wild chinook inhabit must also play a role, the scientists interviewed for this article agree. Compared with PBDE levels in other fish, the levels in salmon found in the Hites study are low, according to Salmon of the Americas, an industry group. They claim that the total intake of PBDEs from farmed salmon is only a fraction of that from other foods. Hites and his colleagues suggest that it is “prudent” to consume salmon to avoid the higher levels of contaminants found in salmon. They point out that PBDEs are endocrine disrupters that have been shown to have reproductive toxicity. —KELLYN BETTS
A nationwide census of airborne bacteria
CDC
Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Lab (LBNL) are using microarrays to compile a national database of airborne bacteria, which could be a boon for environmental researchers. Immediately after the September 11 attacks, American security officials began planning for a possible chemical or biological attack, and the Department of Homeland Security set up detection systems in major cities. But the detectors have to be calibrated to ignore background noise or, in the case of a biological attack, ambient airborne bacteria.
Environmental scientists should benefit from an ongoing U.S. national survey of ambient airborne bacteria, which has measured background levels of Actinomyces and other microbes.
“The problem is that we really had to create the technology to do this,” says Gary Andersen of the Center for Environmental Biotechnology at LBNL in Berkeley, Ca. “Nobody else has ever done this before.” Created with the aid of gene-chip company Affymetrix, the current generation microarray chip now holds 500,000 probes for over 9000 taxa. “You end up with a table of what’s present and their relative abundance,” says LBNL research associate Todd DeSantis. “So you can see from the sample when a taxa is declining or if it’s on the rise.” This is the first work that shows microarrays can detect not just the presence but also the quantity of taxa. The findings will be published in the journal Environmental Microbiology. The microarray chips uses 25 DNA-base long probes to bind selected sections of 16s ribosomal DNA. The ribosomal DNA is probed because it has sufficient variability to serve as a marker of biological taxa. DeSantis says designing the first chip for broad environmental
News Briefs U.S. fish advisories increase The number of state-issued fish advisories is on the rise, according to the U.S. EPA’s 12th Annual National Listing of Fish Advisories. State agencies issue fish advisories for water bodies as a warning that elevated levels of toxic chemicals, such as mercury or dioxin, have been found in local fish. Since 2002, the number of lake acres under an advisory increased by 2%, river miles increased by 9%, and coastline by 4%. A large part of the increase in lake acres and river miles occurred because Montana and Washington issued statewide advisories for all of their lakes and rivers in 2003; Hawaii issued a statewide advisory for its entire coastline. EPA Administrator Mike Leavitt notes that advisories grew even as emissions for a number of pollutants dropped. For more on the fish advisories, go to www. epa.gov/waterscience/fish.
More bad air days Warmer temperatures caused by global climate change will speed the formation of ground-level smog and increase the number of “red alert” days when people with asthma, children, and older Americans are advised to stay indoors, a new report concludes. By mid-century, individuals living in 15 cities in the eastern United States will see a doubling of red alert days from 2 to 4 per summer. These conclusions are expressed in a report penned by the environmental group Natural Resources Defense Council and are supported by new, unpublished research conducted by Jonathan Patz of the University of Wisconsin–Madison and Johns Hopkins University, Patrick Kinney of Columbia University, and others. Heat Advisory: How Global Warming Causes More Bad Air Days is available at www.nrdc.org.
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PHOTODISC
North Atlantic, which are relatively contaminated. However, he acknowledges that this does not explain why the PBDE levels in farmed European salmon are higher. Researchers are also at a loss to explain why wild chinook salmon from British Columbia had the highest levels of contamination of any salmon Hites tested. They posit that it has to do with the adult chinook’s tendency to feed higher in the food web, eating mainly fish, unlike other salmon species that tend to consume more invertebrates and plankton. Because wild Alaskan chinook tested in the study contained significantly lower PBDE levels, the relative contamination of the waters that the
Environmental▼News sampling was difficult, because microarrays were developed for geneexpression work. “We initially wanted to handle this with off-the-shelf technology, using microarray techniques for expression analysis,” he says. “We found that this just wasn’t working.” After almost two years of work, the lab has already evaluated thousands of samples and is now awash in data. The researchers now have to figure out what to do with it all. DeSantis says they have just enlisted the help of a statistician and are building a website so that scientists can ask questions with different parameters. For instance, a wildlife biologist in Louisiana studying avian disease might want to identify which bacteria are present in the local environment, while an epide-
miologist at a hospital in Minnesota might want to know the seasonal fluctuations of pathogenic bacteria in a nearby city. “We’re just squirreling away a lot of data and trying to put together an ftp site so that people can select cities and download information,” he says. The LBNL researchers recently analyzed data collected during the summer of 2003 from two cities in Texas. Separated by only 80 miles, Austin and San Antonio show some significant differences in their bacterial biota. Both cities have airborne bacteria from the genera Pirellula, Pseudomonas, Rickettsia, Clostridium, and Bacillus. But San Antonio has a much greater diversity of bacteria and also supports Denitrovibrio, Legionella, and Acti-
nomyces. It is not known why two cities so close geographically differ so dramatically in their bacteria. “There must be some local reservoirs for the bacteria,” speculates Andersen. “We’re looking at weather patterns to see if that might explain it.” Although the sampling phase of the project will end in the summer of 2005, analysis of the data could take years. In the future, the research might be expanded, according to Pete Pesenti, a project officer with the Science and Technology Directorate at the Department of Homeland Security. “We’ll take a look at the project next year and then decide if we might need to look at other things in the air like viruses and fungi,” he says. —PAUL D. THACKER
U.K. to tackle endocrine disrupters in wastewater ethinylestradiol, which are excreted from women either naturally or as a result of taking medicines such as the contraceptive pill or hormonereplacement therapy. PHOTODISC
England and Wales are likely to become the first places in the world to actively remove endocrine-disrupting chemicals from their sewage. The Environment Agency of England and Wales has proposed a £40 million demonstration project to assess how estrogenic substances can be prevented from entering sewage effluent or can be removed from effluent. The effort follows a report released in July that finds that sexual disruption in fish is widespread throughout rivers in England and Wales (Environ. Sci. Technol. 2003, 37, 331A–336A). “We know fish are affected, and the source is sewage effluent,” says Geoff Brighty, the science manager of the Environment Agency’s ecosystems section. “We now have enough data to act as a policy trigger for taking action. But what we need to do to sewage treatment to remove these chemicals is not well understood and potentially very costly. We now need water companies to evaluate the potential for sewage treatment to remove these substances.” The most significant substances were the natural steroid hormones 17-estradiol and estrone and the synthetic hormone
Responding to reports of sexual disruption in fish, England and Wales hope to strip estrogenic compounds out of their wastewater.
The agency is working with water companies and advocating the construction at two sites of fullscale demonstration projects that will use enhanced granular-activated-carbon treatment. The proposal also calls for 17 smaller projects in which existing treatment options will be monitored. “This would be ground-breaking and could result in a step change in sewage effluent treatment,” says Brighty. “Treatment would be applied to achieve environmental benefits, not to meet
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specific standards or regulations. Applying drinking-water treatment technology to effluents put back into rivers for environmental purposes has never been done before.” Zoologist Louis Guillette of the University of Florida agrees that enough data now exist to warrant action of some kind. “[The report] now shows categorically for the first time that the [endocrine-disruption] phenomena is widespread, not just isolated to a few rivers or species or sewage treatment facilities,” he adds. “It is the definitive work in this field.” However, he is optimistic that the endocrine disruptors can be treated. “It should take a couple of years for demonstration projects to tell us what we need to know. But fish could start feeling the benefits of any removal technology after three or four years,” he says. However, Thomas Ternes at the Bundesanstalt für Gewässerkunde in Koblenz, Germany, points out that although the activated-carbon technology removes endocrine disrupters very efficiently, it is an extremely expensive option for wastewater treatment because the carbon needs to be replaced regularly. He favors ozonation techniques instead. “We found in two pilot ozone trials that this technique removed 99% of estrogens,” he reports.
