Bottlemania - Elizabeth Royte [44]
For that we can thank the managers of water plants, who aren’t a celebrated lot. They play the hand they are dealt, in terms of source water, and if they do their job well, few notice. If they’re in the news, it’s because something went massively wrong. Mike Klender makes it sound easy to make good water from oil spills, industrial discharges, agricultural runoff, animal waste, treated sewage, and raw sewage (more than 850 billion gallons of which flow into U.S. waterways each year from overburdened systems). But it’s not simple, and many utilities struggle.
In 1993, both Washington, D.C., and New York City found unacceptable levels of E. coli in their water supplies. To protect the public from such outbreaks, the EPA in 2002 began requiring cities that drink unfiltered surface water to use two disinfection methods instead of one. Some cities opted to kill pathogens by exposing their water to ozone, an extreme oxidant. Others decided to run their water past lamps emitting ultraviolet radiation. Both methods are far cheaper than filtering. When New York completes its UV plant, in 2010, it will be the largest in the world.
“It’s a belt-and-suspenders approach,” Alan Steinberg, the EPA administrator whose region of responsibility includes New York and New Jersey, says. Ultraviolet light, Steven Schindler, New York City’s director of drinking-water quality control, tells me when I visit DEP headquarters in Queens, “inactivates” cryptosporidium, a microscopic parasite that can cause disease but is resistant to chlorine.
“You mean it kills the crypto?”
Schindler hesitates. “It destroys their ability to reproduce.” Either dead or sterile, they can do us no harm.
Cryptosporidium occurs in 65 to 97 percent of surface waters in the United States, according to the Centers for Disease Control and Prevention. In 1993, more than four hundred thousand people were sickened, and sixty-nine people died, when the parasite made its way from farms and forests into Lake Michigan and then into Milwaukee’s drinking-water supply. The city has since tightened its purification and testing procedures and added ozone disinfection. Investigations showed that New York’s crypto comes not from human poop but from deer, opossum, and skunk—which I find strangely reassuring.
Using ultraviolet light lets utilities cut back their use of chlorine, which, again, reacts with organic material to form disinfection by-products. All cities wrestle with the right formula: use too little chlorine and microbes survive. Use too much, and you get potential carcinogens. “Disinfectants limit microbial risk; infectious disease is the major concern,” says Robert D. Morris, an environmental epidemiologist and the author of The Blue Death: Disease, Disaster, and the Water We Drink, which both defends and attacks our drinking-water system. “If people get cancer in twenty to thirty years, no one is going to take the water department to task for that. So water managers aren’t anxious to see new rules that lower disinfection by-products.” (A Brita filter, like other pitchers certified by the NSF/ANSI Standard 42, will substantially reduce some of these chlorine by-products, but it won’t eliminate any of them. Brita is, by the way, owned by the Clorox Company.)
Nearly a third of water utilities in the nation, Kansas City included, have thrown in the towel, switching from chlorine to the chlorine-and-ammonia mixture known as chloramine. But this compound has downsides too. For one thing, chloramine isn’t as strong a disinfectant as chlorine. To remove sludge and sediment from its pipes, Washington, D.C., which switched to chloramines in 2004, annually conducts a good old-fashioned “chlorine burn.” The high dose, predictably, increases levels of disinfection by-products. Utility officials maintain that D.C. water, which comes from the Potomac, still meets EPA safety standards because levels are averaged over the year.
Second, some studies suggest