Auburn, Jan. 16---Day in and day out, we use a seemingly infinite variety of chemicals to whiten our teeth, lighten our hair and stave off infectious diseases.

Chemicals, after all, are a staple commodity in 21^st century America – a fact increasingly reflected in the nation’s wastewater supply.

A survey conducted several years ago by the U.S. Geological Survey reveals that several new classes of chemical contaminants are showing up the in flesh of fish below wastewater treatment plants. Similar findings have turned up in Europe.

Where are these chemicals coming from?

Perhaps the answer is best expressed in the old saying, "We have met the enemy, and he is us."

Humans, it seems, are the major culprit behind this trend, although concentrated animal feeding operations (CAFOs) and medical facilities also contribute.

"As far as humans are concerned, we wash many of these chemicals down our drains or toilets," says Dr. Jim Hairston, an Alabama Cooperative Extension System water quality scientist. "From there, many are passing through wastewater treatment plants into rivers, lakes and aquifers – many of which serve as public drinking water sources."

While it is true that treatment plants are equipped to remove most solid waste and many chemicals before wastewater is released into surface water, they are not equipped to remove all of them. And there lies the rub, Hairston says.

Among those chemicals not easily removed are antibiotics.

Since the discovery of sulfa drugs in the early 20^th century, antibiotics have played an indispensable role in medicine, saving the lives of millions. Still, there is a risk associated with the widespread use of antibiotics – one that is causing increasing concern among doctors and water quality scientists alike.

"Disease-causing bacteria continuously exposed to antibiotics increasingly develop resistance to them," Hairston says.

Within the past 50 years, Hairston says, a bacterium known as Pseudomonas aeruginosa has emerged as one of the "most opportunistic infections" to humans because of its ability to mutate rapidly and withstand antibiotic treatment.

This bacterium is sparking growing concerns among doctors and scientists alike, who fear that it will eventually become completely immune to all antibiotics – a problem that may be compounded even further by the trace residues of antibiotics that are increasingly showing up in drinking water, Hairston says.

Hormones, another class of chemical contaminants recently found in water, are also causing alarm.

More than 8 million women in the United States take a single estrogen replacement drug to treat the symptoms of menopause and osteoporosis, Hairston says, adding that male and female hormones are also used in feeds consumed by millions of livestock animals.

"Some scientists already suspect that estrogen and estrogen replacement drugs may be responsible for deformities occurring within the reproductive systems of fish," Hairston says. "And some of these reproductive abnormalities have been observed just downstream from numerous wastewater treatment plants."

At this point, scientists are not sure how severe the problem is.

In time, however, many suspect it may lead to a whole new approach to chemical use.

"If antibiotics and sex hormones are reaching surface and groundwater supplies at levels that cause real problems, we must be more vigilant in how we use pharmaceuticals and how we manage wastewater," Hairston says.

While all regions within the United States are at risk from these chemical residues, the semiarid West is of particular concern, he says. That is because many streams in this region rely almost exclusively on treatment plant effluent during dry seasons.

Moreover, many Western cities use wastewater to replenish aquifers that supply drinking water.