A recent test of drinking water supplies revealed that a minimum of 41 million Americans are being exposed to antibiotics, anti-convulsants, mood stabilizers and sex hormones when they heads to taps to quench thirst. The drug levels aren't high  - in fact they're far lower than a regular dose would be - but though utilities insist the water poses no risk, scientists are expressing concern about the long-term health implications.

The Associated Press has conducted a five-month investigation and found affected water supplies in Southern California, Michigan and Kentucky, with a total of 24 major metropolitan areas. The explanation provided for the presence of the drugs found in tap water is that the medications individuals take that is not absorbed by the body "passes through" and flushed down the toilet. The water is released to lakes and reservoirs after being treated and is sometimes cleansed again at water treatment plants before being used by the public. Unfortunately all of these treatments do not completely eliminate drug residue.

The news gets even better: there are no federal requirements in place for the testing of drugs in water and less than half of the water providers contacted tested their supply, making the problem likely far more widespread than the current results  have indicated. Additionally, some water suppliers test for only a couple of pharmaceuticals meaning there is the potential for countless other unknown drugs that could be contained in the water. Drinkers of bottled or filtered water aren't immune to the problem either. Many companies who sell bottled water are just providing tap water with a fancy, impressive-sounding label.

The arguments over these findings continue with one side claiming the "drinking water continues to meet all federal and state regulations," while the experts on the other side claim "there is genuine concern that these compounds, in the small concentrations that they're at, could be causing impacts to human health or to aquatic organisms."

It's difficult to decide which aspect of the study is most disturbing: the fact that consumers have unknowingly been ingesting who knows what drugs for heaven knows how long or the knowledge that no water - filtered, bottled or otherwise - is immune to the problem.

» CNN Health