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Volume 85 Issue 28 | p. 56 | Newscripts
Issue Date: July 9, 2007

Newscripts

Department: Newscripts | Collection: Critter Chemistry

Chemical-Free Sunscreen

Newscripts reader Stan Hutchings recently opened his newspaper to find this nonsensical headline: "SUNSCREEN that's free of chemicals all the rage."

The article, which appeared in the Fort Worth Star-Telegram, was extolling the virtues of Burt's Bees' new "chemical free" sunscreen. According to the article, the secret behind the chemical-free sunblock is titanium dioxide, "a mineral that reflects the sun's harmful UVA and UVB rays."

The Fort Worth Star-Telegram notes: "Hempseed oil and wheat grass extract also help protect the skin. Goldenseal, a natural anti-inflammatory, soothes and softens. ... Fans say it works and is far more gentle and much less toxic than many chemical-loaded sunscreens.

"Titanium dioxide is lauded by skin experts as a chemical-free way to block wrinkle-causing UVA rays. Another chemical-free sunscreen to try is Blue Lizard for sensitive skin, which has only two active ingredients-titanium dioxide and zinc oxide—and an SPF of 30."

"Apparently titanium dioxide and zinc oxide are no longer chemicals," Hutchings writes. "Titanium dioxide now seems to be just a 'mineral.' "

Skim Milk Cows

Suncreen: Chemical-free? Creative cows: Making skim milk and methane.
Credit: Dreamstime
8528nscow
 
Suncreen: Chemical-free? Creative cows: Making skim milk and methane.
Credit: Dreamstime

Health-conscious consumers could someday get their LOW-FAT MILK straight from the cow. Scientists at the New Zealand biotech firm ViaLactia Biosciences have bred cows that produce skim milk instead of the full-fat variety.

The low-fat cattle are the daughters of Marge, a mutant cow who was discovered by researchers in 2001, when they screened the milk of millions of cattle in New Zealand. That's when ViaLactia bought Marge from her owner for about $250 and moved her to a secret location.

"Marge looks like an ordinary Friesian cow but has three key differences," ViaLactia Chief Scientist Russell Snell told the Sunday Times, a U.K. newspaper. "She produces a normal level of protein in her milk but substantially less fat, and the fat she does produce has much more unsaturated fat."

Butter churned from Marge's milk stays spreadable when refrigerated. ViaLactia hopes to have herds of mutant cows making the spreadable butter by 2011.

Snells says ViaLactia is pleased that Marge's daughters carry the genetic mutation, but they're hoping she'll also pass the mutant gene along to a son. "To have a bull from Marge's offspring who passes on her traits would be the holy grail," Snell says. "It would allow us to reproduce hundreds of thousands of cows like Marge."

Mooing Out Methane

Low-fat milk isn't the only thing coming from New Zealand's cows. One-third of that country's greenhouse gases—in the form of METHANE—come from ruminant animals, such as cows and sheep.

A ruminant animal makes methane when it digests food in its rumen-part of the digestive tract. The rumen contains about 400 types of microbes that help digest what an animal eats. One of these microbes makes methane. A lone heifer can belch out up to 300 lb of methane each day. And pound for pound, methane is far worse for the atmosphere than CO2.

Animal scientists are trying to reduce the livestock's greenhouse-gas hoofprint by changing what goes on inside their stomachs. The cows and sheep don't absolutely need the methanogenic microbe to survive, so getting rid of the methane could be as simple as getting rid of the microbe.

Certain feed additives, such as vegetable oils and fumaric acid, can also cut a cow's methane production by as much as 20%.

Markus Herrema, a California inventor, has suggested sequestering a cow's methane via a special pouch that's worn over the animal's mouth. According to Wired magazine, the bag captures exhaled methane, then microbes inside the bag consume the gases, growing into a biomass that can be used as a cleaner source of energy.

 

This week's column was written by Bethany Halford. Please send comments and suggestions to newscripts@acs.org.

 
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