Government Watch Combustion emissions
Until recently, external sources, such as atmospheric deposition and soil runoff, were thought to play a much more significant role in setting phosphate concentrations. "This paper provides a rigorous analysis of the discrepancy between the chemically measured phosphate and the amount in solution measured using chemical mass balances," says David Lean, who holds the National Science and Engineering Research Council Chair of Ecotoxicology at the University of Ottawa in Canada. Since the late 1950s, limnologists have known that chemically determined values of phosphate were too high, but many monitoring programs continue to measure "phosphate" in this manner. Most scientists just did the best they could with the measurements available, Lean explains.
"The kinetic analysis used here provides valuable insights into phosphorus dynamics in lakes and illustrates that we still have a lot to learn about the limiting nutrient phosphorus and the control of microbial metabolism in fresh waters," Lean says. Hudson and co-workers invented a new method, which is based on steady-state mass balances, to get around the problems of direct chemical measurement of phosphate. They measured the uptake and release of radiolabeled phosphate and used these rates to calculate the concentration of dissolved phosphate. "Our results indicate that these food webs remain incredibly productive with incredibly small amounts of phosphate present," says Hudson. A few previous studies support the low estimates obtained with the steady-state bioassay. —REBECCA RENNER
Scotchgard ban highlights unknowns Fluorinated organic surfactants are in the spotlight following a May decision by chemical manufacturer 3M Corp. to remove Scotchgard, its highly popular stain repellant, and other products that contain the surfactants from the market. One compound used to produce Scotchgard, perfluoro-octane sulfonate (PFOS), led 3M to take this dramatic step after researchers funded by 3M found PFOS in human blood and in animal tissue samples from many parts of the world where it is not manufactured. PFOS has been found to accumulate in birds and mammals, not through fats as other persistent organic compounds do, but through a nonlipid mechanism involving the blood and liver, according to Michigan State University zoologist John Giesy, who has analyzed archived animal tissue samples for 3M. Animal tests also indicate that PFOS causes death in adult monkeys, and rat off-
spring that received high doses of PFOS in utero. Research papers reporting these findings are expected to be published soon. Researchers and regulators worldwide are furiously investigating the environmental fate, transport, and impact of PFOS, as well as many other fluorinated surfactants in use. Questions surrounding these issues currently outweigh the answers. "Fluorine is being introduced into all manner of chemicals at an unprecedented rate," says University of Toronto chemist Scott Mabury, who is one of the few nonindustry scientists studying these compounds, thanks to funding from the Canadian government. "But what we know about fluorine chemicals in the environment is less than what we knew about chlorine chemicals in the 1950s," he warns. The products containing PFOS include coatings for textiles, pa-
To combat acidification, eutrophication, and ground-level ozone, the European Union's (EU) council of environment ministers has agreed on emission limits for large electric power plants. If the EU Parliament approves the June 22 directive as crafted, it would set nationwide emission standards for S02, NO,,, volatile organic compounds, and ammonia (NH3). These standards would be met by 2010, but member countries could set tougher limits. The environment ministers negotiated for a year on this directive because some countries did not want to set emission limits on currently operating plants. But discussions picked up following the suggestion to devise nationwide standards, or national emission ceilings. Under this approach, combined emissions from all power plants in one country must not exceed the emission ceiling. This would make it possible for a country to choose which plants will need to cut air pollution. Plants that produce 50 MW of power or more, including those licensed before the old 1987 EU directive, would have to meet the proposal's limits.
Science at U.S. EPA A high-level science and technology czar, with a six-year tenure, should be installed at the U.S. EPA to keep the regulatory agency from adjusting its science to fit current policy, a committee of the National Research Council (NRC) concludes. In a new report, "Strengthening Science at the U.S. EPA: Research Management and Peer Review Practices", the fourth and final in a series, the committee concedes that its 1995 recommendation to designate the director of Continued on Page 373A
SEPTEMBER 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 3 7 1 A
Environmental News pers, and packaging; chemist. Scientists who fire-fighting foams; and study fluorinated organic other specialty compocompounds say the long nents. Other fluorinated carbon-fluorine chains organic compounds, that form the backbone including sulfonates and of these compounds sulfonamides, are found mean many are likely to in herbicides and be exceedingly persistent pesticides. in the environment. "Some fluoro-organics How PFOS accumuwill redefine persistence lates in animals such as in comparison to PCBs flesh-eating birds from and DDTs, which will remote areas in the Pagenerally be considered cific Ocean is the most labile in comparison," intriguing question, Mabury says. many scientists say, because PFOS is not To study the environmental effects of fluorinated surfactants. UniverThe molecules are so sity of Toronto scientists dose 16 mesocosms—10,000-liter-ponds, im- persistent because long thought to be volatile. itating an aquatic environment with PFOS. At first glance, this fluorinated hydrocarcharacteristic appears bon chains in these surto rule out the type of long-range factants create "molecular rebar", A host of more basic questions atmospheric transport through adds Stanford University chemist also remains. Litde is known about which persistent organic pollutCraig Criddle. The perfluoroalkyl the physico-chemical properties, ants, such as DDT, volatilize in chains are stiff and very difficult such as the vapor pressure or octawarm climates and are carried by for microbes to degrade, he says. nol water partition coefficient, the winds to cooler climates adds Jennifer Field, an Oregon Fluorinated surfactants are where they precipitate. State University environmental likely to exhibit a range of toxici-
LC/MS tool to help military characterize fluorinated surfactants Fluorinated surfactants are part of the groundwater contamination problems that face military bases. The surfactants are constituents of aqueous film-forming foams (AFFFs), used to fight hydrocarbon fuel fires. Although military scientists have suspected that fluorosurfactants were in contaminated groundwater plumes, they could not actually identify the compounds, because no technique existed that could isolate and analyze fluorosurfactants in samples. Scientists Cheryl Moody and Jennifer Field have been grappling with these analytical issues. In the Sept. 15 issue of ES&T, they conclude that "liquid chromatography/mass spectrometry (LC/MS) will most likely
ously, the scientists found perfluorocarboxylate surfactants at the same three bases using gas chromatography/mass spectrometry. The analytical challenge is daunting because commercial AFFF formulations are complex proprietary mixtures whose major components include a solvent, typically a glycol ether, fluorocarbon surfactants, and hydrocarbon-based surfactants. Fluorinated surfactants contribute to the performance of AFFF as the primary fire-extinguishing chemical and as vapor sealants that prevent reignition of fuel and solvents, according to Moody and Field. Groundwater contamination at military bases stems, to a large ex-
The military comprises 75% of the AFFF market in the United States, but the chemical is also used by petrochemical companies, pharmaceutical manufacturers, airports, fire departments, and municipalities throughout the world, says Mitchell Hubert, at AFFF manufacturer Ansul, in Marriette, Wl. Besides contaminating water supplies, AFFF-laden waters can cause problems for wastewater treatment plants because they have high biological and chemical oxygen demands. At high concentrations, the surfactants turn the treatment tanks into a bubble bath, which shuts down the facility, according to Field.
prove to be the most useful tool for characterizing the compositions and concentrations of a range of perfluorinated surfactants in environmental samples." Moody, who is currently at the University of Toronto, and Field, who is at Oregon State University report quantitative identification of perfluoro-octane sulfonate in groundwater from three military bases. Previ-
tent, from fire-training exercises conducted at fire pits. Firefighters light up a cocktail of flammable fuels, then put the fire out with AFFF. The resulting liquids were either sent to a wastewater treatment plant or dumped onto the ground. To reduce contamination, the military is looking at ways to use AFFF substitutes as often as possible in training exercises,
In early August, officials from all branches of the U.S. military met at the Naval Research Laboratory in Washington, DC, to review the environmental impacts of AFFF and draft a department-wide policy on AFFF. The military has evaluated protein-based foams including products that use ox blood, but these have not proven as effective. —R.R.
3 7 2 A • SEPTEMBER 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS
Government Watch ties, says John Trosko, a molecular geneticist at Michigan State University. He and Brian Upham, also of Michigan State, have already identified toxic activity in perfluoro-octanoic acid and perfluorodecanoic acid. In 1998, their published research showed that these compounds block cellto-cell communication and promote tumors. Analyzing fluorinated organic surfactants is a major challenge, says Steven Strauss, a Colorado State University chemist. Chemically, they are nonvolatile and very inert, which makes it difficult to separate or concentrate the compounds for analysis, he explains. Even isolating fluorinated surfactants from environmental samples is complicated because product formulation details are
confidential, says Field. Fluorinated surfactants in environmental samples also can be detected using 19F nuclear magnetic resonance, Mabury says. As part of an Organization for Economic Cooperation and Development initiative aimed at assessing the problem on a global scale, U.S. EPA's chemical control division began a review of production and importation records for new chemicals over the past 20 years, according to Barbara Leczynski, the chemicals branch chief who managed the review. Agency officials are meeting with those from 3M and DuPont, in an effort to promote voluntary action and to explore regulatory options, first for PFOS, then for perfluoro-octanal carboxylic acid. —REBECCA RENNER
NRC urges pesticide alternatives In the push to make food safer for children through bans on many widely used pesticides, farmers could lose their quick-fix methods of handling pest and disease outbreaks. Replacing these conventional chemical pesticides with safer management techniques is addressed in a new National Research Council (NRC) report. The report, The Future Role of Pesticides in U.S. Agriculture, released in July, promotes an ecologi-
Almond and walnut growers in California have eliminated insecticide use by planting cover crops to attract beneficial predators that control mites, worms, and scales.
cally based approach to coping with pests, similar to Integrated Pest Management (IPM). The report recommends government policies and increased research to foster alternatives to chemical pesticides such as natural ecosystem processes, biological control organisms and products, and pestresistant plants. But chemical pesticides, especially new ones, should continue to be used, in the NRC panel's view, because of the reduced environmental and health risks of new pesticides and the lack of affordable alternatives. IPM experts in integrated pest management say this message could have little effect on U.S. farmers, who are the users of pesticides first and foremost and are unlikely to change, given the government's poor track record at promoting alternative pest controls. Nonetheless, a real movement is afoot to switch to more ecologically based methods of pest control, thanks in part to the 1996 Food Quality Protection Act (FQPA), says Ann Sorensen, with American Farmland Trust, a nonprofit organization representing family farms.
EPA's Office of Research and Development (ORD) as the agency's "chief scientific and technical officer" was insufficient. "No single individual could reasonably be expected to direct a worli class research program in ORD while also trying to improve scientific practices and performance throughout the rest of the agency," the committee writes. And because the ORD chief holds the same rank as the regulatory program officers, ORD's advice is routinely ignored by those developing policy. The report strengthens previous panel recommendations designed to enhance EPA's scientific stature and leadership by suggesting that ORD create the equivalent of endowed academic research chairs, to be offered to distinguished academic scientists who would work full-time at ORD national labs. In addition, EPA should no longer allow one individual to both manage a project and serve as its peer review leader, NRC writes.
Recycling computers Efforts to tame Europe's growing mountain of electronic waste took a big step forward in June when the European Commission proposed legislation that for the first time would require manufacturers to recycle obsolete equipment and eliminate certain hazardous materials from products ranging from computers to toasters. Originally drafted as one directive {Environ. Sci. Technol. 1999, 4 (6), 228-229A), the proposal was split to stem industrial opposition to the hazardous materials ban and recycling requirements. As it now stands, one directive would require that 60-80% of electronic waste be recycled by 2006.The other would order manufacturers to substitute less Continued on Page 375k
SEPTEMBER 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 3 7 3 A
