Week of 10/28/2007

Dear EarthTalk: Are the rumors true that refilling and reusing some types of plastic bottles can cause health problems?

—Regina Fujan, Lincoln, NE

Most types of plastic bottles are safe to reuse at least a few times if properly washed with hot soapy water. But recent revelations about chemicals in Lexan (plastic #7) bottles are enough to scare even the most committed environmentalists from reusing them (or buying them in the first place). Studies have indicated that food and drinks stored in such containers—including those ubiquitous clear Nalgene water bottles hanging from just about every hiker’s backpack—can contain trace amount of Bisphenol A (BPA), a synthetic chemical that interferes with the body’s natural hormonal messaging system.

The same studies found that repeated re-use of such bottles—which get dinged up through normal wear and tear and while being washed—increases the chance that chemicals will leak out of the tiny cracks and crevices that develop over time. According to the Environment California Research & Policy Center, which reviewed 130 studies on the topic, BPA has been linked to breast and uterine cancer, an increased risk of miscarriage, and decreased testosterone levels. BPA can also wreak havoc on children’s developing systems. (Parents beware: Most baby bottles and sippy cups are made with plastics containing BPA.) Most experts agree that the amount of BPA that could leach into food and drinks through normal handling is probably very small, but there are concerns about the cumulative effect of small doses.

Health advocates also recommend not reusing bottles made from plastic #1 (polyethylene terephthalate, also known as PET or PETE), including most disposable water, soda and juice bottles. According to The Green Guide, such bottles may be safe for one-time use, but reuse should be avoided because studies indicate they may leach DEHP—another probable human carcinogen—when they are in less than perfect condition. The good news is that such bottles are easy to recycle; just about every municipal recycling system will take them back. But using them is nonetheless far from environmentally responsible: The nonprofit Berkeley Ecology Center found that the manufacture of plastic #1 uses large amounts of energy and resources and generates toxic emissions and pollutants that contribute to global warming. And even though PET bottles can be recycled, millions find their way into landfills every day in the U.S. alone.

Another bad choice for water bottles, reusable or otherwise, is plastic #3 (polyvinyl chloride/PVC), which can leach hormone-disrupting chemicals into the liquids they are storing and will release synthetic carcinogens into the environment when incinerated. Plastic #6 (polystyrene/PS), has been shown to leach styrene, a probable human carcinogen, into food and drinks as well.

Safer choices include bottles crafted from safer HDPE (plastic #2), low-density polyethylene (LDPE, AKA plastic #4) or polypropylene (PP, or plastic #5). Consumers may have a hard time finding water bottles made out of #4 or #5, however. Aluminum bottles, such as those made by SIGG and sold in many natural food and product markets, and stainless steel water bottles are also safe choices and can be reused repeatedly and eventually recycled.

CONTACTS: The Green Guide; Environment California; SIGG

Dear EarthTalk: Is it true that global warming can exacerbate allergies?

—Alex Tibbetts, Seattle, WA

Global warming can make allergies worse simply because the major pollen producers that trigger allergic reactions thrive and flourish in warmer air. A recent report from the nonprofit Natural Resources Defense Council (NRDC) entitled "Sneezing and Wheezing: How Global Warming Could Increase Ragweed Allergies, Air Pollution and Asthma" details how ragweed, one of the most common allergens in the U.S., grows faster and for longer periods as air temperatures rise due to climate change.

Ragweed also thrives on direct exposure to carbon dioxide (CO2), so as we emit more of this chief greenhouse gas from our tailpipes and smokestacks, we are unwittingly also causing more allergy-aggravating pollen to be produced. According to Kim Knowlton of NRDC, the group’s analysis shows that "there is a clear interplay" between the onslaught of global warming and increasingly higher levels of ragweed pollen, especially in warmer urban areas already plagued with allergens.

"People living in some of the most populated regions of this country may be feeling the effects of global warming every allergy season," says Knowlton. The NRDC report concludes that an increasing number of the 110 million Americans who live in areas with existing ragweed problems will suffer the consequences of global warming as their noses begin to run and their eyes begin to water. Major metropolitan areas in the U.S. likely to be most affected include Atlanta, Philadelphia, Milwaukee, Los Angeles and Chicago, among other locales.

Public health statistics show that about 36 million Americans suffer from some form of seasonal allergy. While allergies can be annoying in their own right, they are also a main contributor to asthma and other serious respiratory problems, making them a serious health threat in their own right. Some 17 million Americans suffer from asthma, with well over half of them also sensitive to the allergens that can spark an asthma attack. Meanwhile, CO2 emissions also contribute to smog, another trigger for asthma. Thus global warming represents a double whammy for asthmatics with pre-existing allergies.

"Global warming—through both its components and by-products—is creating a perfect storm of sneezing and wheezing for allergy and asthma suffers in the U.S.," says Gina Solomon, a senior scientist in NRDC’s health program. She adds that her group’s recent analysis "shows us that people throughout the U.S.—in the North, South, East and West—will be very personally affected by global warming, and we need pollution controls throughout the country to help offset this problem."

According to NRDC, industrial and personal actions can help reduce increases in allergens and combat their effects. Federal, state and local governments can protect communities by reducing the sources of global warming pollution and by creating better resources for citizens in need of information about pollen levels in their areas. Individuals can reduce their own exposure to ragweed and other allergens by checking news outlets for daily pollen counts before venturing outside for long periods of time.

CONTACT: NRDC, "Sneezing and Wheezing,"