Troubled by drugs discovered in European waters, poisons expert and biologist Francesco Pomati set up an experiment: He exposed developing human kidney cells to a mixture of 13 drugs at levels mimicking those found in Italian rivers.
There were drugs to fight high cholesterol, high blood pressure, seizures, depression, pain, infection and cancer, but all in tiny amounts.
The result: The pharmaceutical blend slowed cell growth by up to a third — suggesting that scant amounts might exert powerful effects, said Pomati, who works at the University of New South Wales in Sydney, Australia.
Taken alone, this was a modest study. But Pomati’s work is part of a body of emerging scientific studies that indicate that over time, humans could be harmed by ingesting drinking water contaminated with tiny amounts of pharmaceuticals.
In another recently published study, Pomati discovered that some of those pharmaceuticals could either amplify or reverse the effects of some others. And his work indicates that some drugs cause cellular effects at scant concentrations that — strangely — cannot be seen at higher levels.
Such findings are preliminary; they alone cannot demonstrate the same effects within the human body. But they provide scientific hints, just like cellular experiments that routinely guide discoveries of new drugs.
They also heighten worry about the possible effects on especially vulnerable groups, like the very young, old or sick.
“My wife is pregnant, and I don’t let my wife drink the water … where I know that there are pollutants like pharmaceuticals in concentrations that are detectable and in mixtures that are complex,” Pomati said.
Elsewhere in the world, other researchers are finding results similar to Pomati’s.
In research awaiting publication, human breast-cancer cells grew twice as fast when exposed to estrogens taken from catfish caught near untreated sewage overflows in Pennsylvania, compared with other fish.
The University of Pittsburgh researchers didn’t calculate how much effect came from pharmaceuticals instead of natural hormones, but their earlier work points to birth-control pills and hormone treatments as important contributors, said lead researcher Conrad Volz.
He said people who regularly drink water containing low levels of hormones may be at higher risk, since they would presumably consume more of these drugs than those who only occasionally eat such fish.
Scientists at the Helmholtz research center in Leipzig, Germany, linked low levels of the pain reliever diclofenac to an inflammatorylike response in human blood cells, according to biologist Kristin Schirmer.
Sandra Steingraber, a biologist at New York’s Ithaca College, said many efforts to see how trace drugs affect humans don’t fully consider the range of pharmaceuticals in the environment and whether someone has been exposed at susceptible times, such as childhood or old age.
Taking notice of accumulating evidence, the drug industry has backed studies of its own that have found very slight, if any, risk to humans.
But these studies haven’t used water samples analyzed for drugs. Then, there are the byproducts of the drugs. When medications are digested and processed through water-treatment plants, they may take a new metabolic form.