14 DAY TRIAL // We know that contamination has the most harmful effects for the health of people and animals.
But sometimes, these harmful effects are some of the most bizarre: chemicals can turn a boy in a girl.
High levels of hormone-disrupting chemicals found in several spots along the Potomac River Basin were correlated with high amounts of the same chemicals in the blood of male fish that exposed female sex traits.
The compounds came from pesticides, flame retardants, perfumes, cologne and antibacterial hand washing soap.
A 2003 research discovered that the testes of male smallmouth bass (image) from the same area were producing eggs!
These contaminants, named endocrine disrupter compounds (EDCs), interfere with the fishes' endocrine system, because they mimic sex hormones, which regulate the development of sexual and reproductive traits of the organisms. "We're finding some of the compounds that are either are known or suspected endocrine disrupter compounds widely in the environment," said Douglas Chambers, a USGS scientist and lead researcher of the study.
"We're seeing them both in places where we see intersex fish and where we have not found intersex fish. Some of the compounds are nearly ubiquitous in the environment."
"However, scientists have yet to establish a definitive link between EDCs and intersex characteristics in fish," Chambers said.
"Part of the missing picture right now is we don't have all of the age data for the fish which is an important determination of length of exposure to some of these compounds," he explained.
Traces of many known or suspected EDC's were discovered in the fishes' blood; the compounds were detected not only in the river's water, but also in water from many sources, including fish hatcheries, poultry-processing plants and city water runoffs.
For the moment, it is not known if EDC's represent any direct threat to humans. "There's not any clear evidence at this moment," said Chambers. "We're seeing yearly worldwide reports about declines in human male sperm counts and some other sorts of indicators, but whether there is a linkage between the compounds and these effects is just unknown at this time."
Emergence of the intersex phenomenon was also signaled in aquatic species, like alligators, frogs and polar bears, from other US locations and Europe. That's because water concentrates the pollutants.