GAINESVILLE --- Reproductive and hormonal problems documented in alligators living in a polluted Florida lake have turned up in alligators living in other Florida lakes thought to be more insulated from pollutants, say researchers at the University of Florida.
"These long-term studies are the answer to finding out how environments change over time, naturally and under man's hand. This should be a wake-up call. We have to make sure that similar problems are not occurring in ourselves," said UF Professor of Zoology Lou Guillette.
A research team led by Guillette made headlines in 1993 when they said pesticides could be responsible for sexual deformities and a previous population decline of alligators in Lake Apopka near Orlando.
That lake suffered from a severe pesticide spill in 1980 and commercial development on its shores.
"Everyone accepted the fact that Lake Apopka had a problem," Guillette said. "We now have the same problems on another lake."
Preliminary tests on Lake Okeechobee, Florida's biggest lake, showed the research team many of the same problems it had seen before: lower testosterone levels and small penis size in male alligators. In addition, tests also showed a new problem: altered thyroid hormone levels. The results are scheduled to appear in the Feb. 17 issue of the scientific journal Environmental Toxicology and Chemistry.
Also during the studies, researchers for the first time found possible effects of environmental toxicants on the thyroid, a critical regulator of growth in animals.
Biology Professor Drew Crain, a former student of Guillette now teaching at the University of Mississippi, said the study shows that problems found in Lake Apopka alligators are confined neither to that lake nor to one system in the animals.
"Previous studies have focused on the hormones associated with reproduction -- the steroid hormones testosterone and estradiol -- but now we have evidence of disruption in other endocrine
Contact: Louis Guillette
University of Florida