People like Steve, with such severe intolerance to tap water, are rare, but they are like the 'canaries in the coalmine', exposing the hidden dangers of things in
the environment that most of us would otherwise be unaware of-just like the 'electrosensitives' who first alerted us to the dangers of WiFi and mobile phones. So what's in drinking water that's so harmful to health? Clearly, the bad old days of people dropping like flies from sewage-infected water as a source of cholera and typhoid are long gone. Indeed, a major public-health revolution
resulted from the simple discovery that adding chlorine to municipal water supplies could eradicate those deadly pathogens. The irony is that such 20th-century 'progress' has since created many more water-borne hazards than the original faecal pathogens. Worse, chlorination itself is part of the problem.
Chlorine reacts chemically with organic particles in fresh water, harmless naturally occurring 'humic substances' that become toxic in the presence of chlorine. The water industry has known about them for decades, but downplays their importance, dismissing them as 'disinfection byproducts' (DBPs). Since their discovery in 1974, DBPs have consistently been considered harmless, but by the year 2000, a staggering 600 BDPs had been detected in tap water, falling mainly into two classes of chemicals: trihalomethanes (THMs) and haloacetic acids (HAAs). Some of these were already known as potential toxins. Faced with such an unexpected source of water pollution, our governments decided to set limits on THMs (but not HAAs). But because they're very difficult-and therefore expensive-to eradicate totally, levels are set to so-called 'realistic standards'. DBPs and birth defects This cosy complacency was dealt a hammer blow some 25 years ago when researchers decided to test tap water constituents on animals, especially foetuses. Experiments using trichloroacetic acid (an HAA) in rats showed it was "developmentally toxic", causing
a range of defects such as low birth weights and "soft tissue malformations" like 'holes in the heart' (ventricular septal defects, or VSDs). 1 To date, some three-dozen studies involving over
a million pregnant women all over the world have measured intakes of tap water (and so DBPs) and compared those levels to the health outcomes of their offspring. The results have revealed a litany of serious birth defects linked to tap-water intakes during pregnancy-with more than twice the normal risk of birth defects.
In France, there was evidence of "foetal growth restriction", in Lithuania of "congenital heart and musculoskeletal anomalies", and "neural tube defects" in Canada and in a review of five studies by Johns Hopkins University. 2 The most dramatic discovery was in a five- year Norwegian survey of nearly 286,000 births, which found an 81 per cent increase in the risk of VSDs. 3 These
same defects, plus others, also showed up in a pooled analysis of more than 396,000 births in Taiwan. 4 These serious effects weren't the result of faulty water
purification-the mothers had drunk tap water officially considered wholesome. When water companies have exceeded the permitted limits, as happened in New Jersey, there were increased
incidences of "reduced birth weight . . . nervous system defects, oral cleft defects, and major cardiac defects". 5 Sometimes foetuses even die due to tap water toxins. Consistent evidence of a 10 per cent extra risk of stillbirth was found in the above-mentioned Taiwan analysis. 6 The teratogenic (birth-defect-causing) effects of tap
water have been known for at least a decade, so why have doctors said nothing? The answer, at least in the UK, is that the authorities nail their colours to any contradictory evidence possible. When a major nationwide British study compared water companies' regional DBP records against the number of birth defects in the same areas, the researchers claimed there was "little evidence" of a link between DBPs and birth defects, 7 a verdict the UK authorities accepted at face value. But the study's small print tells a different story: there was a 45 per cent increase in VSD risk, and smaller increased risks for "major cardiovascular defects" and "gastroschisis" (extrusion of intestines through the abdominal wall). Although these findings were statistically significant, they were dismissed as "chance results", possibly because the study had been commissioned by the UK authorities themselves, whose interests would hardly have been served by
acknowledging the dangers of the nation's tap water. Yet, in a later paper (not funded by UK authorities), epidemiologist Mark Nieuwenhuijsen, based in Barcelona, admitted that the VSD evidence, albeit based on the pooled analysis of three studies, was strong enough that it "should be followed up". 8 So far, foetal heart problems have shown up in more than half the studies of mothers exposed to DBPs in drinking water, yet women planning a pregnancy are still being officially assured that mains water holds no dangers whatsoever. 9 DBPs and cancer
The health dangers of DBPs don't stop at birth; a lifetime of drinking tap water might even give you cancer. A pooled analysis of three European studies revealed a 47 per cent extra risk of developing bladder cancer. 10 Crucially, the extra risk correlated strongly with the amount of DBPs in the water-in other words, it was a significant dose-response relationship, considered
evidence of a direct causal effect. There also seems to be a direct connection between DBPs and colon/colorectal cancer, with a pooled analysis of 13 studies showing a 30 per cent extra risk from tap water. In this case, the longer the exposure to tap water, the greater the cancer risk-and this even with a relatively small mean DBP change of 35 mcg/L. 11
How can such tiny quantities be so carcinogenic? The answer has come from experiments on cell cultures, small animals and fish, which show compelling evidence of DNA damage. 12 One Greek study revealed raised levels of "micronuclei" in lymphocytes-"a well-established biomarker of DNA damage . . . associated with an increased risk of cancer"-despite Greece's exceptionally
low DBP levels, which are 1/50th of the maximum permitted in the UK and US. 13 Dr Rolaf van Leeuwen, of the World Health Organization (WHO) Dutch regional office, suggests
that our 21st-century challenge is "how to rid drinking water of potentially dangerous microorganisms and chemicals without introducing new hazards that might
pose new and different threats to human health". 14 Drug and chemical pollution One set of waterborne hazards the Victorians didn't have to face are the fallouts from 20th-century 'advances' in
agriculture and health-pesticides and pharmaceuticals.
While pesticides should be reduced to very low levels by microfiltration, drug residues are more of a problem. In 2004, the US government's Geological Survey (USGS) discovered that seemingly pristine river waters contained "prescription and non-prescription drugs and their metabolites, fragrance compounds, flame retardants and plasticizers, cosmetic compounds,
disinfectants, detergent metabolites, and plant and animal steroids"-entirely the result of legally deposited effluents from "intense urbanization and livestock production" upstream. 15 Downstream, that same water could be used for drinking. An investigation by the Associated Press in 2008 found that America's tap water is chock-full of
drug residues. Philadelphia's water contained 56 pharmaceuticals, including pain relievers, antibiotics, statins, antidepressants, heart and asthma drugs, and antiepileptics. Southern Californians are exposed to epileptic and anti-anxiety medications, while Washington DC residents routinely consume six pharmaceuticals with their water. In total, 24 US cities had
drugs in their tap water. 16 The water industry responded by pointing to studies showing that levels of drug residues are too low to affect people. 17 In 2005, a panel of eight experts formally
declared that drugs in drinking water constitute "no appreciable human health risk". Six of the eight were senior employees of major US drug companies. 18
But as the USGS researchers pointed out, "Little is known about potential human-health effects associated with chronic exposure to trace levels of multiple drugs through routes such as drinking water. Furthermore, drinking water safety criteria currently are based on the toxicity of individual compounds and not combinations of compounds."
A 2014 WHO information sheet agrees, admitting to "knowledge gaps" about the health risks of long-term low-level exposure to drugs and drug combos. 19 Water quality How do drugs get into tap water in the first place?
One way is by people flushing them down the toilet. Astonishingly, until recently this was the officially recommended way to dispose of medications-even in hospitals. But the greatest source of most water-borne drugs is human waste. As medications aren't completely used in the body, they end up being excreted in either their original form or as metabolites. These enter the sewage
system, where they're treated and then often recycled back to the watersheds. Although the entire process may seem distasteful, that's how most urban dwellers get their drinking
water. In some parts of London, tap water has already gone through five rounds of recycling. 20 In 2007, the Drinking Water Inspectorate (DWI), the official guardian of Britain's tap water, was sufficiently concerned about drug residues to commission a special study of tap water from four major urban sites. They detected traces of three pharmaceuticals: the epilepsy
drug carbamazepine, and painkillers ibuprofen and naproxen. 21 But the study was never followed-up, despite the report admitting "very limited data" about the drugs in tap water
nationwide. Yet, last August the DWI confidently declared that "levels of these pharmaceuticals . . . in drinking water are not anticipated to pose an appreciable risk to public health".
Such complacency sits rather oddly in the light of strong evidence of birth defects. Some British experts, like ecotoxicologist professor John Sumpter at Brunel University, have been warning for years against "the exposure of the pregnant mother, or more specifically her foetus, to these drugs via drinking water". 22 Water-quality expert Dr Andrew Johnson, of the
Natural Environment Research Council (NERC), agrees: "In the foetus, which is rapidly growing and comparatively tiny, the dose would be relatively higher
and any damage to its cells could be far more serious," he says. "There is no evidence to show that drinking-water treatment removes all these drugs, so while we are not
wanting to alarm people, it would be foolish to assume there is no risk."
What's more, the DWI seems to have ignored recent evidence that drugs add significantly to levels of DBPs because they also react with chlorine. The common pain-reliever paracetamol (acetaminophen) forms at least 11 new products with chlorine, two of which are "unequivocally" toxic. 23 Two technologies first introduced to remove pesticides also seem able to rid water of drugs. Granular activated carbon and ozonation, employed in tandem, are said to remove 100 per cent of contaminants-although, say environmental scientists at Imperial College, London,
this isn't true for all compounds. 24 German scientists have found the cholesterol drug clofibric acid impossible to remove. 25 Part of the problem is the lack of regulations for drug
contaminants-unlike bacteria and pesticides, for which there are specific limits allowed in drinking water. In most countries, drug contaminants come under the catch-all
requirement stipulating that drinking water should not be a health hazard. In Britain, this means that water companies have carte blanche to decide for themselves what's safe, and it was
only recently that the DWI first drew water companies' attention to drug residues in tap water. But even today, it seems to be the water companies' own judgement call as to whether to supplement chlorination with more advanced water treatments.
As usual, it comes down to money. Granular activated carbon and ozonation are too expensive to use routinely, and some water companies just don't have the equipment. Beyond chlorination
This means the state of drinking water is still reliant on 100-year-old chlorination technology, which generally works against bacteria, viruses and parasites-but for one major exception, the human gut parasite Cryptosporidium. Difficult to eradicate, it's been responsible for regular outbreaks of waterborne poisoning, sometimes causing fatal diarrhoea. Cryptosporidium is particularly hazardous for those with poor immunity, including the elderly and AIDS patients. While water authorities tend to blame inadequate treatment-plant maintenance, fatal outbreaks have occurred in the US despite state-of-the-art equipment, 26 while the DWI says the UK had two large water-related outbreaks in 2005.
Alternatives to chlorination have been developed- in particular, treatments using chlorine dioxide and chloramines-but these have only created new classes of DBPs that are sometimes even more genotoxic than the current ones, says the US Environmental Protection Agency (EPA). 27 Treating water with chlorine dioxide produces two major byproducts, chlorate and chlorite. A three-year
tudy of births in one Italian region discovered that the "fairly high" levels of chlorate and chlorite in mothers' drinking water led to a massive increase in birth defects: over three times more cases of kidney defects, nearly seven times more "abdominal wall defects", over four times more "cleft palate", nearly three times more "obstructive urinary defects" and nearly five times more
spina bifida. 28 "This is the first study showing an excess risk of different congenital anomalies related to chlorite and chlorate exposure via drinking water," say the researchers. "Further research is needed to confirm the observed relationships in larger datasets." There have been no further studies to date, and no established safety limits for chlorates and chlorites.
The DWI recommends that water companies merely "maintain THM and HAA concentrations below the guideline values [which] will provide adequate control over other chlorination byproducts". 29 But in the Italian study above, the water supply had THM levels that were "very low", so DBPs clearly don't march in step with each other.
The crisis to come
Water treatment technology is in crisis: its scientific research base is inadequate and its current methods primitive, with every advance creating its own set of poisons. In 2000, over 600 DBPs had been created; today's figure is probably double that-and no one knows what effects they're having on our health. Once again, though, our coalmine 'canaries' suggest an answer.
The last 30 years have seen a huge rise in allergies and intolerances to foods and environmental chemicals, and one recent study suggests they may be linked to DBPs. 30
US researchers found that people with raised levels of dichlorophenol have a higher incidence of allergies. In addition to being a pesticide metabolite, this chemical is
also a byproduct of chlorination, and was chosen because it's a DBP readily excreted in urine and a good indicator of the rest of tap water's byproducts. Allergies are thought to be the result of toxic overload of the immune system. The sensitive canaries have been hit first, but the rest of us should take heed. As for the water authorities, the science of water treatment is clearly
far too complex to allow them to continue with their 'fingers-crossed' approach to national health.
This is not the obvious solution it appears to be. Water safety regulations for these products are even more lax than for tap water. Some brands have proved to contain poisons like arsenic and phthalates-and even bacteria. Also, most water bottles are plastic (polycarbonate) and leach a variety of hazardous chemicals into the water-in particular, the hormone-disrupting bisphenol A (BPA). 1 RefeRences
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