SUSAN MONTOYA BRYAN Associated Press Writer ALBUQUERQUE, N.M. (AP) — New Mexico's largest water utility announced a plan Tuesday aimed at educating the public and keeping pharmaceuticals out of one of the West's most important water ways, the Rio Grande. The announcement by the Albuquerque Bernalillo County Water Utility Authority follows a recent discovery in the Rio Grande of caffeine, which scientists often look for as a possible signal for the presence of other contaminants. An environmental group also reported earlier this summer that it found traces of pharmaceuticals in the Rio Grande Valley's irrigation system. Both the U.S. Geological Survey and the New Mexico Environment Department have tested the Rio Grande for pharmaceuticals and other organics at several locations in recent years. The studies by the Environment Department turned up only a minute amount of the antidepressant amitriptyline in a stretch of the river near Santa Fe. Starting this month, the water authority will start testing both raw and treated drinking water and wastewater to determine the amount of pharmaceuticals in the water and where in the system they occur, said John Stomp, water resources manager for the authority. As part of the new program, the authority also will educate Albuquerque-area residents on how to properly dispose of old and unwanted medications. Rather than flushing them down the drain, the authority wants residents to mix unwanted medications with water and cat litter in a disposable container, seal it and throw it out. Fliers will be included with monthly bills starting in October, and the authority is looking at putting up posters in pharmacies and pursuing legislation that would allow pharmaceutical take-back programs for New Mexico residents. While the water authority said there are no known human health effects from exposure to trace amounts of pharmaceutical residues in drinking water, it wants to be proactive. "It's our life line here and we are now using it for drinking water and we don't want it polluted downstream or here," said Alan Armijo, chairman of the Bernalillo County Commission and vice chair of the water authority. More than a half million people in Albuquerque are served by the water authority and depend on the Rio Grande for some of their drinking water, while Santa Fe and Las Cruces are building diversion systems to use river water in the future. El Paso, Laredo and other Texas cities also depend on the Rio Grande along with the countless farmers along the river valley. Nationwide, an Associated Press investigation found pharmaceutical traces in drinking water supplies of at least 51 million Americans and in many waterways. The drugs ranged from antibiotics to psychiatric drugs to endocrine-disrupting sex hormones. The biggest source of pharmaceutical residue in the water is from human excretion, but manufacturers, health care facilities and residents also send unused drugs down the drain and into rivers and streams. Of the new effort to test the Rio Grande water, Stomp said measurements will be taken in parts per trillion. That's equivalent to about one-twentieth of a drop of water diluted into a 2-meter-deep Olympic-sized swimming pool. While drug companies, water providers and some scientists downplay any danger to ingesting pharmaceuticals at such low levels, other scientists believe that even tiny amounts — because drugs are designed to impact the human body — may cause harm over decades, especially in combination with other drugs. Scientific studies indicate that some drugs, including sex hormones and psychiatric drugs, can harm aquatic species. A smaller, emerging body of research suggests that tiny concentrations of some drugs can interfere with functions of human cells. The water authority also will participate in a yearlong study by the American Water Works Association Water Research Foundation to evaluate the effectiveness of specific filter techniques to remove pharmaceuticals from water. "It's just to step up our efforts and figure out what we can do," Stomp said. Michael Jensen of Amigos Bravos, the group that discovered trace pharmaceuticals in the valley's irrigation ditches, said the water authority's efforts are a "first step in the right direction." Jensen said it's hard to get a handle on the pharmaceutical issue because the science around it is just starting to come together, but he added that it's clear from numerous studies that there are impacts to aquatic life from even small amounts of pharmaceuticals and caffeine. "The big question is what's the impact on human health. That's what people are worried about," he said. Jensen said Amigos Bravos is pleased that the water authority is trying to get ahead of the curve by educating residents and considering take-back programs. Armijo said the problem of pharmaceuticals in New Mexico's waterways is not as bad as in other states and he wants to keep it that way. "If you don't start being proactive about it, when you do have a problem then your spending millions and millions of dollars to clean up the water," he said. "... We don't want it to get critical."