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Tucked away in some northwestern Pennsylvania swampland is the University’s laboratory of ecology. The research taking place there, headed by Rick Relyea, could change everything the world knows about pesticide safety.

Pest Controls


Kris B. Mamula


Patooey!

The man spits a bit of muck from his lips.

The ingredients from the unwanted taste test came from the bottom of a huge plastic tub. Typically, such tubs are used as troughs to water cattle. But not this one. This tub was being used to accumulate what politely can be described as fetid slurry.

The man has slowly upended the tub in order to drain the goop through a net that he grips in his hand. A few drops splash. Patooey!

How does a grown man come to be splashed with this disgusting stuff while crouching ankle-deep in stinking, bug-infested pond water on a remote Pennsylvania farm?

In a way, education is to blame. Higher education began for him at community college. He’s the first in his family to go to college. Now, at age 37 and with a stack of college degrees, this son of a carpenter found himself asking his wife of just a year whether she minds if he shaves his head before his trip to the farm. He wanted to do so to prepare for the mosquitoes. The bugs can get real bad around Pymatuning Reservoir, which for most of recorded history has been best characterized as a swamp.

His wife didn’t mind. She understands.

She understands her husband’s passion for vile pond water, for cattle watering tubs that attract nesting yellow jackets, for roads with no names, for ball caps worn frontward, for Hank Williams, and for places utterly devoid of Starbucks. After all, they met on a trip to find new aquatic life, high in the remote mountains of South America’s Patagonia.

The University of Pittsburgh’s Pymatuning Laboratory of Ecology takes its name from a speck of a town about two hours north of Pittsburgh. A few miles away, back down a dirt road, is a 130-acre spread dubbed simply “The Farm.” The farm is the newest extension of the lab. Here is where the man chose to spend his summer with seven students. They are doing plant and animal experiments. The experiments involve tadpoles and stuff advertised to kill bugs and weeds. Welcome to Rick Relyea’s laboratory. It’s as big as all outdoors.

Standing in a muddy field, Relyea gazes at two buildings in the farm’s immediate horizon. He marvels. It’s as though the buildings—which house gleaming microscopes, centrifuges, computers, and ample floor drains—are still a dream to him. Despite the less than glamorous setting, he thinks himself most fortunate.

As for what’s going on inside those big tubs at the farm, Relyea, professor of biological sciences, is harder to read. Like many men who grow up in towns too small for a traffic light, Relyea marks his words. He concedes that something curious is happening. Pressed on the issue, Relyea, ever the scientist, will only say more information is needed. It may be appropriate for others to jump to conclusions, he says. But that would not be appropriate for him. It would not be appropriate for his students. He’ll tell the students, you’re not here to know; you’re here to find out. “We’re trying to be scientists, not policy makers,” he says.

It’s no wonder Relyea chooses his words carefully. The results of his experiments, if accurate, could change everything we know about pesticide safety.

Members of the Native American Erie Nation were the first recorded inhabitants of Pymatuning, which means “crooked-mouthed man’s dwelling place,” according to the Commonwealth's Department of Conservation and Natural Resources. The name is believed to have originated from an Erie Nation queen. She was known for her cunning and dishonesty. Her disposition may have had something to do with where she lived.

Back then, the region was a vast swamp. Mosquitoes swarmed by the bazillion. Still do. Early White settlers identified another problem. The swamp swallowed stray cattle.

Pymatuning Laboratory of Ecology is the field research station for Pitt’s Department of Biological Sciences. The lab is located on the shores of Pymatuning Reservoir, within some 11,000 acres of water, wetlands, and forest. The Pennsylvania Game Commission manages the land for migratory waterfowl, but it’s off limits for public recreational uses. Pitt has had a biological field station in northern Pennsylvania since 1926. The current facility dates to the 1950s. The farm was added to the University’s research facilities three years ago.

Build ark. Gather animals. The day’s agenda for Relyea’s group is printed in formal block letters on a marker board inside a building at the farm. Rain has been falling here steadily for weeks. But the experiments must not be delayed. Each one is time-sensitive. Thirty tubs will be drained and the water analyzed today, rain or shine. All told, some 9,000 gallons of pond water will be filtered and filtered again. The water, which is filtered by hand, is roughly equivalent to what an average family uses in a month.

From the murk inside the tubs, Relyea and his students will carefully fish out tadpoles and a couple different kinds of tadpole predators. The surviving creatures will be counted and weighed and the data recorded in a log.

The nastiest predator is called dytiscus, pronounced die-TISS-cuss. The dytiscus has the curled tail and pincers of a scorpion. He attacks with stunning ferocity. The other predator is the salamander-like newt. Despite appearances, he, too, regards tadpoles as little more than lunch.

The experiment ending today began three weeks ago. Each tub was lined with sand or clay, then generously seasoned with rotting leaves. The idea was to make artificial ponds. Three kinds of tadpoles were added to the water: leopard frogs, tree frogs, and toads. They look pretty much the same, except for size. Next, the predators were added to the mix. All the animals were added in proportion to what might be found in a real pond.

For the last ingredient, Relyea says he went to a Wal-Mart and determined the best-selling pesticides based on the most shelf space devoted to various brands. His ultimate choice was carbaryl, which is pronounced CARB-a-rill. It’s sold as Sevin.

His pick was on target. Carbaryl is among the most commonly used pesticides in the world. For the farmer, carbaryl keeps cucumbers, tomatoes, lettuce, blackberries, and other crops free of bugs. For the home market, carbaryl in pet collars keeps fleas off Rover and lawns free of slugs and snails. Insecticides like carbaryl are part of a $33.5 billion world pesticide market, according to the most recent estimates by the federal Environmental Protection Agency. In North America alone, the EPA reports that carbaryl is used in some 28 million homes and 31 million gardens.

The amount of carbaryl Relyea says he added to the tubs was well within manufacturer’s guidelines. Carbaryl is not recommended for use in ponds or lakes, but the dose was comparable to what could be expected in a stream after a nearby field is sprayed.

Carbaryl kills by interrupting nerve impulses, but it breaks down soon after being absorbed into soil. What’s more, it doesn’t accumulate in animal tissue. Since it was introduced in the late 1950s, “generally speaking, it has had a pretty good environmental safety record,” says Winand K. Hock, professor emeritus, Pennsylvania State University, and former director of Penn State’s pesticide education program.

Relyea also bought two other popular pesticides for tests in separate tubs. One was glyphosate, pronounced GLY-pho-sate, sold as Roundup. Glyphosate, the world’s most popular weed killer, kills thistle and dandelions in the backyard. Commercial uses include weed control in utility right-of-ways, roadsides, and rail lines. The sale of glyphosate is part of a $14.6 billion world market for weed killers, according to the EPA.

Relyea’s experiments are the first ever to test glyphosate toxicity in North American amphibians like tree frogs. Amphibian populations have been declining in some parts of the world. Examples include Australia, South and Central America, and high-altitude regions of western United States. Experts blame the amphibian decline on a number of things, from loss of habitat to harmful sun rays caused by ozone layer depletion. But Relyea is the first to test whether glyphosate may also be a factor. The idea sprang from simple scientific curiosity, Relyea says. He is also the first to test pesticide toxicity in a more natural environment, that is, one with predators in the water.

Pesticide makers are required to test their products. They must figure out the toxicity of every bug and weed killer. Then, the EPA must approve these findings before the chemical can be marketed. Relyea says manufacturers do their standard testing slowly by adding the chemical to a tub containing, say, fish, then figuring out how much is needed to kill half the fish within a given period of time. The trial usually lasts two to four days.

Relyea considers those conditions “highly artificial,” partly because predators are not part of the mix. There are some 21,000 chemical pesticides on the market—and counting. Adding predators to every batch would drive up the cost of testing, though Relyea says predators would create conditions far more likely to be found in nature.

Here’s why Relyea believes the presence of predators may be important. In 1999, he and colleagues found that predators in the test water boosted carbaryl’s toxicity to a much more deadly level when compared to carbaryl alone in the water.

Exactly why carbaryl and the presence of predators create such a toxic stew is starting to be understood. Once upon a time, biologists believed that tadpoles lived simple lives. They ate and gave predators a run for their money. About 10 years ago, that thinking changed. “Now, we know they’re way more complicated than that,” Relyea says.

For example, biologists know that tadpoles are keenly aware when an enemy is near. They also know how many and what kind of predator it is, and what it just had for lunch. Researchers like Relyea believe many forms of aquatic life “smell” predators in the water through some kind of chemical communication.

As for Relyea’s toxicity findings, he can’t provide an explanation yet, saying only, “It’s the synergy of the two together, pesticide and predators, which makes it so deadly.”

According to Relyea’s study, today’s acceptable levels of carbaryl could “devastate many frog populations.” He adds, “Safe levels of some pesticides are not safe when predators are in the pond.” If he is right, “these negative impacts may be widespread in nature” because of the sheer number of similar pesticides used today.

People are taking notice of Relyea’s research. His first carbaryl findings were published in 2001 in Proceedings of the National Academy of Sciences, which is among the world’s most cited multidisciplinary scientific journals. The study was the first to link chemical toxicity to the presence of predators. “Rick really opened the door to all this stuff,” says April Randle, a doctoral student who is studying with Relyea. “He really hit on something.”

Relyea’s collaborator on the first carbaryl study, Nathan Mills, agrees. “No one had ever shown that a predator had somehow interacted with the chemical,” says Mills, who is an assistant professor of biology at Harding University in Searcy, Ark. “When you look back now, you say, ‘That makes sense.’ But no one had done it.”

Working with other Pitt researchers, Relyea thinks he will be able to identify the “smell” aquatic life use to understand their surroundings. The National Science Foundation thinks so, too. The NSF is backing the search with a $100,000 grant. What’s more, the NSF promised another $400,000 to find other communication chemicals after the first one is found.

Relyea’s approach to this project spotlights the University of Pittsburgh’s unique strength in biological sciences. Pitt’s department is fully integrated, which means many kinds of specialists work under one roof. Here’s an example:

Relyea, an aquatic ecologist, will be working with biochemist John D. Hempel and molecular biologist Roger Hendrix in trying to identify the chemicals used in amphibian communication. Hempel is also a research associate professor, and Hendrix is a professor in the department. Past department chair James M. Pipas says collaboration within biological sciences is the wave of the future.

During the past 30 years, many universities had encouraged specialization in the sciences. Botany, microbiology, and molecular biology are examples. Walls inevitably grew up around these subspecialties, stifling collaboration, and ultimately preventing a full understanding of the world and its creatures.

Such divisions may have been useful at one time, says Graham Hatfull, who is the department’s Eberly Family Professor. No more. “There has been, and we are continuing, a very profound revolution in the natural sciences.” This revolution requires increased cooperation among various specialties within biology, says Hatfull, who assumed the department chair in July.

“This is something many universities are trying to reinvent,” adds Pipas, who is also a department professor. Hempel agrees. “Broad-based biological sciences are less and less common in large universities,” he says. “Here, everything biological is in the same department.”

Increased collaboration has helped boost research dollars reaching the department, according to Pipas. Research funding has steadily risen in recent years, and this year, the department received $6.7 million. In addition to citing increases in research money, Pipas, Hatfull, and others also say the department’s success can be measured by the caliber of graduate students and faculty who continue to be attracted to Pitt’s program. For example, Randle, the doctoral student, says she was first drawn to the University after reading about Relyea’s studies.

The forecast is correct. A gray afternoon turns rainy in a sloppy field where the students are working. “Well, that was bad luck,” Stacy Phillips sighs, as she strains the last few drops of pond water from a tub roughly the size of those used in restaurants to collect dirty dishes.

Phillips, a sophomore biology student, and the other students stand in the rain as they diligently drain and filter pond water. They can’t help but notice that few or none of the 60 creatures added at the start of the experiment three weeks earlier are found in the pesticide-treated water. Meanwhile, untreated tubs teem with critters.

“We all expected a fair amount of mortality,” says Jason Hoverman, a second-year graduate student whose interest in biology was sparked by watching the Discovery Channel as a child with his father. “But none of us expected to see it to such a degree.”

It has long been believed that dirt somehow helps absorb the pesticide before it hurts aquatic life. Although today’s test results are still being analyzed, the sand and soil seem to have done little.

A 10-year-old boy is spraying bug killer in a potato field. The sun is shining, and the weather is warm. The pesticide is killing potato bugs that feast on plant leaves. Wearing shorts, he walks up and down the rows, pumping a hand-held sprayer. The airborne pesticide soon coats his legs. He doesn’t think anything of it. No one else does, either. This is perhaps Relyea’s earliest experience with carbaryl—spraying plants on his family’s potato fields in rural upstate New York.

Relyea is not an alarmist, even though his studies have focused on the same pesticide that dusted his body as a child, that today’s standard for testing pesticide toxicity may, in fact, be all wrong, that the environmental impact from some of the world’s most popular pesticides may wind up being far greater than previously thought.

What concerns Relyea right now is that more testing is needed, that the understanding of nature gained through the tadpole experiments is little more than a keyhole view of a vast room. “We just don’t have enough information,” he says. “We’re just trying to figure out what happens in nature.”

—Kris B. Mamula is a senior editor of this magazine.


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