A comprehensive survey of the drinking water for more than 28 million Americans has detected the widespread but low-level presence of pharmaceuticals and hormonally active chemicals.
Little was known about people's exposure to such compounds from drinking water, so Shane Snyder and colleagues at the Southern Nevada Water Authority in Las Vegas screened tap water from 19 US water utilities for 51 different compounds. The surveys were carried out between 2006 and 2007.
The 11 most frequently detected compounds - all found at extremely low
concentrations - were:
• Atenolol, a beta-blocker used to treat cardiovascular disease
• Atrazine, an organic herbicide banned in the European Union, but still used in the US, which has been implicated in the decline of fish stocks and in changes in animal behaviour
• Carbamazepine, a mood-stabilising drug used to treat bipolar disorder, amongst other things
• Estrone, an oestrogen hormone secreted by the ovaries and blamed for causing gender-bending changes in fish
• Gemfibrozil, an anti-cholesterol drug
• Meprobamate, a tranquiliser widely used in psychiatric treatment
• Naproxen, a painkiller and anti-inflammatory linked to increases in asthma incidence
• Phenytoin, an anticonvulsant that has been used to treat epilepsy
• Sulfamethoxazole, an antibiotic used against the Streptococcus bacteria, which is responsible for tonsillitis and other diseases
• TCEP, a reducing agent used in molecular biology
• Trimethoprim, another antibiotic
The concentrations of pharmaceuticals in drinking water were millions of times lower than in a medical dose, and Snyder emphasises that they pose no public health threat. He cautions, though, that "if a person has a unique health condition, or is concerned about particular contaminants in public water systems, I strongly recommend they consult their physician".