News Briefs
its. U.S. federal law requires that all hazardous waste be properly disposed of in regulated landfills. But Congress exempted mining-industry wastes from hazardous landfill disposal laws by means of a 1980 loophole called the Bevill exemption, which allows mining companies to dispose of waste by turning it into a useful product—in this case, fertilizer. —REBECCA RENNER
Curbing toxic pollution
Neglected forms of phosphorus play important role search presented in August at the Ecological Society of America (ESA) meeting in Portland. The new work is challenging conventional wisdom about nutrient limitation in coastal estuaries, the open ocean, and threatened ecosystems, such as Florida’s Everglades, experts say. Mining of phosphate rock for fertilizer has accelerated the global phosphorus cycle, leading to a 75% increase in phosphorus storage in land and freshwater ecosystems, says P. V. Sundareshwar, a biogeo-
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Balance or bias?
P. V. SUNDARESHWAR
During the past 30 years, most studies of phosphorus—the nutrient that fuels nuisance algal blooms in lakes—have focused exclusively on forms of soluble, reactive phosphorus thought to be most important to biological systems. But a more detailed look reveals that other forms of soluble phosphorus, which are hard to measure, constitute 50–100% of the phosphorus pool in some ecosystems and are more readily bioavailable than previously believed, according to re-
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Scientists are using 31P nuclear magnetic resonance (NMR) spectroscopy to take a closer look at forms of phosphorus that can play a significant role in coastal ecosystems. They are finding that some forms, such as the pyrophosphate shown in this NMR spectrum (which is used in fertilizers and industrial processes), are biologically available.
The European Commission (EC) is calling for nine additional chemicals to be eliminated under two international treaties on persistent organic pollutants (POPs). The list includes four insecticides and industrial chemicals (chlordecone, hexachlorocyclohexane, hexachlorobutadiene, and pentachlorobenzene); three flame retardants (hexabromobiphenyl, octabromodiphenyl ether, and pentabromodiphenyl ether); polychlorinated naphthalenes, which are used for cable insulation and wood preservation; and shortchained chlorinated paraffins, which are used in metal-working fluids. The EC wants to push for a global ban under the 2001 Stockholm Convention on POPs and the 1998 POPs Protocol to the Convention on Long-Range Transboundary Air Pollution. For more information, go to http://europa.eu.int/comm/environment/ pops/index_en.htm.
By following the time-honored journalistic formula for balanced reporting, reporters and editors at four top U.S. newspapers misrepresented the scientific community’s understanding of human contributions to global warming, according to an analysis published in the journal Global Environmental Change (2004, 14, 125–136). “The continuous juggling act journalists engage in often mitigates against meaningful, accurate, and urgent coverage of the issue of global warming,” write the researchers. From 1988 to 2002, a total of 3543 articles on climate change appeared in the Los Angeles Times, The New York Times, The Wall Street Journal, and The Washington Post. The researchers analyzed 636 articles. They discovered that 52.7% gave “roughly equal attention” to generally accepted scientific evidence and to skeptics’ arguments.
OCTOBER 15, 2004 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 383A
RHONDA SAUNDERS
The presence of these trace metals has led some state governments, including those of Washington and Minnesota, to investigate potential safety and environmental concerns associated with Ironite, and EPA is soon to finish its two-year-long risk assessment. Canada limits toxic metals in fertilizers, and Washington, California, Texas, and Minnesota are among the U.S. states that set lim-
Environmental▼News chemist at the South Dakota School of Mines and Technology and lead author on the new research. Previous studies have looked at total phosphorus and one of its components, soluble, reactive phosphorus, but have not focused on the dozen or more phosphorus-containing compounds that make up what has been labeled “soluble, unreactive phosphorus”. Termed “unreactive” because they don’t react in standard techniques used to measure phosphorus, such as the molybdate blue reaction, these forms of soluble phosphorus include polyphosphates, inositol phosphates, and phosphorus sorbed to mineral or organic compounds. These compounds have been neglected because many have been thought to be biologically unavailable and some are difficult to measure, Sundareshwar says. But new applications of techniques such as 31P nuclear magnetic resonance (NMR) spectroscopy are allowing a finer characterization of this fraction of the phosphorus pool, he says. Sundareshwar has used 31P NMR analysis to show for the first time that pyrophosphate (P2O47 –) can constitute more than 50% of the phosphorus in some coastal estuarine sediments. He demonstrated that soil microorganisms readily used the pyrophosphate and that its accumulation in coastal zones was directly related to human activities, such as industrial use and
fertilizer runoff. This finding is important because in some coastal zones, phosphorus availability can limit the growth of the bacterial community. “Our results suggest that the full extent of bioavailable phosphorus accumulation in estuaries is unknown because of the presence of pyrophosphate,” Sundareshwar says. Although plants in estuaries are limited by nitrogen, phosphorus is important because it can lead to bacterial overgrowth and zones of low oxygen, even in the absence of nitrogen-driven algal blooms, he says. This means that resource managers must abandon their current focus on nitrogen alone and work to curb both nitrogen and phosphorus inputs, he adds. NMR analysis of phosphorus is helping to determine why the treatment-engineered wetlands— designed to cut phosphorus in agricultural runoff down to safe levels before it enters the Everglades—are not meeting their target of 10 ppm total phosphorus, says Curt Richardson, director of the Duke University Wetland Center and a coauthor of the research presented at the ESA meeting. It turns out that the bacteria, algae, and plants in the wetlands convert the soluble, reactive phosphorus from fertilizers into dissolved organic phosphorus, which has been overlooked because it was considered an unreactive form of phospho-
Eutrophication implicated in deformed frogs The dramatic rise in the number of frog deformities can be traced, in part, to an increase in the eutrophication of waters where tadpoles hatch and metamorphose into frogs, according to ecologists Pieter Johnson at the University of Wisconsin, Madison, and Jonathan Chase at Washington University in St. Louis. Since the mid-1990s, when reports of frogs with extra, missing, or truncated limbs began to accumulate, researchers have considered excess exposure to contaminants, ultraviolet radiation, and parasites
as the most likely culprits. Previous work from Johnson’s group has linked the deformities to the presence of a parasitic trematode. Now, Johnson and Chase provide persuasive evidence that connects the prevalence of the parasite to the growing number of ponds swamped by nutrients, which may explain why the incidence of deformities has increased to more than 90% in some frog populations. The new work was published in July (Ecol. Lett. 2004, 7, 521–526). “Johnson and Chase present a
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rus, he says. Although it is biologically available, it is not taken up right away and stays suspended in the treated water as it flows into the Everglades. “Because it is not particulate, it doesn’t drop out of the water column onto the sediment. And because it is not orthophosphate, it is not taken up right away so it just flows out of the treatment wetlands,” he says. “The wetland designers didn’t count on the dissolved organic phosphorus not coming out and they will be lucky if they can get the total phosphorus levels down to 15–20 ppm,” he says. On the other side of the globe, changes in ocean mixing over the past decade due to strong El Niño weather patterns have led to a 70% decline in soluble, reactive phosphorus concentrations in the ocean off Hawaii, says Dave Karl, biological oceanographer at the University of Hawaii. Characterization of soluble unreactive phosphorus, which now makes up more than 90% of the phosphorus in the ocean, has helped researchers track how algae are now using it more than the disappearing soluble, reactive phosphorus. This has caused the algae community to shift toward a higher proportion of the less-edible bluegreen algae, he says. New applications for 31P NMR analysis of soluble unreactive phosphorus, including its use as an indicator of ecosystem health and restoration, are in the pipeline, Richardson adds. —JANET PELLEY
convincing argument supporting the eutrophication idea,” says zoologist Andrew Blaustein at Oregon State University in Corvallis. “I really believe that is the correct direction for looking at one of the ultimate major causes for amphibian deformities,” he adds. Others remain skeptical about eutrophication and parasites as the main explanation for frog deformities. “The bulk of reported deformities in the wild are truncations and deletions,” says David Skelly. “This doesn’t match the pattern of parasite infection, which is characterized by a high proportion of extra limbs,” adds the Yale ecologist who
