In the era of the CFL and LEDs, looking back at Edison’s 1879 incandescent invention

Today marks the 130th anniversary of Thomas Alva Edison’s invention of the first commercially viable incandescent lightbulb. (The image, from the National Archives, is from Edison’s patent application; he received the patent in early 1880.) And while incandescents are still being improved upon to be more energy efficient, the emphasis today is on compact fluorescent lighting and LEDs, like those vying for the L Prize in the U.S. Department of Energy's Bright Tomorrow Lighting Prizes competition.

Check out our latest report on and ratings of compact fluorescent lightbulbs and learn how to save money on your annual utility bill.

Essential reading: Find out how to choose CFLs, read "10 Questions for . . . Nadarajah Narendran, Ph.D., Lighting Researcher" for news on advances in lighting technology, and see what European consumers think about the EU's ban on some incandescent lightbulbs.

Recent study points to showerheads as bacterial breeding ground

Taking a shower can provide a bracing wake-up call or settle the nerves after a hectic day. But a new study from the University of Colorado, which suggests that the typical showerhead can be an ideal breeding ground for bacteria commonly found in municipal water supplies, might give you pause the next time you step into the shower. The study, "Opportunistic Pathogens Enriched in Showerhead Biofilms," appeared in a recent online edition of the Proceedings of the National Academy of Sciences.

Begun as a class project, the study expanded to include 45 sites in nine metropolitan areas, including New York, Chicago, and Denver. Through the very DNA of the pathogens lodged in the nooks and crannies of about 50 showerheads, researchers identified numerous bacteria, notably Mycobacterium avium, a relative of the organism that causes tuberculosis (PDF).

Bacteria found in showerheads tend to clump together in slimy biofilms, the so-called soap scum that builds up on the showerhead's plastic components, explained Norman R. Pace, Ph.D., lead study author and a professor of microbiology at the university. When a shower is on, pathogens accompany the water droplets that become suspended in the air. Besides coating the shower-curtain liner or walls of the shower enclosure, these droplets are easily inhaled deeply into the lungs.

M. avium, often present in soil, is among a class of nontuberculous mycobacteria, or NTM, described as "ubiquitous" by the U.S. Centers for Disease Control and Prevention. But although M. avium accounts for most known infections by NTM, M. avium has not been well documented as a source of infection since suspected cases of NTM infection don't have to be reported to the CDC.

What's certain is that, while M. avium complex, or MAC, is unlikely to affect most people, if contracted it could potentially cause pulmonary disease, with symptoms similar to those of tuberculosis, including a chronic shallow cough, fever, fatigue, and weight loss. Most at risk, however, are those with compromised immune systems, including people with cystic fibrosis or AIDS or who are elderly, pregnant, or otherwise immune compromised.

The study focused on showerheads, but your home has other potential hot spots, such as a humidifier not cleaned thoroughly, hot tubs, and food-prep areas. Even indoor air carries bacteria, but municipal tap water has 10 times the amount commonly found in indoor air before it even reaches the showerhead. And there's no proof that raising the temperature of your water heater would make a significant difference; the culprit is continuous moisture.

Whether or not you're especially at risk, here's what you can do to try to prevent any bacterial problems in the shower:

10 Questions for . . . Arlene Blum, Biophysical Chemist

In this installment of 10 Questions for . . . , Associate Editor Kimberly Janeway speaks with Arlene Blum, Ph.D., a biophysical chemist, author, and avid mountaineer. Blum recently won a Purpose Prize for 2008, which recognizes individuals 60 and older who are working to solve some of society's pressing problems. Blum won for her work to mobilize scientists, industry, and consumers to limit toxins in household products. Here's her take on toxins—including their impact on humans and consumer awareness—and the link between mountain climbing and her current work.

How are you working to limit toxins?
I'm executive director of the Green Science Policy Institute, and we're bringing scientific unbiased peer-reviewed data to government, industry, and nongovernmental groups to help make more informed decisions about which chemicals should be used in consumer products. We've stopped 10 bad standards just by putting together good information and people.

What's your latest achievement here?
We mobilized scientists, firefighters, and nonprofits around the world to persuade the International Electrotechnical Commission to reject a flammability standard that would have resulted in adding unneeded and potentially toxic fire retardants in the plastic enclosures of all consumer electronics, such as computers and printers.

Are chemicals in household products tested for their long-term effects on human health and the environment?
Our government requires health information only for foods, drugs, and pesticides. Consumers have no protection at all against toxic chemicals in household products.

What's the standard in Europe?
In Europe they reverse the burden of proof. Manufacturers have to show that chemicals are safe before they introduce them. In the U.S., chemicals are innocent until proven guilty.

How do toxic chemicals affect human health?
A big chunk of cancers, birth defects, thyroid disease, and neurological and reproductive impairments may be environmentally based. Reducing toxic chemicals in our homes and our bodies could help reduce these problems. I'm especially concerned about the chemicals that are persistent and biocumulative. These chemicals can migrate out of our couches and our TVs into dust and then into our bodies. Some are fat-loving and can stay in our fat for a very long time. They can also wind up in soil and rivers and then make their way into our food supply.

In 1977, your research led to a ban of the fire retardant Tris in children's garments, including sleepwear. How did Tris affect children?
We found that as soon as kids put on pajamas, you could find cancer-causing breakdown products in their urine the next morning. Tris was immediately taken out of sleepwear, but it's now being used in furniture foam.