Macho Waters
Some river pollution spawns body-altering steroids
Janet Raloff / Science News v.159, n.1, 6jan01
On the way back from a field trip to one of Alabama's barrier islands in the late 1970s, W. Mike Howell and the students in his vertebrate biology class detoured over the state line into Florida to collect some fish.
En route to Pensacola, they passed a shady stream, Elevenmile Creek. It was a searing hot day, so it seemed like a good idea to stop and cool off. The consequences of that detour continue to expand.
"Pulling off the interstate," Howell remembers, "we didn't have any earthly idea that this creek was polluted." But as the students climbed down its banks, the smell of chemicals hit them. "The water was dark," he notes, "but we assumed it was just due to the tannins and resins that you see in many swampy southern streams."
An ichthyologist at Samford University in Birmingham, Howell had been studying the genetics of mosquitofish (Gambusia holbrooki). During the Florida rest stop, he and a graduate student started to look for mosquitofish specimens in the creek's murky shallows.
With each dip of their nets, they harvested a generous haul of the roughly 2-inch-long fish. It didn't take long to realize that something was strange. Every mosquitofish looked to be a male, which the scientists recognized by its gonopodium--a thin, elongated anal fin that males use for copulation.
As Howell and his student began speculating where the females could be, the pair realized that one of the males looked pregnant. On its side, it even bore the black spot signaling pregnancy.
"This suggested many of the others might also be females," Howell recalls. Further investigation confirmed that suspicion and launched the scientist on a 23-year hunt to find out what had so convincingly masculinized the physique of every female mosquitofish in this stretch of the creek.
The answer came from investigations of the Fenholloway River, an even more polluted stream 225 miles from Elevenmile Creek. Outside Perry, just east of Florida's panhandle, the southern Fenholloway bears the same reek and coffee-colored stain that Howell's team had encountered at the creek. In both cases, the water's aromatic pollution traced to wastes from nearby pulp-and-paper mills. Read more...
Hats off to GirlieGirlArmy for the tip!
Jessie S. says:
One of the nations biggest problems has yet to be discovered and this is all those medicines that we humans are peeing and pooping into the sewer systems. The endocrine disruptors coming off the nearly 80% unused portion of medicines we take are now being sprayed in forest lands clearly destroying the terristrial planet, running down stream to places like Puget Sound in WA. Even though they outlawed the dumping of sewage into the sound , it is now effecting the places where they nonw spray these waste products..
This is a growing hugh issue and rarely do I talk to anyone even aware of this problem. Stop medicating and adding to this relatively unknown destroyer