The Associated Press has another following up on yesterday’s investigative report about pharmaceuticals found in drinking-water supplies. They delve into the issue of who’s studying water supplies, and whether they’re revealing their findings. Accompanying the article is an alphabetical list of cities, so you can see whether your area’s water has been tested, and whether traces of drugs have been found; here in Washington, DC, for instance, tests have turned up carbamazepine, caffeine, ibuprofen, monensin, naproxen and sulfamethoxazole.

It’s nice that AP is supplying this list, because water providers and researchers often stay silent about test results:

When water providers find pharmaceuticals in drinking water, they rarely tell the public. When researchers make the same discoveries, they usually don’t identify the cities involved.

There are plenty of reasons offered for the secrecy: concerns about national security, fears of panic, a feeling that the public will not understand — even confidentiality agreements.

Water providers are only required to tell people of a contaminant in their water if the contaminant is on an EPA list of substances regulated under the Safe Drinking Water Act – and, at the moment, that list doesn’t include any pharmaceuticals. EPA Assistant Administrator for Water Benjamin Grumbles told the AP that the agency encourages utilities to “share with their community information they find out about their source water,” but it seems that most cities are reluctant to do so. Several say they don’t release results out of concern of what the public reaction will be:

“That’s a really sensitive subject,” said Elaine Archibald, executive director of California Urban Water Agencies, an 11-member organization comprised of the largest water providers in California.

She said many customers “don’t know how to interpret the information. They hear something has been detected in source water and drinking water, and that’s cause for alarm — just because it’s there.” …

Initially balking at the AP’s request to provide test results, Philadelphia Water Department spokeswoman Laura Copeland said, “It would be irresponsible to communicate to the public about this issue, as doing so would only generate questions that scientific research has not yet answered. We don’t want to create the perception where people would be alarmed.” …

“It’s a hard topic to talk about without creating fear in the general public,” [Robert Renner of the American Water Works Association Research Foundation] said.

Some said those fears could lead to much larger problems than the actual contamination.

Doctors “don’t want people to be afraid to take their medicine because of environmental concerns,” said Virginia Cunningham, an environmental executive for drug maker GlaxoSmithKline PLC. …

I can sympathize with the officials who are worried about consumer overreaction; people have certainly been known to fixate on the attention-grabbing headline or sound bite (“drugs in your water!”), and miss the detailed explanation about how the levels of contamination are very low and not known to cause health problems. The problem is that once the information gets out (as is bound to happen), the story then becomes “officials covered up results of drugs-in-water tests.” Then residents may get suspicious of officials, and be less receptive to their explanations about why the drugs in the water aren’t cause for alarm.

The other rationale for not disclosing results is a little harder for me to understand:

Officials in Arlington, Texas, said pharmaceuticals had been detected in source water but wouldn’t say which ones or in what amounts, citing security concerns. Julie Hunt, director of water utilities, said to provide the public with information regarding “which, if any, pharmaceuticals or emerging compounds make it through the treatment process can assist someone who wishes to cause harm through the water supply.”

Mayor Robert Cluck later said a trace amount of one pharmaceutical had survived the treatment process and had been detected in drinking water. He declined to name the drug, saying identifying it could cause a terrorist to intentionally release more of it, causing significant harm to residents.

“I don’t want to take that chance,” Cluck said. “There is no public hazard and I don’t want to create one.”

Ron Rhodes, water treatment plant supervisor in Emporia, Kan., explained why he wouldn’t disclose whether his community’s source water or drinking water had been tested for pharmaceuticals. “Well, it’s because of 9/11. We want everybody to guess.”

How, Rhodes was asked, could it endanger anyone to know if Emporia’s water has been screened for traces of pharmaceutical compounds?

“We’re not putting out more information than we have to put out,” said Rhodes. “How about that?”

So, there aren’t enough dangerous substances already out there that could be introduced into any municipal water system and cause widespread harm? Or, would-be terrorists don’t know about these substances, and can’t spend 10 minutes Googling them, but will seize on the mention of trace amounts of pharmaceuticals in a particular water supply to construct an elaborate plan in which they introduce a substance that interacts with existing traces of drugs to cause some particularly scary chemical reaction?

The risk of info about trace amounts of drugs leading to an act of terrorism is probably far smaller than the risk from ingesting those trace amounts of drugs every day for a lifetime. Yet, ever since 9/11, officials seem to think that mentioning terrorism will get the off the hook for failing to disclose hazards to the public.