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ACS News Service Weekly PressPac: July 26, 2006

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News Items in this Edition

First system for monitoring lead poisoning in living cells

Despite lead poisoning’s status as the world’s most common environmentally caused disease, no practical medical test exists to monitor the amount of lead present in living cells over time. Existing laboratory tests can only measure total lead content in cells, rather than provide critical information on the amount of biologically available lead, which is what causes lead poisoning.

Christopher J. Chang and colleagues now report development of the first fluorescent sensor molecule that can monitor changes in lead levels in living cells. Their study is scheduled for the July 26 issue of the Journal of the American Chemical Society. The sensor, which the researchers term Leadfluor-1 (LF1), turns on in the presence of lead with intensities that reflect the amount of lead present in living cells.

Those levels of lead might rise with exposure to lead in the environment, for instance, or decline with successful treatment of lead poisoning. Doctors and patients would benefit from the ability to monitor such changes.

Researchers explain that the new turn-on fluorescent lead sensor has several advantages over previous sensors. It tracks the specific chemical form of lead responsible for lead poisoning. In addition, it fluoresces in response to visible light, avoiding interference from biological molecules and other sources that occurs with other sensors that respond to ultraviolet light.

The cost of pollution at Southern California beaches

Removing fecal contamination from the waters off Southern California beaches could prevent up to 1.5 million cases of gastrointestinal illness among swimmers and other recreational water users annually, a new study has found. It is scheduled for publication in the Aug. 15 issue of ACS’ Environmental Science & Technology.

Linwood H. Pendleton, of the University of California at Los Angeles, headed the study, which was conducted with colleagues from Stanford University. The researchers used beach attendance data, fecal coliform densities and two epidemiological models to estimate the risk of GI illness at 28 beaches that stretch along 99 miles of coastline in Los Angeles and Orange counties.

They found that anywhere from about 628,000 to 1,479,000 cases of GI illness — which involves diarrhea, vomiting and other symptoms — occur annually as a result of fecal contamination of the water. The researchers estimated that health care costs for those cases range from $21 million annually (based on very conservative assumptions) to $414 million.

The study, which includes data for individual beaches, concludes that water quality improvements in the region could have substantial public health benefits.

Boosting levels of healthful nutrients in watermelon

Whole watermelons stored at 70 degrees F. — roughly room temperature in air-conditioned environs — have substantially more healthful nutrients than refrigerated melons, U. S. Department of Agriculture scientists report. Watermelon is a rich source of carotenoid compounds, natural antioxidants linked to a variety of health benefits. Watermelon contains higher levels of lycopene, for instance, than any other fresh fruit or vegetable. That red pigment is found in only a few other foods, notably tomatoes.

Penelope Perkins-Veazie and Julie K. Collins realized that there was no data on changes in lycopene and other carotenoids in watermelon during storage. They analyzed carotenoid content in several popular varieties of watermelon stored for 14 days at 70 degrees, 55 degrees and 41 degrees. Their findings are scheduled for the Aug. 9 issue of the ACS’ Journal of Agricultural and Food Chemistry.

Compared to freshly-picked fruit, watermelon stored at 70 degrees gained 11 percent to 40 percent in lycopene and 50 percent to 139 percent in beta carotene. Carotenoids in watermelon stored at lower temperatures, in contrast, remained about the same.

Arsenic leaching remains a problem in mulch made from recycled wood

New research challenges the idea that colorant added to a popular kind of mulch — made from construction and demolition debris — prevents release of arsenic from chemically treated wood sometimes used to make that mulch.

Past studies have found that recovered wood at debris recycling facilities may contain up to 30 percent chromated copper arsenic-treated (CCA) wood. Helena M. Solo-Gabriele and colleagues point out that even small amounts of CCA-preserved wood (recently banned for residential uses) can cause mulch to exceed regulatory guidelines for arsenic leaching.

A colorant made from iron oxide usually goes into mulch made from recycled wood to give it the appearance of natural wood mulch. Iron oxide binds arsenic, which raised hopes that artificially colored mulch would not leach potentially harmful amounts of arsenic.

The new study, scheduled for the Aug. 15 issue of ACS’ Environmental Science & Technology, found that colorant reduced leaching of arsenic by more than 20 percent. However, leaching still exceeded regulatory guidelines and the effect lasted only for the first few months after mulch application.

Bittering bills aim to prevent child and pet antifreeze poisonings

The U. S. Congress is eyeing a powerful bittering agent as a way to prevent thousands of annual child poisonings and tens of thousands of pet deaths linked to accidental ingestion of ethylene glycol antifreeze, according to a report scheduled for the July 31 issue of Chemical & Engineering News, the ACS’ weekly newsmagazine.

Automobile radiator antifreezes and engine coolants that contain ethylene glycol are toxic, C&EN senior editor Cheryl Hogue explains in the article. They also have a sweet taste that leads to accidental poisonings. A few of licks, for instance, can be fatal to a cat or dog.

Antifreeze bittering bills pending in the House and Senate would require manufacturers to add denatonium benzoate (DB) to these ethylene glycol automotive fluids. DB has an intensely bitter taste and has been used in other consumer products for more than 40 years.

Although the legislation has garnered broad support, there are lingering doubts, Hogue points out. One is whether DB actually will discourage antifreeze consumption by pets. There also is concern that DB automotive fluids may find their way into drinking water supplies and make drinking water from some sources unpalatable.

“Safer Antifreeze Bill is Moving Fast: Congress is on the verge of mandating a bitter additive, but chemical may not deter pets”

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  • Science, September & San Francisco
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232nd ACS National Meeting in San Francisco

September 10-14 is one of the year’s biggest and most influential scientific conferences – the 232nd ACS national meeting in beautiful San Francisco.

The American Chemical Society – the world’s largest scientific society – is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.