Pesticides harm frogs, scientist says

09/26/08 - Last night in the University of Rhode Island Memorial Union, Dr. Tyrone Hayes presented his knowledge of chemicals and how they are affecting the ecosystem, and ultimately mammals. Hayes is a biologist, herpetologist and is a professor at the University of California, Berkley. The lecture was the keynote speech of Diversity Week.

The mixtures of different chemicals have a great impact on the environment. More specifically, Hayes spoke of a chemical known as Atrazine.

Atrazine is an herbicide used with manufactured crops, and has been used in the environment for approximately 48 years. During that time, 80 million lbs. of this compound have been exposed to the environment. This deadly chemical has been outlawed in Europe, but not in the United States, Hayes said.

Hayes introduced the experiment he conducted with frogs and the various results of their exposure to the harmful chemical Atrazine.

"When you exposed frogs to Atrazine, it caused reproductive abnormalities," said Hayes.

Chemically speaking, Atrazine was turning into Armatose, which is an enzyme that converts into estrogen. In other words, the male frogs being used in the Hayes' experiment were becoming chemically castrated.

Hayes continued with his presentation by showing slides of male frogs acting as females, and even showed one mating with its brother.

Hayes also had results of the studies from North American Leopard frogs. The males were producing eggs in their testes rather than having sperm.

Five years ago there was a study in Wyoming; 92 percent of the frogs had abnormalities in the contaminated areas. Five years later the study was and the same area was no longer contaminated with Atrazine. In addition, there were no chemically castrated frogs found. According to Hayes and his studies, these frogs are more likely to be found in areas with Atrazine exposure.

Hayes explained the exposure to various chemicals have ecologically significant effects on metamorphosis. The frogs in his experiments were incapable of making immune cells and therefore were not able to fight off diseases, he said. This is true for every living being, not just frogs. The more pesticides the frogs come in contact with, the larger the stress hormone response is. However, the pesticides were not affecting the frogs directly.

"The animals have damaged organs that are supposed to get rid of pesticides," Hayes said. In other words, pesticides were causing deaths in various organisms.

But frogs were not the only animal affected. Rats were also having immune failure and neural damage. The testosterone level goes down, while the estrogen level increases in rats.

Hayes also spoke of the effect of pesticides on fertilization. When the rats produced males, they had prostate cancer, which would continue from generation to generation.

"The point is," Hayes said. "This can happen to humans."

The nation's drinking water is another issue Hayes said, he was concerned with. He conducted research on the Salinas River in California and noticed the increase in pesticides running upstream.

The top of the stream had extreme amounts of pesticides, which he concluded was from the significant amounts of agriculture surrounding the area.

"What we are finding in frogs is also relevant in human health," said Hayes.

Males with low sperm count have the same amount of Atrazine in their urine as the frogs Hayes uses in his studies. Hayes also researched that men develop prostate cancer more easily the longer they work in agriculture.

"If the manufacturer doesn't want me to do it, it must be the right thing to do," said Hayes.