How safe is our tap water?

Have you ever wondered how safe is your tap water?

Researchers at the Southern Nevada Water Authority in Las Vegas screened tap water from 19 US water utilities for 51 different compounds between 2006 and 2007. Their comprehensive survey revealed that a large number of pharmacological agents can be found in tap water and some of these are hormonally active. The 11 most frequently detected compounds, albeit at very low concentrations (source: New Scientist) are:

• 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 use of pharmacological agents has increased in recent years and most of these compounds are excreted by the body through the urine and end up in our waste water. However, current techniques in waste water treatment seem to be not effective in taking out all the pharmacological agents from the water.

Researchers at the University of Montreal have recently detected the following drugs in the St. Lawrence River:

• bezafibrate, an anti-cholesterol drug
• enalapril, an anti-hypertensive drug
• methotrexate, a chemotherapy drug
• cyclophosphamide, also a chemotherapy drug

The waste water treatment plant in Montreal was able to take out the chemotherapeutic agents but not the cardiovascular drugs.

Increased contamination or improved detection?

The Nevada researchers are quick to point out that the concentrations of the 11 pharmaceuticals were very low, “millions of times lower than in a medical dose, and…that they pose no public health threat.” The concentrations were way below the set federal limits, at least for those with set limits. However, as in most pollution studies, it always ends up with the question whether the presence of these chemicals are due to increased contamination or improved detection. Or both.

Effect on the environment

The Canadian researchers are concerned about the effect of the compounds they detected on the flora and fauna of the St. Lawrence River. Hormonally active compounds can cause endocrine disruptions and have been observed to induce gender anomalies in fish and other aquatic organisms.

Effect on our health

Finally, we also have to ask as to what the long-terms effects of these pharmaceuticals are in our health. Are these compounds carcinogenic? Mutagenic? No data is available so far. Is it worthwhile to take all these chemicals out of the tap water?

According to Nevada researcher Shane Snyder

“the costs of “extreme purification” – far beyond what is needed for safety alone – are huge in terms of increased energy usage and carbon footprint. Ultra-pure water might not even be safe.”

According to a spokesperson from the US Environmental Protection Agency (EPA):

neither this nor other recent water assessments give cause for health concern. “But several point to the potential for risk – especially for the fetus and those with severely compromised health.”

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