The Beat.

Growing Better Plastics

Cargill and Dow Chemical have jointly developed a new plastic from the carbon stored in plant sugars that is environmentally sustainable and competitive with conventional hydrocarbon-based polymers in terms of cost and performance. A new facility is scheduled to begin production of the material, called polylactide (PLA), by late 2001.

Corn is the current source of the polymer feedstock, and researchers are working to convert the process so that plant materials such as rice, wheat, sugar beets, and even agricultural waste can be used. According to Cargill Dow Polymers, production of PLA requires 30-40% less fossil fuel than traditional plastics production, and reduces net [CO.sub.2] emissions since the feedstock crops remove the gas from the air. The new material fits with standard waste management practices and degrades in composting facilities. PLA can be used in a wide number of products including apparel, carpet, food containers, and diapers.

Putting Algae on a Diet

Australian researchers led by Malcolm Robb of the Water and Rivers Commission and D. Grant Douglas of Australia's Commonwealth Scientific and Industrial Research Organisation held the first trial of a method for reducing blooms of toxic blue-green algae. The method involves spraying a clay-based substance called Phoslock over water. It sinks to the bottom, forming a thin layer of sediment that absorbs phosphorus, depriving the algae of a major food source. (In earlier tests, Phoslock absorbed over 90% of phosphorus from water and sediment.) The test was conducted in Perth on a 700-meter stretch of the Canning River, where summer algal blooms are common. Researchers also aerated sections of the river in an attempt to remove another algae food source, nitrogen.

Douglas emphasizes that Phoslock is not a "quick fix" for affected bodies of water, but an interim step that must be followed up with actions to reduce the flow of nutrients into the water.

Little Doubt of Drought

Research on the history of drought in Africa, published in the 27 January 2000 issue of Nature, suggests that a catastrophic drought will occur within the next 50-100 years. The study, led by Dirk Verschuren of the University of Minnesota in Minneapolis and the University of Ghent in Belgium, used sediment samples from Lake Naivasha in Kenya to reconstruct a 1,100-year history of the rainfall in east Africa.

In an 8 February 2000 article in The New York Times, Verschuren said that such a drought could result in drastically decreased agricultural outputs for periods possibly lasting 10-15 years, and would affect an ever-increasing human population--one that has doubled in the last 25 years. Verschuren stressed that the findings show the need for Africans to plan for future megadroughts and reduce their reliance on irrigation-supported agriculture.

A Cleaner River to Run through China

China has begun construction on a large-scale project to reduce the 700 million tons of untreated wastewater annually flowing into the world's third longest river, the Yangtze, and one of its main tributaries, the Jialing. The pollution has contaminated the river valley in Sichuan Province and threatens the environment of the Three Gorges region, a popular tourist area.

The project, which has a scheduled completion date of 2004, consists of a 92-kilometer-long network of underground pipelines that will collect household wastewater and transport it to two processing plants. The World Bank and the Chinese State Development Bank will provide most of the $310 million cost of the initiative, which is being implemented by Chinese state agencies and the Chongqing municipal government.

Going Public with Chemical Information

To promote public understanding of the health and environmental risks associated with high production volume chemicals, basic health and environmental information on over 2,000 such chemicals is being released through the EPA's HPV Chemical Challenge Program.

The program, part of Vice President Al Gore's Chemical Right-to-Know Initiative, makes available to the public screening-level toxicity data on chemicals produced or imported into the United States in amounts exceeding one million pounds per year. The information has been voluntarily provided by 403 chemical manufacturers. The database established through this program will support a screening-level hazard characterization.

Evolving Dangers of E. coli 

According to a report in the September-October 1999 issue of Emerging Infectious Diseases, an estimated half dozen new strains of toxin-secreting E. coli may account for over 55,000 cases of illness per year in the United States. The report states that "the importance of some of these organisms in the United States is seriously underestimated," possibly because the bacteria cannot readily be identified in U.S. laboratories.

Most of the public health focus on E. coli has been on the O157:H7 strain, but outbreaks of the O111 strain, one of which killed a seven-year-old Ohio girl in October 1998, have been turning up in the United States. In a 20 December 1999 Cox News Service article, David Acheson, director of the Food Safety Initiative in Boston, said that U.S. regulatory agencies have not been proactive enough in researching these new bacteria, especially since their adverse health effects have been reported in Canada and other countries. Paul Mead, head of the Centers for Disease Control and Prevention's infectious disease unit and lead author of the Emerging Infectious Diseases report, says that his agency is now developing a clearer sense of the dangers of E. coli strains other than O157:H7.