This is a continuation of the look at the claims of Women's Health Magazine article "What's in your tap water?"
In yesterday's post, I looked at two "nasties" that might end up in your tap water: chlorination by-products and bacteria. Both are related to the disinfection (or failure of disinfection) of drinking water by public water suppliers.
The two other pollutants listed in the Women's Health article are lead and pharmaceuticals, which I'll look at in a bit more detail below.
Lead is definitely nasty. There is no question that exposure lead is dangerous, particularly for children:
The main target for lead toxicity is the nervous system, both in adults and children. Long-term exposure of adults can result in decreased performance in some tests that measure functions of the nervous system. It may also cause weakness in fingers, wrists, or ankles. Lead exposure also causes small increases in blood pressure, particularly in middle-aged and older people and can cause anemia. Exposure to high lead levels can severely damage the brain and kidneys in adults or children and ultimately cause death. In pregnant women, high levels of exposure to lead may cause miscarriage.
So definitely bad.
The source of lead contamination in drinking water is usually corrosion of household lead pipes. Lead plumbing is nothing new. More than two thousand years ago, the fountains and baths of Rome were supplied with water traveling through lead pipes. Fortunately for the Romans, their water contained enough calcium that a crust of limestone formed inside the pipes, preventing lead from leaching into their water supply.1
Over the centuries other communities have not been as lucky. For example, it's estimated that in the early 20th century the use of lead pipes - particularly new lead pipes that didn't have any mineral encrustations on the inside - increased stillbirth and infant mortality rates as much as 50 percent in some Massachusetts towns.
It's only relatively recently that public health measures have targeted lead plumbing. In 1986 the U.S. Safe Drinking Water Act was amended to require "lead free" pipes. While that reduces the risk of lead contamination from the pipes in homes built after 1986, it does not mean that recently-built plumbing systems are necessarily lead free. The EPA warns:
However, new homes are also at risk: even legally “lead-free” plumbing may contain up to 8 percent lead. The most common problem is with brass or chrome-plated brass faucets and fixtures2 which can leach significant amounts of lead into the water, especially hot water.
As scary as that sounds, the primary sources of lead exposure, at least for children, are lead-based paint and lead-contaminated dust. Drinking water only accounted for an estimated 10-20 percent of total lead exposure in the general population in 1991. I'd hope that in the 20 years since then the wider use of lead-free (or "lead-free") plumbing has reduced that amount.
But even if you have lead plumbing at home, Women's Health suggests you can minimize the risk of lead contamination in your tap water.
Lead can seep into water that's been sitting stagnant in pipes, "so run your tap for two minutes to flush it out," says James M. Symons, M.D., author of Plain Talk About Drinking Water. (Rather than waste that water, use it to wash your hands or the dishes.)
Or maybe fill a pitcher with drinking water after washing the dishes. No waste at all that way!
In 2008 the Associated Press investigated whether traces of pharmaceuticals could be found in treated drinking water. What they found looked like a serious problem:
At least one pharmaceutical was detected in tests of treated drinking water supplies for 24 major metropolitan areas, according to an Associated Press survey of 62 major water providers and data obtained from independent researchers.
The source of the pollution is us, as it is cutesily explained in Women's Health:
Every time you pop a pill—whether it's a Tylenol or Xanax— traces of it come out in your pee. And (ick alert!) that urine can eventually find its way back into our tap water.
But its not at all clear what the health risk - if any - the presence of pharmaceuticals presents. The type of chemical contaminants the AP investigation found varied widely from location to location; from acetaminophen, caffeine and cotinine in Atlanta (Tylenol, coffee and cigarettes?) to meprobamate and phenytoin in Los Angeles (anti-anxiety and anticonvulsant meds).
As a recent conference report points out, the concentrations of the pharmaceuticals and drug by-products is quite low:
The primary exposure pathways [of pharmaceuticals] to humans other than those from prescribed dosing are through drinking water at part-per-trillion levels (Stackelberg et al. 2007; Ye et al. 2007), which for typical daily consumption over a lifetime, would provide exposure to individual compounds well below a single therapeutic dose and suggest little threat to human health (Fent et al. 2006), although the effects on pregnant women and their fetuses are still not clear.
The EPA doesn't as yet regulate the levels of such compounds, and there currently isn't an easy way to reduce your possible exposure. The jury is still out on whether this is even something we should worry about health-wise. There's not much we can do but watch what the studies currently in progress turn up over the next few years.
I think a greater concern is the effect of pharmaceuticals and drug by-products on the environment. Wastewater from municipal sewage treatment plants has been shown to disrupt the endocrine systems of fish (causing feminization of male fish), and irrigation with reclaimed water can deposit pharmaceuticals in the soil. We likely won't understand the long-term effects until significant and possibly irreversible damage has been done.
Rodriguez-Mozaz S and Weinberg HS. Meeting Report: Pharmaceuticals in Water—An Interdisciplinary Approach to a Public Health Challenge. Environ Health Perspect. 118(7): 1016–1020. (2010) doi: 10.1289/ehp.0901532. (free full text)
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Bottom image: National Cancer Institute Visuals Online: Pictured is an array of prescription drugs. The pills are scattered and unarranged. In some photos is a container of birth control pills In the background.