which was reported in ENVIRONMENTAL SCIENCE & TECHNOLOGY, a journal of the American Chemical Society, are profound. For one thing, it means that once again the pesticide regulators at U.S. Environmental Protection Agency [EPA] have missed a key feature of a chemical whose safety they regulate. Secondly, it shows once again that relying on risk assessment leads to bad public health decisions. EPA's risk assessments have routinely failed to evaluate the breakdown by-products of the pesticidal chemicals that the agency has deemed safe enough to allow as residues on our dinner plates. Third, it means that thousands of pesticides now in common use need to be re-tested to see if their breakdown by-products are dangerous to humans or other species. However, this additional testing is unlikely to occur any time soon because EPA currently estimates that it is at least 15 years behind schedule in safety-testing the pesticides to which we --and the frogs --are currently being exposed.[9]
Indeed, the situation is worse than the agency makes it out to be. Congress ordered EPA to re-evaluate and modernize all pesticide safety tests in 1972, and it demanded that the agency complete the job by 1977. Since 1972 the Agency has been doing its best to comply, but each year new revelations have come to light, new evidence showing that pesticides can harm humans and the environment in ways that no one imagined, so additional tests have been required. Thus La Clair's work is just the latest surprise in a long chain of unpleasant surprises. EPA officials in 1996 estimated that they will complete their pesticide safety re-evaluations (which they were ordered by Congress to complete in 1977) in the year 2011 --34 years late --IF they can keep the work on schedule.[9] Meanwhile the frogs and we continue to be exposed to thousands of poorly-understood government-approved industrial poisons.
In sum, Dr. La Clair's research into the deformed frogs of North America serves to remind us that pesticides are now too dangerous to be safely regulated, even by the most powerful government the world has ever known.
Or is it that PESTICIDE MANUFACTURING CORPORATIONS are now too dangerous to be safely regulated, even by the most powerful government the world has ever known? It's a fair question.
--Peter Montague
Every once in a while the NEW YORK TIMES knocks your socks off showing how the world got the way it is. This past Sunday the TIMES ran "Playing God in the Garden" by Michael Pollan --the cover story in the magazine section.[1] It explains why many of us are already eating genetically engineered foods like corn and potatoes without knowing it, and why there is a lot more genetically engineered food in our future whether we like it or not. It's the story of a powerful corporation on a dangerous mission and a huge government too feeble to intercede. The TIMES story makes these points:
** Genetically engineered food crops have been on the market in the U.S. for four years now. Some brands of corn, potatoes and soybeans are now genetically engineered.
** The nation's food safety authority --the U.S. Food and Drug Administration (FDA) --does not require genetically engineered food crops to be labeled as such, so none of us can know whether the food we are eating is genetically engineered or not. Chances are pretty good that if you eat french fries at McDonald's, or if you eat Frito-Lay potato chips, you've eaten a genetically-engineered potato patented by Monsanto, the St. Louis chemical giant. The TIMES story focuses on Monsanto's New Leaf Superior potato, a thin-skinned white spud found fresh in your supermarket.
** Monsanto's New Leaf Superior potato is, itself, legally registered as a pesticide with U.S. Environmental Protection Agency [EPA] because it has been genetically engineered to poison any Colorado potato beetle that might eat even a tiny portion of it. Every cell of Monsanto's New Leaf Superior contains a gene snipped from a bacteria called BACILLUS THURIENGENSIS, or Bt for short, which produces a protein that is highly toxic to Colorado potato beetles. The Bt gene is present in every cell of a Monsanto New Leaf Superior, which is why the potato itself is registered as a pesticide.
** U.S. EPA [Environmental Protection Agency] has responsibility for licensing new pesticides. EPA pesticide officials believe that the New Leaf Superior potato is reasonably safe for humans. As a test, EPA fed pure Bt to mice without harming them. Because humans have eaten old-style New Leaf potatoes for a long time, and because mice are not visibly harmed by eating pure Bt, potatoes containing Bt genes must be safe for humans, EPA reasoned. The TIMES reported, "Some geneticists believe this reasoning is flawed" because inserting foreign genes into plants may cause subtle changes that are difficult to recognize. Only time will tell.
** The label on a bag of Monsanto's pesticidal potatoes in the supermarket lists all of the nutrients and micronutrients in the potato, but fails to mention that the potatoes have been genetically engineered or that they are legally a pesticide. Food labeling is ordinarily the responsibility of FDA.
** An FDA official told the NEW YORK TIMES that FDA does not regulate Monsanto's potato because FDA does not have the authority to regulate pesticides. That is EPA's job.
** EPA-approved pesticides normally carry an EPA-approved warning label. For example, a bottle of Bt bears a label that warns people to avoid inhaling Bt and to avoid getting Bt in an open wound. However, in the case of Monsanto's pesticidal potato, EPA says FDA has responsibility for requiring a label because the potato is a food. However, FDA told the TIMES that it only requires genetically-engineered foods to be labeled if they contain allergens or have been "materially changed" and FDA has determined that Monsanto did not "materially change" the New Leaf potato by turning it into a pesticide. Therefore no FDA label is required. Furthermore, the law that empowers the FDA (the Food, Drug and Cosmetic Act) forbids FDA from including any information about pesticides on food labels. Pesticide labels are EPA's responsibility, says FDA, and we come full circle.
** Some genetically-engineered food crops are NOT registered as pesticides, and FDA DOES have the authority to regulate those. However, according to the TIMES, FDA maintains a list of foods that need no regulation because they are "generally recognized as safe" (or "GRAS"). Since 1992 FDA has allowed companies like Monsanto to decide for themselves whether their new genetically-engineered foods should be added to the GRAS list and thus escape regulation. In other words, FDA regulation of genetically engineered foods is voluntary, not mandatory.
** A Monsanto official told the NEW YORK TIMES that the corporation should not have to take responsibility for the safety of its food products. "Monsanto should not have to vouchsafe the safety of biotech food," said Phil Angell, Monsanto's director of corporate communications. "Our interest is in selling as much of it as possible. Assuring its safety is the FDA's job," Angell said.
In sum, biotech is an industry in the grip of a frontier mentality. Anything goes. Government is a willing and servile participant. If it turns out worse than the chemical debacles of the last 50 years, will anyone be surprised?
** Monsanto's New Leaf Superior potatoes will have major effects on U.S. agriculture, regardless of their human health consequences (if any).
** Organic farmers --those who try to avoid synthetic chemical pesticides and fertilizers to the extent possible --apply powdered Bt sparingly to their crops from time to time, a natural pesticide of last resort. In this powdered form, Bt is neither present in high concentrations nor for very long because it degrades in sunlight. Therefore, insects have not developed "resistance" to Bt.
** But now that Bt is continuously present in whole fields of Monsanto potatoes, the insects in those field will be continuously exposed to Bt. Therefore it is only a matter of time before they develop "resistance" and become immune to Bt's toxic effects.
The mechanism of resistance is well understood because over 500 insects have become resistant to one pesticide or another since 1945. Not every potato beetle will be killed by eating Monsanto's pesticidal potatoes. A few hardy beetles will survive. When those few resistant beetles mate with other resistant beetles, a new variety of potato beetle will spring into being and it will thrive by eating Monsanto's potatoes. At that point, Bt will have lost its effectiveness as a pesticide. Then Monsanto will start marketing some new "silver bullet" to control the Colorado potato beetle. But what will the nation's organic farmers do? For private gain, Monsanto will have destroyed a public good --the natural pesticidal properties of Bt. Monsanto scientists acknowledged to the NEW YORK TIMES that the Bt-containing potato will create Bt-resistant potato beetles. They know exactly what they are trying to do. They are hoping to make a mint selling Bt-laced potatoes and, in the process, depriving their competitors (organic farmers) of an essential, time-honored tool. The strategy is brilliant, and utterly ruthless.
** For decades, Monsanto and other agrichemical companies have relentlessly promoted farming systems aimed at making farmers dependent on synthetic chemicals. With the enthusiastic support and complicity of USDA, the plan worked beautifully. In the U.S., the use of chemical pesticides grew 33-fold from 1945, peaking at 1.1 billion pounds (about 4.4 pounds per year for each man, woman and child) in 1995.1 Now with growing numbers of pesticide-resistant insects, and consumers better-informed about the dangers of pesticide residues on food, Monsanto acknowledges that "current agricultural technology is not sustainable," as their most recent annual report puts it. Now Monsanto is planning to shift American farmers from the pesticide treadmill to a biotech treadmill.
** For thousands of years, farmers have saved a portion of this year's crop to provide seeds for next year's crop. Monsanto intends to end that age-old practice by requiring farmers to come back to them each year to purchase new seeds. Potatoes are not grown from seeds --they are grown by planting "eyes" of other potatoes. Before you buy a bag of Monsanto's pesticidal potatoes you must sign a contract promising that you will not retain any of your potatoes toward next year's crop. This will force you to purchase more potatoes from Monsanto next year. According to the TIMES, Monsanto is using informants and Pinkertons, and has brought legal action against hundreds of farmers, to enforce its contract rights.
To tighten the noose on farmers, Monsanto has a new technology in the pipeline, called "the Terminator."[3] Terminator technology was developed with public funds by U.S. Department of Agriculture (USDA) and a seed company that Monsanto is in the process of buying. The Terminator is a group of genes that can be spliced into any crop plant, sterilizing all of the plant's seeds. Once Terminator technology has been widely adopted, control of seed production will move from the farmer's field to corporate headquarters and farmers will become wholly dependent upon corporations for seeds. As the TIMES summarized it, "The Terminator will allow companies like Monsanto to privatize one of the last great commons in nature --the genetics of the crop plants that civilization has developed over the past 10,000 years." Brilliant and ruthless.
** In a multi-million-dollar advertising campaign in Europe, Africa and the United States, Monsanto claims that its new emphasis on genetic engineering is aimed at feeding the world's hungry and saving the environment from pesticides of the kind it has produced in megaton quantities for the past 40 years.[2] However, the TIMES offered insights into genetic engineering that make Monsanto's new path seem at least as destructive as its old path, and perhaps considerably worse.
** Monsanto says that its genetic manipulations are providing the "operating system" for running a new generation of plants. But the analogy breaks down quickly. A computer operating system, like DOS or Windows or Unix, is fully understandable by the programmers who wrote the code. On the other hand, the genetic code was written by the Creator and no human --or group of humans --understands even a small fraction of it. Putting genetically-engineered plants and animals into the natural environment is nothing more than a crap shoot --one with potential consequences far greater than Monsanto's previous calamitous experiments, polychlorinated biphenyls (PCBs) and Agent Orange.[3]
** The TIMES says that, to create its New Leaf Superior pesticidal potatoes, Monsanto has had to introduce the Bt gene into thousands of potatoes to get it right because often the introduced gene ends up in an unexpected place in the potato's DNA, creating a plant that doesn't have the right pesticidal properties, or one that is an outright freak. "There's still a lot we don't understand about gene expression," says David Stark, co-director of Naturemark, Monsanto's potato subsidiary, in a monumental understatement.
** Richard Lewontin, a Harvard geneticist, told the NEW YORK TIMES that Monsanto's comparison of genetically engineered plants to an "operating system" isn't the right comparison. Instead, Lewontin said, the genetic code is more like an ecosystem. "You can always intervene and change something in it, but there's no way of knowing what all the downstream effects will be or how it might affect the environment. We have such a miserably poor understanding of how the organism develops from its DNA that I would be surprised if we don't get one rude shock after another," Lewontin said.
--Peter Montague
NEXT PAGE -->
|