ACS News Service Weekly PressPac: May 21, 2008

• Melting glaciers may release DDT and contaminate Antarctic environment
• Light-driven "molecular brakes" provide stopping power for nanomachines
• Next-generation explosives: More power and safety without the pollution
• Rice in your gas tank: Boosting biofuel production from rice straw
• Electronic waste disposal: A growing challenge

In an unexpected consequence of climate change, scientists are raising the possibility that glacial melting is releasing large amounts of the banned pesticide DDT, which is contaminating the environment in Antarctica. The study is scheduled for the June 1 issue of ACS’ bi-weekly journal Environmental Science & Technology.

In the study, Heidi N. Geisz and colleagues estimate that up to 2.0-8.8 pounds of DDT are released into coastal waters annually along the Western Antarctic Ice Sheet from glacial meltwater. The researchers point out that DDT reaches Antarctica by long-range atmospheric transport in snow, and then gets concentrated in the food chain. DDT has been banned in the northern hemisphere and has been regulated worldwide since the 1970s. Geisz found, however, that DDT levels in the Adelie penguin have been unchanged since the 1970s, despite an 80 percent reduction in global use.

Global warming may explain that contradiction, they say. As the annual winter temperature on the Antarctic Peninsula has increased by about 10 degrees Fahrenheit in the last 30 years, glaciers have retreated. The possibility that glacial meltwater has contaminated Antarctic organisms with DDT, the study says, “has compelling consequences” if global warming should continue and intensify.

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Scientists in Germany are reporting development of a new generation of explosives that is more powerful than TNT and other existing explosives, less apt to detonate accidentally, and produce fewer toxic byproducts. Their study of these more environmentally friendly explosives is scheduled for the June 24 issue of ACS’ Chemistry of Materials, a bi-weekly journal.

In the new study, Thomas M. Klapötke and Carles Miró Sabate point out that conventional explosives such as TNT, RDX and HMX, widely-used in military weapons, are rich in carbon and tend to produce toxic gases upon ignition. In addition to polluting the environment, these materials are also highly sensitive to physical shock, such as hard impacts and electric sparks, making their handling extremely dangerous. Greener, safer explosives are needed, the researchers say.

To meet this need, Klapötke and Sabate turned to a recently explored class of materials called tetrazoles, which derive most of their explosive energy from nitrogen instead of carbon. They identified two promising tetrazoles: HBT and G2ZT. The researchers developed tiny “bombs” out of these materials and detonated them in the laboratory. The materials showed less sensitivity to shock than conventional explosives and produced fewer toxic products when burned, the researchers say.

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Millions of tons of unwanted computers, cell phones and other electronic waste (E-waste) are filling the world’s recycling bins each year. But the lack of standardized recycling methods and E-waste’s potentially toxic health effects have sparked a growing debate over how to deal with this tsunami of cast-off technology, according to an article scheduled for the May 26 issue of Chemical & Engineering News, ACS’ weekly newsmagazine.

C&EN Senior Editor Jeff Johnson points out that barely 15 percent of the estimated two million tons of E-waste produced each year in the United States is recycled or reused. Leftovers are often shipped to poorer countries like Africa, India, or China, where workers face health dangers as they attempt to remove lesser valued, more toxic parts, the article notes.

But change may be around the corner. Environmental advocates, community groups, Congress, and some in the electronics industry are seeking alternatives to these “informal” recycling efforts, including the manufacture of “greener” electronic parts and equipment, tougher regulations on the disposal and shipping of E-waste, and “take back” programs that encourage manufacturers to collect the E-waste that they produce, according to the article.

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• Press releases, chat room sessions, and more from ACS’ 235th National Meeting

It’s never too late to explore a treasure trove of news sources, background material and story ideas available from the ACS' latest National Meeting, which was held in New Orleans from April 6-10, 2008. Reporters can view press releases, search an archive with abstracts of 9,000 scientific presentations and hundreds of non-technical summaries of those presentations, and access other resources at: www.eurekalert.org/acsmeet.php.

The ACS Office of Communications also offers recorded video versions of its national meeting “chat room” briefings and accompanying chat transcripts at http://www.ustream.tv/search/recorded/tag/ACS To use this site, you must first register with Ustream.tv by going to http://ustream.tv/sign-up-step-1. It’s free and only takes a minute or two to sign up. To view the archived chat room sessions, proceed by clicking the “Login” button at the top right of the Ustream window and then selecting “Past Clips.” Please note that Ustream requires the latest version of Adobe Flash, which can be downloaded without charge at http://www.adobe.com/products/flashplayer.

• ChemMatters Matters for Journalists

This quarterly ACS magazine for high school chemistry students, teachers, and others explains the chemistry that underpins everyday life in a lively, understandable fashion. ChemMatters is available at www.acs.org/chemmatters. You can also receive the most recent issues by contacting the editor, Pat Pages, at: 202-872-6164 or chemmatters@acs.org.

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