Such attention to problem sites is long past due, according to Cornell Waste Management Institute Director Ellen Harrison, who notes that Rusin and colleagues fail to address what could be happening at problem sites. Only some sites where treated sludge is applied to land appear to be associated with illness, she says. It might be more productive to specifically examine these locations. “This paper, while interesting, doesn’t appear to address the questions about what’s happening at sites where people are becoming ill,” she says. —REBECCA RENNER
Endocrine disrupter found in aircraft deicer
STEVE CORSI, U.S. GEOLOGICAL SURVEY
With a little bit of detective work and some “reverse engineering”, scientists have discovered what may be contributing to the toxicity of aircraft deicing fluids. In the September 15 issue of ES&T (pp 4031–4037), Steven Corsi of the U.S. Geological Survey (USGS) in Middleton, Wis., and colleagues report finding alkylphenol ethoxylate surfactants in various aircraft deicers and one of their breakdown products, nonylphenol, a known endocrine disrupter, in streams receiving airport runoff. Although the main ingredient in aircraft deicers is either propylene glycol or ethylene glycol, numerous studies have shown toxicological effects of deicer solutions that can-
Nonylphenols have been found in streams that receive airport deicer runoff.
not be attributed to these two chemicals. Manufacturers are reluctant to disclose what kinds of additives are in their deicer formulations, which often include surfactants, corrosion inhibitors, flame retardants, dyes, and foam suppressors. “All of the additives are proprietary, which makes it real difficult for us to determine what is causing the true toxicity,” Corsi says. Using a technique called fast atom bombardment mass spectrometry, coauthor Jennifer Field of Oregon State University screened nine different aircraft deicers for numerous surfactants. Nonylphenol ethoxylates showed up in three of them, and octylphenol ethoxylates showed up in two. Alkylphenol ethoxylates are non-ionic surfactants widely used to reduce surface tension in numerous products, including detergents, paints, pesticides, and now aircraft deicers. The chemicals have been shown to break down during wastewater treatment processes into more toxic alkylphenols, which have estrogenic properties. Even though octylphenol is 10–20 times more estrogenic than nonylphenol,
News Briefs Farmed salmon highin PCBs Seven out of 10 U.S. farm-raised salmon have polychlorinated biphenyl (PCB) levels that exceed U.S. EPA health standards for PCBs in wild fish, according to an independent analysis commissioned by the nonprofit Environmental Working Group (EWG). The tests, which were the first ever conducted on farmed salmon from U.S. grocery stores, suggest that the fish contains more PCBs than any other protein source in the U.S. food supply. Compared with wild salmon, farmed salmon contains an average of 16 times more dioxin-like PCBs, according to the analysis. The U.S. Food and Drug Administration’s store-bought fish standards are 500 times less safe than EPA’s for wild fish, according to EWG. PCBs in Farmed Salmon: Factory Methods, Unnatural Results is available at www.ewg.org/reports/ farmedPCBs.
Extracting commitments Energy and mining companies that do not make clear their commitments to the environment may be risking their businesses, according to Insight Investment, one of the United Kingdom’s largest investment managers. “Growing resource scarcity, increasing development pressures on biodiversity, and escalating public concern mean this issue will present a greater business risk for extractive and utility companies in the future,” says Kerry ten Kate, Insight’s director of investor responsibility. Insight’s research shows that 45% of extractive companies make little or no mention of biodiversity or environmental conservation in their public documents. For more information, go to www. insightinvestment.com.
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NOAA
Institute in Ithaca, N.Y., has compiled a database of about 40 incidents in 15 states that affected more than 300 people, as of February 10, 2003. However, a recent National Research Council committee found no documented evidence that exposure to treated sludge is causing illness. But the committee also found that no government agency has investigated or tracked health complaints (Environ. Sci. Technol. 2001, 35, 338A). EPA has promised to work with the CDC and other public health agencies to remedy this deficiency (Environ. Sci. Technol. 2003, 37, 212A).
Environmental▼News most of the concern has centered around nonylphenol and its parent compounds because they are more abundant in the environment. It is unclear whether airport runoff is likely to be a major source of alkylphenols. In a stream near General Mitchell International Airport in Milwaukee, Wis., the researchers found nonylphenol at a concentration of 3.89 micrograms per liter (µg/L) after an intense aircraft deicing event on January 31, 2002. For comparison, in a recent USGS study, Dana Kolpin and colleagues found nonylphenols in 43 out of 85 U.S. rivers, with a median concentration of 0.8 µg/L and a maximum concentration of 40 µg/L (Environ. Sci. Technol. 2002, 36, 1202–1211). In laboratory studies, nonylphenols have been shown to cause endocrine-disrupting effects in rainbow trout exposed to levels as low as 8.3 µg/L (Environ. Sci. Technol. 2001, 35, 2909–2916). Wastewater treatment plants (WWTPs) are likely to be a much bigger source of alkylphenols, believes Alba Torrents, an associate professor of civil and environmental engineering at the University of Maryland, College Park, who has been investigating nonylphenols in WWTP discharge near Washington, D.C., and Baltimore, Md. “As a
source, WWTPs probably contribute higher loads to the receiving streams, because they operate constantly and discharge large volumes. At airports, deicing occurs only a few times a year, and the amount of runoff, even if concentrated, will not match that of a WWTP effluent,” she says. Nonetheless, biota living in streams near airports are exposed to concentrations of nonylphenols that could be toxic, even if it is for a short period of time, she adds. The U.S. EPA estimates that 21 million gallons of aircraft deicing fluid (50% concentration) are discharged annually into U.S. surface waters, according to a 2000 report. Alkylphenol ethoxylates and their breakdown products add to a growing list of toxic compounds hidden in aircraft deicers. Proprietary additives make up about 1–5% of deicer fluids, according to coauthor Devon Cancilla of Western Washington University, who previously reported finding tolyltriazoles in aircraft deicers (Environ. Sci. Technol. 1998, 32, 3834–3835). Tolyltriazoles are anticorrosion chemicals used extensively in paints, cooling towers, car radiator fluids, and anywhere metal and water are together, Cancilla says. The chemicals are much more toxic to fish
Global climate change is altering the thermal structure and productivity of lakes recovering from acid rain, according to researchers studying lakes in the southern boreal forest of Ontario, Canada. Impacted by climate change and additional stressors, such as calcium depletion and invasive species, the lakes may not all return to their original biological condition, says Bill Keller, a limnologist with the Ontario Ministry of the Environment. Loss of dissolved organic carbon (DOC) is making the lakes clearer, driving photosynthetic production to the lake bottom and warming the water above tolerance thresholds for once-native trout, says John Gunn, a fisheries researcher with the Ontario
ED SNUCINS
Climate change undermines recovering lakes
Some Canadian lakes are too clear for their own good.
Ministry of Natural Resources. Because the lakes exhibit strong thermal responses to small differences in DOC, they have become sensitive indicators of climate change and may also be used to predict future changes in Arctic lakes under a warming climate, he
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and other organisms than glycols. Cancilla and colleagues have detected tolyltriazoles in groundwater near airports and in fish. They are currently investigating their cellular effects in fish. “We know triazoles are in aircraft deicers, but there are a lot of other compounds as well. We still don’t know what they are,” Cancilla adds. “The triazoles can’t account for all of the toxicity that we observe. One of these days, we’d like to come up with more funding to do some more fractionation of the material itself,” he says. “There is the potential for these things to have long-term low-level effects that nobody knows about.” Meanwhile, airports such as General Mitchell International are taking a proactive approach to improve the quality of their discharge, according to the airport’s environmental manager, Greg Failey. Unlike many other airports that use high volumes of aircraft deicers, General Mitchell International is one of the few that is aggressively trying to understand what is causing toxicity in the receiving waters, he says. “We are taking an extra step that a lot of other airports would not in order to understand the actual chemistry of the problem,” he says. —BRITT E. ERICKSON
said at the International Mining and the Environment conference in May. “As lakes recover from acid rain, you would expect them to become more opaque because the DOC that colors the water should increase in concentration as levels of acid and metals, which precipitate DOC, decline,” Gunn explains. Instead, lakes in Killarney Park, south of Sudbury, are becoming some of the clearest in North America, he says. Nellie and O.S.A. Lakes have less than 0.2 milligrams per liter of DOC, and their clarity has increased by 10 meters (m) over the last 30 years to a secchi depth (a clarity measure) of 32 m. Prior to acidification, the lakes probably had a secchi depth of 11–12 m, says Gunn. Two traits of global climate change, declining rainfall and in-
