VICKI BLAZER, U.S. Geological Survey: So here we have this large discolored area in the liver, and then you see all these little white spots. Here's another totally discolored area.
HEDRICK SMITH: And that's a signal of some bigger problem.
VICKI BLAZER: Yes, when we see a really high prevalence in a population, that indicates there's some problem going on in that water.
HEDRICK SMITH: [voice-over] And when Blazer dug deeper, she found a surprise.
VICKI BLAZER: One of the major and most interesting findings was intersex in the male bass. When we look at the male gonads, or testes, what we find is immature eggs within the male testes.
HEDRICK SMITH: [on camera] So you got a sort of feminization of male fish. Is that a big, alarming finding in marine biology, aquatic biology?
VICKI BLAZER: Yes, and that has certainly attracted a lot of concern and attention.
HEDRICK SMITH: [voice-over] Scientific studies have linked abnormal mutations in marine creatures, like intersex, to exposure to chemical compounds that mimic or imitate natural hormones in the body. These chemicals are called endocrine disrupters.
ROBERT LAWRENCE, M.D., Johns Hopkins School of Public Health: Endocrine disruptors are very, very potent chemicals at infinitesimally small quantification. I mean, you're talking about parts per million or parts per billion. They interrupt the normal way in which the body controls everything from growth and development to thyroid function to reproductive function to estrogen levels, testosterone levels. So they're very, very important, and they are of deep concern because there are so many of them now.
HEDRICK SMITH: There are thousands of these worrisome chemicals that have gotten into the environment, and one reason is that they're part of everything we do.
Dr. ROBERT LAWRENCE: The list of things that bring these organic pollutants into our bodies is a long list, and it ranges from home care products - soaps, toothpaste, cleaning agents in the household - to things we put on our lawns, the things that we use all the time- the plastic industry, the rubber industry, lubricants, fuels, the highways.
HEDRICK SMITH: [on camera] When you see scientists like Vicky Blazer cutting open fish, finding intersex in the male fish, seeing high levels of fish kills, seeing immune systems disrupted, seeing other damage to the fish, is that a warning to you, potentially, about human health?
Dr. ROBERT LAWRENCE: Oh, absolutely. The warning- not just from the smallmouth bass in the Potomac but from amphibians all across the country. You have frogs with six legs, hermaphroditic frogs, male frogs with ovaries, female frogs with male genitalia. These are the canaries, the modern canary in the mine that we haven't been paying enough attention to.
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PBS More on endocrine disruptors]
HEDRICK SMITH: [voice-over] So many new chemicals have emerged lately that scientists and regulators are playing catch-up to industry, trying to spot which chemicals they think pose new danger in our water.
VICKI BLAZER: EPA does not regulate any of these things yet. And in many cases, there isn't even the methods to measure them in the amounts that they actually have a biological effect.
HEDRICK SMITH: [on camera] So science and the regulators are behind the curve dealing with what industry and society is producing or wants.
VICKI BLAZER: Correct.
HEDRICK SMITH: [voice-over] Playing catch-up in regulating these new chemicals may be a problem for more than just these fish.
VICKI BLAZER: The endocrine system of fish is very similar to the endocrine system of humans. Fish have thyroid glands. They have the functional equivalent of adrenal glands. They pretty much have all the same hormone systems as humans, which, again, is why we use them as sort of indicator species.
