Some work recently out of my former institute, Eawag, has been optimizing a novel method, flow cytometry, to measure microbes swimming/floating in water. A couple of fluorescent DNA dyes are added to the water, then as a very narrow capillary stream flows by a laser, the cell numbers are counted. Initial results have shown that there are a lot more microbial cells in water supplies than we might like to think. Ambient water in the environment (e.g., a lake) generally has maybe 10^7 cells per milliliter (i.e., 10,000,000 cells per drop of water). A soil or sediment has 1-2 orders of magnitude more cells per milliliter in general. The flow cytometry results show that treated drinking water has roughly 10^5 cells per milliliter (i.e., 100,000 cells per drop of water). That’s a lot of microbes in your water! Time to freak out, set your hair on fire, and switch to bottled water! The government is trying to kill you!!
Ok, it’s not that bad. When water leaves a drinking water treatment plant, it is usually given a healthy dose of chlorine (“chlorine residual”) to keep microbial growth low in the piping network to your house. Furthermore, there are tests for potentially dangerous bacteria, with standards to be met before the water is allowed to be delivered to you. A common problem with standard tests is that they require the cells to grow on agar plates, even though many cells don’t grow under those conditions, and the results take up to 3 days. Flow cytometry is available just minutes after sample collection. The Eawag method has revealed that the standard test is a little misleading — no “bad” microbes doesn’t mean no microbes at all, and that’s ok.
What’s interesting is that the Swiss authorities have added this method to the list of acceptable tests for drinking water quality. Who knows, maybe you’ll soon see this method coming to a water treatment plant near you!
Oh, and if you were going to switch to bottled water, just remember, it might have more microbes in it than tap water. It will be ok.
With a background in civil engineering, I’m partial to infrastructure. I find bridges absolutely fascinating. I also know that the US is far behind in funding necessary improvements to existing infrastructure, from bridges and highways to water and wastewater treatment. The American Society of Civil Engineers gives our infrastructure a D, with water and wastewater treatment getting D minuses. Yikes. I’m holding out for a miracle of stimulus to bring our facilities up to par, but there’s a country we might look to for guidance: China (gulp).
China has been investing tons of money in infrastructure, from building a vast highway network in anticipation of cars to use it, to top-of-the-line subways and airports. But they’re falling short of goals to deliver safe drinking water to all residents. About one in five Chinese residents must boil his/her tap water before use, and that doesn’t include the safety issues from metals and organic chemicals in the water. Some city planners have complained that water treatment facilities are too expensive. Welcome to the first world, China, where we’re still trying to sort out that very issue…(see above ASCE grade and our lack of funding to address that grade).
A recent rainstorm killed 37 people due to flooding in Beijing, and it left some wondering whether key infrastructure has been neglected in the nation’s recent great leap of progress. Homes collapsed, streets flooded, and power lines fell.
The city has seen tens of billions of dollars poured into its modernization, including iconic venues for the 2008 Olympics, the world’s second-largest airport, new subway lines and dazzling skyscrapers — all while basics like water drainage were apparently neglected.
Has China given us an example of a “bad” stimulus? Or perhaps just a lesson in risk assessment and investment protection — in order to preserve those new buildings and roads and bridges long enough to truly pay off, basic water management infrastructure is a requirement, too. I hope that the US will learn from this sad example.
As you surely know, fracking gets a lot of publicity these days. One thing that gets less publicity is the science about fracking. In the case of the threat that fracking poses to drinking water supplies, things have gotten a little out of hand. The image of lighting one’s tap water on fire is pretty powerful stuff. But from what I’ve read, it sounds like the initial issues with fracking fluid and natural gas entering local aquifers derived mainly from poor well construction, specifically the well casings, by inexperienced workers eager to cut corners to make more money. Furthermore, the wells affected were generally private wells, owned by the very landowners making money off the natural gas being extracted. Private wells are not subject to the same rigorous testing as public wells and public water supplies, although the EPA recommends that well owners have their wells tested regularly. So these issues have not generally affected public water supplies.
That’s not what the public believes. A recent survey published in Environmental Science and Technology found that more Dallas residents worried that fracking was the greatest threat to their water supply [27%] than knew that they lived in a watershed [10%]. (Hint on the watershed question: you live in one.) This is not just another sad comment on the lack of public science education, rather this is a key piece of information when we discuss water use in general. Urban water use drives demand in most American cities, not industrial use. Cutting back on urban water consumption in places like Dallas, with a per capita water use of ~220 gallons per day, has far greater potential impact on the regional water balance than fracking could ever hope to have. The major coastal cities in California use closer to ~120 gallons per person per day, so it can be done.
I was riding BART the other night, trying to mind my own business despite a loud group of French teenagers. My ears perked up, though, when one teenager asked her chaperone, a young American woman about my age, if it was safe to drink the tap water everywhere in the US. At first I was annoyed that Europeans consider us so third-world as to even need to ask such a thing. (In China, for example, no city yet delivers safe tap water to all its residents.) But then the American’s response floored me: “Uh, sure, maybe except in areas with a lot of fracking.” It took all of my willpower not to launch into a tirade of facts about water. It’s frankly impressive how quickly environmentalists have won the P.R. battle about fracking. If only we could harness that momentum to educate the public about far more pressing issues when it comes to water supply…
Note: Sorry to readers about the gap in posts. This week has been pretty busy, but I hope to get back to posts every 1-2 days.
Today’s news includes another way that you can distinguish yourself from less worthy peers: boutique water. A New York City shop has a 7-step ultrafiltration unit to purify NYC tap water into “pure water”. The taste is supposedly “‘fluffy’ with a ‘smooth’ finish”, which might be fine and good, but that’s the taste of flushing out your body’s minerals and nutrients! My understanding is that this equipment is basically laboratory-grade water purification, which I have used quite a bit, but have never drunk. As most of you probably know, all water naturally has dissolved minerals — cations and anions like sodium, calcium, magnesium, chloride, and sulfate — that provide most of the flavor as well as the osmotic balance for the body’s cells. If you consume ultrapure water in large quantities, you could potentially flush out most of your cells’ nutrients and minerals via osmosis! (Just drinking large quantities of water alone will do this, too: http://en.wikipedia.org/wiki/Water_intoxication).
Ah, but if the palate knows, it knows. I happen to know that New York City has some of the best tap water in the world, and it comes much cheaper than any boutique water…