New water sampling in the Rio Grande Valley’s irrigation ditches has found traces of pharmaceuticals, and the activist group that made the discovery called Thursday for more careful water monitoring to ensure it is not a threat.

Contaminants found include caffeine and acetaminophen (an over-the-counter pain reliever) as well as meprobamate, a tranquilizer. The most likely source is human waste, either from outflow from upstream sewage treatment plants for septic system.

The levels discovered were tiny, and the group unveiling the numbers said there is no evidence at this point that they pose a health threat.

“We’re not trying to scare people,” said Michael Jensen of Amigos Bravos during a news conference Thursday morning near Albuquerque’s new Rio Grande drinking water intake. “That’s the last thing we want to do.”

The irrigation ditches parallel the river, carrying water to farmers’ fields and then taking drainage water back to the Rio Grande. Jensen contends that the trace contaminants found in the irrigation ditches are likely to also exist in the river. Now that the Albuquerque metro area is treating and drinking that water, Jensen argued that more careful testing is needed to ensure contaminants are not making it into city taps.

Other data, including sampling by the U.S. Geological Survey, the New Mexico Environment Department and University of New Mexico researchers, shows that pharmaceuticals in the Rio Grande is less of a problem than in most U.S. rivers, said Kerry Howe, a UNM water quality expert.

Howe, who conducted an independent review of the city’s  said the technology used in the new Albuquerque Bernalillo County Water Utility Authority treatment plant is best treatment available for the vast majority of pharmaceuticals that might be encountered.

There are no studies showing human health effects from pharmaceuticals at the levels being detected, Howe noted. Jensen agreed, but said that long term risks nevertheless cannot be ruled out.

Further reading: Kerry Howe's report on Albuquerque drinking watet treatment (discussion of pharmaceuticals on page 17)