Dear EarthTalk: Why is chlorine added to tap water? Do water filters effectively filter it out?
—J.P. Miller, Hudson, WI
Chlorine is a highly efficient disinfectant, and it is added to public water supplies to kill disease-causing bacteria that the water or its transport pipes might contain. "Chlorine has been hailed as the savior against cholera and various other water-borne diseases, and rightfully so," says Steve Harrison, president of water filter maker Environmental Systems Distributing. "Its disinfectant qualities
have allowed communities and whole cities to grow and prosper by providing disease-free tap water to homes and industry."
But Harrison says that all this disinfecting has not come without a price: Chlorine introduced into the water supply reacts with other naturally occurring elements to form toxins called trihalomethanes (THMs), which eventually make their way into our bodies. THMs have been linked to a wide range of human health maladies ranging from asthma and eczema to bladder cancer and heart disease. In addition, Dr. Peter Montague of the Environmental Research Foundation cites several studies linking moderate to heavy consumption of chlorinated tap water by pregnant women with higher miscarriage and birth defect rates.
A recent report by the non-profit Environmental Working Group concluded that from 1996 though 2001, more than 16 million Americans consumed dangerous amounts of contaminated tap water. The report found that water supplies in and around Washington, D.C., Philadelphia and Pittsburgh in Pennsylvania, and the Bay Area in California were putting the greatest number of people at risk, although 1,100 other smaller water systems across the country also tested positive for high levels of contaminants.
"Dirty water going into the treatment plant means water contaminated with chlorination byproducts coming out of your tap," said Jane Houlihan, EWG's Research Director. "The solution is to clean up our lakes, rivers and streams, not just bombard our water supplies with chlorine."
Eliminating water pollution and cleaning up our watersheds are not going to happen overnight, but alternatives to chlorination for water treatment do exist. Dr. Montague reports that several European and Canadian cities now disinfect their water supplies with ozone instead of chlorine. Currently a handful of U.S. cities do the same, most notably Las Vegas, Nevada and Santa Clara, California.
Those of us who live far from Las Vegas or Santa Clara, though, do have other options. First and foremost is filtration at the faucet. Carbon-based filters are considered the most effective at removing THMs and other toxins. The consumer information website WaterFilterRankings.com compares various water filters on the bases of price and effectiveness. The site reports that filters from Paragon, Aquasana, Kenmore, GE and Seagul remove most if not all of the chlorine, THMs and other potential contaminates in tap water.
Concerned consumers without the money to spend on home filtration, though, can just rely on good old-fashioned patience. Chlorine and related compounds will make their way out of tap water if the container is simply left uncovered in the refrigerator for 24 hours.
Dear EarthTalk: Have high oil prices of late really caused Americans to buy fewer SUVs, or is this just a myth?
—Shane Wiener, Royal Oak, Michigan
It is indeed true that sales of sport utility vehicles (SUVs)—not to mention pickup trucks and vans—have plummeted in recent months in the U.S. Undoubtedly rising oil prices are playing a big role, and sales of the Ford Explorer, Lincoln Navigator, GMC Yukon and Hummer H2 are all down 50 percent or more.
But U.S. automakers are quick to point out that sales have been dropping across all product lines and that attractive financing programs last year translated into record sales numbers. But General Motors (GM), the world's largest automaker, did report that overall sales in the U.S. sank in October 2005 by 22.7 percent compared to the previous year, while sales of SUVs, pickups and vans shrank by a whopping 30.3 percent. Meanwhile, Ford Motor Company experienced similar drops.
"We realize that gas prices are important to consumers and we're certainly not denying that there's an impact," says Paul Ballew of GM, who thinks the change in consumer preference is not as significant as it was following the world's first round of oil shocks three decades ago. "We are seeing more interest in consumers understanding fuel economy of vehicles. But there's not the shift we saw in the 70's and 80"s."
Against this backdrop of gloom for American automakers, Japanese competitors specializing in smaller cars have reported banner sales numbers in recent months. Toyota, maker of the industry-leading gas-electric hybrid Prius, beat its own October U.S. sales numbers from a year earlier by 5.2 percent, while Honda, which offers the world's most fuel-efficient traditional cars as well as hybrids, saw its U.S. sales rise four percent in October. Toyota's SUV and pickup sales slackened by four percent, while Honda bucked the downward trend by staying even with last year with its light truck line.
One sign of flagging consumer demand for gas-hogging large SUVs is the recent development of so-called crossovers, which are SUV-type vehicles built on smaller, more fuel efficient frames. These vehicles, such as the Chrysler Pacifica and the Toyota Highlander, appeal to consumers looking for better gas mileage but unwilling to give up the SUV's size. Today almost half of all light trucks sold are considered crossovers. Just two years ago, such vehicles accounted for only about 16 percent of the country's light truck fleet.
Another new option for light truck lovers looking to save gas and money is the hybrid SUV, which, like a hybrid car, utilizes both gasoline and electric engines to maximize fuel efficiency. Ford and Toyota lead the pack in hybrid SUV sales, but new models on the way from GM promise to provide consumers with even more ways to live large with less guilt.
CONTACTS: Toyota Highlander, www.toyota.com/highlander; Highlander Hybrid SUV, www.toyota.com/vehicles/minisite/hhybrid/index.html; Chrysler Pacifica, www.chrysler.com/pacifica; Ford Hybrid SUV, www.fordvehicles.com/escapehybrid/home; U.S. Department of Energy's fueleconomy.gov, www.fueleconomy.gov.