Women’s Health: What’s in Your Tap Water? (Part 3 of 3)

Sep 29 2010 Published by under Biology & Environment

This is a continuation of the look at the claims of Women's Health article "What's in your tap water?"

Put a cork in it?

In my previous posts, I took a look at the four pollutants that Women's Health highlighted as potential tap water pollutants: chlorination byproducts and bacteria and lead and pharmaceuticals. All are indeed possible tap water contaminants that have the potential to adversely affect your health.  But I think the way the article - really more of a short list - framed the information is really problematic.

Here is the intro:

Think that's clean water coming out of your faucet? Think again. New studies have found a host of nasties in tap water.

There's a lot wrong in that short paragraph: the "nasties" aren't new, the water that comes out of most faucets is clean, and, even if it wasn't, the article doesn't provide any information I could use to find out what's in my tap water.

First off, it's silly to suggest that the information is based on "new studies". The potential dangers of lead pipes has been known since the time of the Roman Empire. Treatments to kill bacteria and other pathogens have been in use  since the late 19th century, and chlorine was first added to water as a disinfectant a century ago. The potential risks associated with the ingestion of chlorination byproducts have been studied for more than 30 years. Over the years it has become less likely that the water you are drinking contains any of those pollutants.

The only fairly recent discovery is the presence of pharmaceuticals and drug by-products in the water supply. As yet there isn't any data demonstrating that these compounds are typically found at high enough levels in drinking water to be a health concern.

Some of you have probably noticed my use of weasel words: it's likely there are lower levels of chlorination byproducts in tap water than there were 30 years ago, and at typical levels the four pollutants aren't a significant health threat. That's because water quality can vary a lot from location to location.

The water coming out of my faucets has a different source and passes through a different treatment plant than the water provided to folks in the next town over. My water might even be different than what's coming from the tap of other homes in my neighborhood, since their plumbing might have a different amount of lead or corrosion.

So while the Women's Health article correctly points out the "nasties" exist, the information they provide can't help you assess the risk in drinking your tap water, and make the pollutants sound like a much bigger problem than they are.

So what is in your tap water?

I'd drink this.

If you are concerned - or curious - there are a couple of ways to find more information about your water.

The EPA requires suppliers that serve at least 100,000 people1 to send an annual water quality report to all customers . Most large water districts have their most recent report available online. See, for example, the reports for Metro Boston, St. Louis, and the East SF Bay Area.  The EPA also has links to other online reports and a database of reported violations of safety standards.

While the EPA-mandated reports can tell you what's in the water when it's distributed, it obviously can't take into account contaminants like lead that can come from the plumbing inside your home.  The only way to determine lead levels is to have your water tested in a laboratory.

Additional information:

EPA Information on home water testing (pdf)

EPA's safe drinking water Hotline (answers general questions about water safety)

EPA Local Drinking Water Information (find a report from your local water supplier)

EPA Safe Drinking Water Information System database (reports violations of EPA drinking water regulations)

USGS report on private well water safety and EPA Private Drinking Water Well information (well water is not part of the public water supply, and is not governed by EPA regulations)

1. I get an annual report from my local water supplier even though it only serves 40,000, and so is not required to mail out a report.  I assume that other smaller water districts do the same.

Is bottled water a good substitute for tap water?

Better bottled?

If an alien landed in Southern California, it might get the impression that drinking water only comes in plastic bottles. Ask around, and many people will tell you that they drink bottled water because it's "healthier" - or at least in some way "better" - than what comes from their faucet.

While bottled water may sometimes taste better, there isn't any evidence that it's any purer or healthier than tap water.  It can even contain the same pollutants, such as chlorination byproducts or bacteria.

That's not particularly surprising, since many of the brands of the bottled water that you find in your supermarket - like Pepsi's Aquafina and Coca-Cola's Dasani - are simply tap water that may (or may not) have gone through an extra round of purification.

To be fair, the Women's Health article doesn't suggest that we should buying bottled water. But since it strongly implies that "our" tap water is full of nasty pollutants, I wouldn't be surprised if some readers thought that was the unspoken take-home message.

Why is that a problem? Bottled water is much much more expensive than tap water and generates tons of plastic waste every year. It's bad for your wallet, bad for your environment and has no special health benefit.  I'm trying to break my own bottled water habit for that reason.

So what can you do?

If you are concerned about lead in your plumbing, the EPA suggests only drinking cold tap water, and, if the faucet has not been used for 6 or more hours, to let the water run briefly before filling up your glass.

You can also use a water pitcher with a carbon filter to remove minerals and other impurities. That has the added benefit of allowing the water to stand long enough for chlorination byproducts to evaporate.

And you can not worry too much - water straight from your tap is likely just fine.

Additional Reading

Lalumandier JA and Ayers LW. Fluoride and Bacterial Content of Bottled Water vs. Tap Water. Arch Fam Med. 9:246-250 (2000)     (free full text)

Bottled Water Regulation and the FDA.

National Academy of Sciences & Global Health and Education Foundation: Safe Drinking Water Is Essential


Be sure to check out all the Women's Health review posts.

7 responses so far

Women’s Health: What’s in your tap water? (Part 2 of 3)

Sep 28 2010 Published by under Biology & Environment

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.

Roman Lead Pipe

Nasty Lead

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!

Additional reading:

EPA: Lead in Drinking Water

EPA: Is There Lead in my Drinking Water?

Levin R. et al. Lead Exposures in U.S. Children, 2008: Implications for Prevention. Environ Health Perspect. 116(10): 1285–129 (2008). doi: 10.1289/ehp.11241. (free full text)

1. Unfortunately for the Romans they also used lead cooking vessels and added leaded compounds to their food, and causing widespread lead poisoning, particularly among the Roman elite.
2. A California law (pdf) that went into effect in January limits the amount of lead in the "wetted surfaces of pipes, pipe fittings, plumbing fittings and fixtures" to 0.25 percent. I wonder if there was a rush to purchase "traditional" brass and bronze fittings before the California law went into effect.

Prescription Drugs

Nasty Pharmaceuticals

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.

Additional reading:

USA Today: Drugs found in drinking water

FRONTLINE: poisoned waters: how safe's your drinking water?

FRONTLINE: teacher center: teacher guides by film: Poisoned Waters

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)

EPA: Pharmaceuticals and Personal Care Products as Pollutants

USGS: What's in Our Wastewaters and Where Does it Go?

- - -

Continued tomorrow: What's really in your water and is bottled water the solution?

Read all the Women's Health review posts.

Top image: Lead pipe to supply water to the Great Bath at Rome Roman Baths by Andrew Dunn on Wikimedia Commons.

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.

5 responses so far

Women's Health: What's in Your Tap Water? (Part 1 of 3)

Sep 27 2010 Published by under Biology & Environment

Water, water, water

At the suggestion of Scicurious, a bunch of us at Scientopia have decided to take a closer look at the science - both good and bad - behind the articles in the latest issue of Women's Health magazine. Be sure to check out the Scientopia front page where you can find all the Women's Health review posts

We're suffering from a heat wave here in Southern California.  Today the temperature is expected to hit triple digits by mid-afternoon, while the relative humidity is expected to drop to a dry 10%. Dehydration is a serious concern, especially for people who have to spend time outside during the hottest part of the day. It's a lifesaver that clean water is as close as the nearest faucet.

That brings me to the article1 in Women's Health that asks "Think that's clean water coming out of your faucet?" The answer, of course, is that there are a "host of nasties" we should be concerned about. It lists four pollutants that may be found in your tap water: chlorine, lead, bacteria, and hormone and drug by-products, that has a take-home message that we should be very concerned about the toxins in the water we drink.

So should we avoid drinking water from the faucet? or is it scare-mongering? While there are indeed legitimate concerns about the safety of the water supply, I'd say the short piece makes it sound as if contaminated tap water is a much greater problem than it really is.

Water Treatment Cycle (click for details)

There is no one single source of tap water in the United States2. There are more than 150,000 public water systems in the US, supplying drinking water to the vast majority of Americans. The quality of the water varies depending on the source and the efficiency of local water treatment. But even so, the public drinking water supply is required to meet the safety standards overseen by the  Environmental Protection Agency.

So what do we actually know about the "nasties" in our water supply?  Read on.

Nasty Chlorine

In 1908 Jersey City, New Jersey became the first municipal water system in the United States to disinfect its water supply with chlorine. The treatment is very effective at killing bacteria, viruses, and parasites. Today, a century later, disinfection of drinking water has virtually eliminated water-borne diseases like cholera and typhoid fever in the U.S.

The problem is that in addition to killing pathogens, chlorine can chemically react with organic compounds in the water, creating toxic by-products, particularly trihalomethanes (THM). Those are the the "nasties" that the article refers to:

But studies show that long-term exposure to chlorine by-products can lead to miscarriage or birth defects, says Gina Solomon, M.D., a senior scientist at the Natural Resources Defense Council.

That's scary!  But how great is the actual risk?

A search of the recent medical literature turns up some studies that found a relationship between exposure to chlorination by-products and birth defects, and others not so much.  A recent review of the literature found that isn't enough evidence to conclude that the by-products create a significant risk of birth defects.  A  different review, looking at a slightly different set of studies did find a moderate association between chlorination by-products and miscarriages, particularly in women who drink five or more glasses of tap water per day.

So there may be a small risk of drinking tap water during pregnancy. Fortunately, many public water suppliers have begun to use chloramine, rather than chlorine, as a disinfectant. That reduces the total level of disinfection by-products, which is step in the right direction.

You can also help remove the contaminants yourself. Most of the chlorination by-products are volatile, meaning that they will eventually evaporate. The Women's Health article suggests letting the water stand 5 minutes before drinking, but that doesn't seem like nearly long enough to make a difference. The World Health Organization suggests boiling for 5 minutes to remove THM.  You'd probably have to let the water stand at room temperature for several hours to have the same effect.

And if you are seriously concerned, don't forget that showering, bathing and swimming in chlorinated pools likely also contribute to trihalomethane exposure.

Further reading:

Nieuwenhuijsen MJ et al. Chlorination Disinfection By-Products in Drinking Water and Congenital Anomalies: Review and Meta-Analysis. Environ Health Perspect. 2009 October; 117(10): 1486–1493. doi: 10.1289/ehp.0900677.

Bove F. et al. Drinking water contaminants and adverse pregnancy outcomes: a review. Environ Health Perspect. 2002 February; 110(Suppl 1): 61–74. (full text)

Environmental Protection Agency: Basic Information about Disinfection Byproducts in Drinking Water: Total Trihalomethanes, Haloacetic Acids, Bromate, and Chlorite

World Health Organization:  Trihalomethanes in drinking-water (pdf).

Nasty Bacteria

Scanning electron micrograph of E. coli.

Treatment of water with chlorine or other disinfectants kills the microbes that can make you sick. But sometimes water isn't adequately treated and pathogens can end up in your drinking water. Or as Women's Health put it:

Gnarly bacteria like E. coli can make their way into water from human and animal waste that runs into reservoirs from broken pipes and sewage systems.

E.coli infection is spread through ingestion of poop from infected animals or humans, and it can indeed be spread through drinking contaminated water, as well as eating contaminated or by contact with infected individuals. However, it's rare that it finds its way into the water coming out of your tap. Let's look at some numbers.

According to the CDC, in 2005 and 2006 there were a total of 20 disease outbreaks associated with drinking water in the U.S., affecting 612 people. To put that into perspective, that is about 300 people affected by drinking water-associated disease outbreaks per year out of a total U.S. population of roughly 300 million. Even factoring in the likelihood that some small outbreaks went unreported, such outbreaks are rare.

Twelve of those twenty outbreaks - affecting 135 people -  were associated with bacterial contamination. Ten were caused by Legionella in contaminated building plumbing systems; one outbreak was caused by Campylobacter, and a single outbreak was caused by pathogenic E. coli.  The E.coli outbreak affected 60 people at a camp in Oregon that was supplied with inadequately chlorinated river water.

It looks to me that as long as your local water treatment facility is functioning properly, the risk of infection from drinking tap water is extremely low.

Of course for someone who has a compromised immune system or is otherwise vulnerable to infection, even a small risk can pose a danger. Fortunately there is an easy solution: boiling water before drinking it should kill any microbes lurking within.

Further reading:

CDC Morbidity and Mortality Weekly Report Surveillance Summary:  Surveillance for Waterborne Disease and Outbreaks Associated with Drinking Water and Water not Intended for Drinking --- United States, 2005--2006 (pdf version)

Tomorrow: Lead and pharmaceuticals.


1. It's actually not so much an article as a "List Tool", that breaks down a topic into 4 or 6 or 8 pithy points.

2. Women's Health is a U.S. magazine, so I'm assuming they are referring to the U.S. water supply.

4 responses so far