30 years, total emissions of 6 principle air pollutants have decreased by nearly 25%, although more than 133 million people live in areas where monitored air quality in 2001 was unhealthy because of high levels of at least one major air pollutant. Rates of annual wetland losses have decreased from almost 500,000 acres annually in the 1970s to less than 100,000 annually since 1986. But the quality of the wetland losses looks bleak: In key parts of the country, valuable wetlands are still being lost, the report notes. The project was launched in 2001 at the request of former EPA Administrator Christie Whitman, who had led a similar effort as governor of New Jersey (Environ. Sci. Technol. 2002, 36, 265A). The draft can be downloaded at www.epa. gov/indicators. —CATHERINE M. COONEY
News Briefs California city strives for 1 MW of solar power A group of residents in Sebastopol, Calif., have set a goal to bring 1 megawatt of solar energy capacity to city residences, businesses, and municipal buildings by 2005. In late August, local government, advocacy groups, and industry assembled to educate consumers and offer discounted equipment in support of the first-of-its-kind cooperative. Several other towns in California may follow, according to Dan Pelligrini, president and CEO of Cooperative Community Energy, a solar energy group that is supported by the U.S. Department of Energy. For more information, visit www.ccenergy.com/news/ solarsebastopol.html.
Multiple stressors behind Lake Erie decline
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Oxygen-starved zones are appearing in Lake Erie more often and earlier in the season.
Lake bottoms naturally develop hypoxic zones with low levels of oxygen in the summertime, but hypoxic zones have occurred in Lake Erie more often and earlier in the season than they did in the 1980s and the early 1990s, says Jan Ciborowski, an aquatic ecologist at the University of Windsor in
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Lake Erie is exhibiting symptoms of nutrient overload, such as more frequent zones of depleted oxygen and blooms of nuisance algae, even though the amount of the usual culprit, phosphorus, entering the water from sewage plants and runoff has not increased. Early results from a U.S. EPA-funded study hint that invasive species and climate change may lie behind these observations.
Ontario. A research cruise in late August found that 8 out of 10 monitoring stations had oxygen concentrations below the threshold of 4 milligrams per liter, at which aquatic life is threatened with suffocation. Climate change could be accelerating the hypoxia process, says Bob Heath, director of the Water Resources Research Institute at Kent State University. Warmer temperatures have reduced water levels by about four feet compared to the late 1990s, explains Jeff Reutter, director of the federal Ohio Sea Grant Program at Ohio State University. The shallower water is then warmer when the lake stratifies into warm and cold layers in spring, causing bacteria to respire faster and consume more oxygen, Heath says. Because the top layer is always 40–50 feet thick, no matter what the total lake depth, the bottom layer and its supply of oxygen shrink and become more susceptible to anoxia when lake levels drop, Reutter adds. Phosphorous levels are rising in the lake, although scientists don’t know where the extra phosphorus is coming from. Phosphorus inputs have not changed since they de-
Guidance for science and technology policy U.S. congressional leaders are in urgent need of usable science and technology advice, according to a new book edited by Carnegie Mellon University Professors Granger Morgan and John Peha. Science and Technology Advice for Congress points out that congressional members often must make decisions in the face of scientific uncertainty and competing scientific claims from special interest groups. To address this, the authors suggest that decision makers be provided access to careful, balanced, interdisciplinary analysis of issues presented in a nontechnical form. Several combinations of institutions could fill the information gap, but if budgets are constrained, the editors recommend the establishment of at least one analysis organization that works for Congress, similar to the old Office of Technology Assessment, which is directed by a bipartisan committee. The 232-page book is available at www.rffpress.org.
NOVEMBER 1, 2003 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 383 A
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are and extends an open invitation [to others] to provide that data,” he adds. Various government agencies and several states, such as California, Michigan, and South Carolina, collected data for their own indicators programs; however, painting a national picture with these data proves troublesome, says Keith Harrison, chair of the Michigan Environmental Science Board. Most data, with the exception of a few areas such as ambient air quality, are collected on a regional or state scale. To be used nationally, state data must be collected under similar conditions by almost identical techniques in order to be compared. The data also must be collected over time, so they might illustrate a trend, Harrison says. The report shows a mixed bag of results. For example, over the past
Environmental▼News clined from 29,000 metric tons in 1969 to the target of 11,000 by the 1980s, says Dave Dolan, an environmental statistician at the University of Wisconsin–Green Bay. However, in Lake Erie’s western basin, springtime phosphorous levels have increased from below 10 parts per billion (ppb) in 1992 to more than 30 ppb, Ciborowski says. These high phosphorous levels, which are far above the targets, are exacerbating anoxic zones. The phosphorus nourishes excess algal production, which fuels the bacteria, boosting consumption of oxygen. One explanation for the rise is invasive zebra and quagga mussels, both of which are powerful filter
feeders that eat algae and then resuspend algal phosphorus in the form of feces, says Dave Culver, an aquatic ecologist at Ohio State Uni-versity. The recycled phosphorus in mussel feces promotes more algal growth that eventually dies, sinks to the bottom, and consumes oxygen. However, although the mussels increase phosphorus loads by about one-third of the amount delivered by rivers to the central basin, this is not enough to explain all of the increase in phosphorus concentration in Lake Erie, Culver says. Old sewage treatment systems overburdened by rapid population growth may hide loads of phosphorus, speculates Murray Charlton, a
limnologist with the National Water Research Institute of Environment Canada. Another slippery source is raw sewage that bypasses treatment systems during heavy storms and does not get measured, he says. A new mathematical model of Lake Erie will be ready next year and will incorporate all the data and processes discovered by the 27 scientists on EPA’s Lake Erie Trophic Status study, says Joe DePinto, an environmental engineer with Limno-Tech, Inc., a consulting firm. The model will determine how much each of the components, such as climate change and invasive species, drives the low oxygen concentrations, he says. —JANET PELLEY
U.S. PBDE milestones
Andreas Sjödin of the U.S. Centers for Disease Control analyzed pooled blood samples dating back to 1985 for the presence of PBDEs. The samples were collected from people in the southeastern United States from 1985 to 1997 and in 2002, and from Seattle in 1999− 2002. “There is a large variability in our data, but we can conclude that [PBDE levels] are increasing significantly,” he told attendees at the Dioxin 2004 meeting in Boston in late August. The rising PBDE concentrations in U.S. blood samples are especially
noteworthy because the levels of the PBDE congener with the greatest tendency to bioaccumulate, BDE-47, in the samples is higher, on average, than the levels of the most bioaccumulative PCB congener, CB-153, says Sjödin (see graph). Many researchers believe that this is a significant, albeit troubling, milestone. In September, EWG published a report detailing the first nationwide tests of U.S. women’s breast milk, which revealed some of the highest levels of brominated flame retardants found to date. EWG hired AXYS Analytical Services of Sidney, British Columbia, to analyze samples from 20 firsttime mothers for polybrominated diphenyl ethers (PBDEs. The average level of PBDEs in the milk was 159 parts per billion (ppb), 75 times the average found in recent European studies, according to EWG. The highest level of contamination found in the tested milk was 1078 ppb, and the second-highest level was 755 ppb. One of the two most highly exposed women may have been exposed to the PBDEs when she replaced the cushions in her sofa and loveseat with purchased cushions that she trimmed while inside her home to fit the sofa, according to EWG (Environ. Sci. Technol. 2003, 37, 164A–165A).
This fall, more evidence came to light that the U.S. population’s levels of polybrominated diphenyl ether (PBDE) flame retardants are rising rapidly. The compounds are added to plastics and polyurethane foam in furniture, building materials, and electronic appliances, and they have been shown to impair attention, learning, memory, and behavior in laboratory animals, according to the Environmental Working Group (EWG), a nonprofit organization.
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This slide, which was created for ES&T by Andreas Sjödin of the U.S. Centers for Disease Control, shows the levels of the most bioaccumulative PBDE congener, BDE47, and the most bioaccumulative PCB congener, CB-153, in U.S. human blood samples. 384 A ■ ENVIRONMENTAL SCIENCE & TECHNOLOGY / NOVEMBER 1, 2003
