Drinking Tap Water: How Safe Is It?

Research indicating insecticides and antibiotic resistant superbugs are finding their way into drinking water will heighten consumer fears

By David Noble

A recent Gallup poll revealed the concern Americans have about tap water pollution with over 63 percent stating they are worried “a great deal” about drinking polluted water. Water quality fears in a country where most people still believe they can drink out of the tap and not worry too much about getting sick are being stoked not only by events like Flint, but also by new scientific studies about emerging contaminants.

The Federal USGS science agency warns that research is “documenting with increasing frequency that many chemical and microbial constituents not historically considered as contaminants are present in the environment on a global scale.” Those contaminants encompass antibiotic-resistant bacteria that survive on beaches, on plant surfaces, and in the soil, as well as other pollution such as insecticides and pharmaceuticals.

A study earlier this year found insect-killing neonicotinoids had entered the human drinking water chain. According to the study, published in Environmental Science & Technology Letters, chemists and engineers from the U.S. Geological Survey, a federal agency, and the University of Iowa, identified the presence of three neonicotinoids in drinking water delivered from an Iowa City treatment facility.

Just two years after a U.S. Geological Survey discovered neonicotinoids in over half of water samples taken from streams throughout the United States, the Iowa University scientists detected clothianidin, imidacloprid, and thiamethoxam in tap water samples taken over a seven-week period. The researchers said traces of neonicotinoid chemicals remained despite treatment.

Neonicotinoids are a class of insecticides that have been used widely in America since the 1990s by farmers to fight crop-damaging bugs, but they have also been blamed for a rapid and alarming decline in honeybee populations. Engineered to be more environmentally friendly by causing less toxicity in birds and mammals than targeted insects, neonicotinoids have seen growing scientific consensus that the insecticides are causing significant environmental damage.

Apart from honeybees, the pesticide has been found in insects, microbes, and even coastal shellfish, prompting several European countries such as Germany, France, and Italy to restrict their use. In fact, there has been a moratorium on neonicotinoids use on flowering crops in the European Union since 2013.

But neonicotinoids are not the only emerging problem of concern. Late last year, researchers in France reported finding a drug-resistant “superbug” in drinking water for the first time in a developed country.

The study, appearing in the journal Antimicrobial Agents and Chemotherapy, a publication of the American Society for Microbiology, said the “findings highlight the possible human transfer of ESBL genes through drinking water in high-income countries.” ESBL’s are bacteria that produce an enzyme that can break down commonly used antibiotics, such as penicillin, and render them ineffective for treatment.

There are many more emerging threats to human health being found in drinking water, including pharmaceuticals, personal care products (PCPs), and endocrine disrupting chemicals (EDCs). PCPs can be shampoos, bug sprays, and sun screens, or antibiotics, heart or cancer medications, and livestock food additives, while EDCs range across substances like pesticides, herbicides, and synthetic hormones.

The issue is that the emerging contaminants are often non-volatile, water-soluble, and charged molecules. This means substances like pharmaceuticals can slip through treatment plants designed to remove traditional pollutants, a problem WHO say requires more advanced treatment processes, such as ozonation, advanced oxidation, activated carbon, and reverse osmosis.

The Centers for Disease Control and Prevention (CDC) says reverse osmosis systems can reduce the levels of common chemicals such as lead, volatile organic compounds, and germs in drinking water. This is important for those with immune systems weakened by chemotherapy, AIDS, or organ transplants, or indeed anyone with a keen interest in what they ingest, from expectant mothers to athletes.

The American Water Works Association (AWWA) writes reverse osmosis is excellent for removing the perfluorinated compounds (PFCs) used for industrial and consumer applications such as non-stick coatings and firefighting foams. PFCs have potential health implications for humans and wildlife and are persistent in the environment and highly soluble in water.

Achieving advanced water treatment processes able to tackle the newly emerging contaminants may take years. Until then, the best hope for anyone concerned about their tap water is probably to install a point-of-use RO system designed to remove large pharmaceutical molecules and other contaminants from drinking water before it comes out of the faucet.

David Noble is communications head at Bluewater, a global leader in water purification in the USA, Europe, and China. He may be reached at david.noble@bluewatergroup.com.

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