The amounts being found are infinitesimal - in parts per billion or trillion. A part per billion can be thought of as one grain of salt in a swimming pool, the U.S. Environmental Protection Agency says.
But studies on fish living in streams show that male and female fish can develop the other sex's proteins and organs when there are endocrine disrupters - from some flame retardants, birth control pills or steroids - in the water in parts per billion. What is unclear is the effect this has on humans, if any.
"We need to expand the task there," said Christian Daughton, who heads the environmental chemistry branch at the EPA's National Exposure Research Laboratory. "But the point is that no organism is exposed to one toxicant at a time. What's happening here involves multiple chemicals at a time, and naturally occurring toxic chemicals as well."
There were no studies being done on the health effects of chronic exposure to the compound cocktail, according to officials from the EPA, the Food and Drug Administration, and the Centers for Disease Control and Prevention. They say they need to figure out which chemicals are appearing, and where, before deciding what to focus on.
However, the American Water Works Research Association in Denver, which funded the nationwide drinking-water-plant survey, is conducting a two-year study on the health effects of the chemicals. Philadelphia is part of the study.
"We have two choices: We can sit around and do nothing, or we can take what we have - a basic understanding of the fundamental risks - and work with a team of toxicologists and find out where we would find effects and at what levels," said Shane Snyder, a project manager with the Southern Nevada Water Authority and head of the water works association's study. The study is expected to be completed in 2006.
One facet of the investigation looks not only at the drinking-water risk, but at how it compares with similar risks from other products - for example, additives in food and chemicals in the air.
"We have what we get from air, what we eat, from skin contact, and that's part of the question," Snyder said. "What is the realm of possible exposure."
Part of the problem is population growth. People drink and flush and wash, and the water has to go somewhere - and mostly it goes into the sewer system, into the wastewater treatment plant, and then into a river or stream. Drinking-water plants take up water from the rivers and streams, treat it, and send it into the taps.
In New Jersey, a U.S. Geological Survey released in August studied both the surface water and the finished drinking water at the plant in Passaic Valley, which disinfects with chlorine. The study looked for 106 different compounds. In each of the four samples, there were at least 11 contaminants. Several of the same contaminants turned up in all of them, including caffeine, nicotine, fragrance ingredients and Carbamazepine - a drug used to treat seizures.
The levels found were far, far below a daily dose. Assuming that most people drink about half a gallon of water a day, a lifetime intake of Carbamazepine would be 13 milligrams in 70 years, compared with a single therapeutic dose of 100 milligrams.
"The question is: What do we do about this now?" said Eileen Murphy, head of science research and technology for the New Jersey Department of Environmental Protection. The agency is starting a pilot program with two plants, including the one in Passaic, to try to remove the compounds, at a cost of $2 million. The plant is using ozone gas to break down the chemical compounds, a fairly simple process.
Pennsylvania has not started statewide water testing, officials said.
Many drinking-water officials say they do not specifically test for organic wastewater contaminants because the testing is expensive - about $1,000 per sample - and because there is no requirement by the EPA to do so.
"It's an issue that we're following in the literature," said Preston Luitweiler, vice president of water resources at Aqua Pennsylvania Inc., which oversees many wastewater and drinking-water plants in Bucks, Chester, Delaware and Montgomery Counties. "We do a lot of broad screening for things and we don't see these compounds at levels that would be a concern for us."
But Christopher Crockett, manager of watershed protection at the Philadelphia Water Department, is concerned.
"In our preliminary study, we found all the compounds the New Jersey study found, and we also found traces of potential endocrine disrupters," he said. The study was not available for release because the agency had just started testing, he said, but all the compounds were found at parts per trillion or less.
Part of the reason Philadelphia is checking out its water is because some of the city's water comes out of the Schuylkill - right below where the Wissahickon Creek meets the river. The creek travels from its headwaters in Montgomery Township down through Upper Gwynedd and Ambler.
The Wissahickon takes in the flow from five major wastewater treatment plants. The wastewater treatment plants also take in the flow from several industrial plants, including the Merck pharmaceutical plant in West Point. At times, the nonnatural water sources account for as much as 95 percent of the stream's flow.
In certain parts of the creek, more than 20 percent of the fish had disease, tumors or fin damage, according to a 2003 EPA study. The "very high level of disease and anomalies" was typical of water found downstream of pollution sources, the report said.
There have been no reports of "gender bending" fish in the Wissahickon. However, the township of Upper Gwynedd recently petitioned to downgrade the upper part of the creek. Currently, the creek is set at standards so that cold-water fish, such as trout, can live in it.
The change, which is under review, would designate the upper 12 miles as a "warm water" fishery, which might eventually allow for higher releases from the wastewater treatment plants and change the water-quality standards.
At a hearing in June, a Merck & Co. Inc. senior environmental engineer and a water consultant retained by Merck accompanied the township manager and attorney to support the petition.
Leonard Perrone, Upper Gwynedd township manager, said the issue is not about water quality, it's about accuracy. He said no trout inhabit the creek that high up, only downstream. Changing the designation would accurately reflect the upper stream's quality, he said, and have no effect on the creek.
"What's happening in the upper part of the creek doesn't necessarily affect the lower part," he said.
Merck officials said they became involved in the petition process because the township requested the studies the company had done on the waterway. Both Perrone and Merck said they would not ask to change their pollution permits in any way.
"Whatever the quality of the creek is now, it can't be less than that," said Rob Cavett, the Merck senior environmental engineer who attended the petition meeting.
Crockett said the Philadelphia Water Department would petition against the change.
"My family drinks water out of the Queen Lane plant, and I'm going to make sure it's as safe as possible," Crockett said. "It sounds scary, but is it dangerous? No. You get more caffeine from a cup of coffee.
"But do we want to remove everything we can, if we can? Yes."
Contact staff writer Dawn Fallik at 215-854-2795 or email@example.com.