and their distributions could change if calcium drops below critical thresholds, he says. Some of the Sudbury area lakes are close to the threshold, but researchers cannot say when or whether the lakes will cross the threshold, he notes. Invasive species are another stressor that will change the kinds and abundance of native algae and fish, Dillon says. “There are a rapidly growing number of lakes with Bythotrephes cederstroemi, the spiny water flea, which is hard for fish to eat and is a heavy predator on zooplankton,” he says. “The clear lakes in Killarney provide the best long-term signal of climate change,” Gunn says. There are thousands of shallow, clear trout lakes in the Arctic that now stay cold because they are exposed to bright light for only brief periods. But if global warming increases the time during which these lakes are ice-free, they could become sunburned and, like the Killarney lakes, lose the thermal stratification so vital to trout, he says. The change in thermal regime is not limited to the Sudbury area. It controls habitat availability for certain species of algae, zooplankton, and fish, Dillon says. —JANET PELLEY
EPA perchlorate decision takes many by surprise The U.S. EPA announced in July that it would not move forward with developing regulations for any unregulated drinking water contaminants at this time. This decision surprised many in the drinking water arena, particularly because perchlorate, which is the primary ingredient used in manufacturing solid propellant for rockets, missiles, and fireworks, is a high-priority contaminant of concern on EPA’s Contaminant Candidate List (CCL). The list includes 50 chemical and 10 microbial contaminants, and EPA is required under the Safe Drinking Water Act to select at least 5 contaminants from this list every 5 years and determine whether a regulation would likely result in a reduction of health risks.
EPA recommended a preliminary drinking water limit of 1 part per billion (ppb) for perchlorate in 2002 (Environ. Sci. Technol. 2002, 36, 125A), but there are still many unknowns, says John Millett, an EPA spokesperson. He points to ongoing activities such as data collection on occurrence, work to improve low-level detection methods, and reviews of perchlorate removal technologies, all of which will need to be finalized before a standard can be developed. Additionally, the National Academy of Sciences is currently reviewing the risk assessment on which the draft 1-ppb limit is based (Environ. Sci. Technol. 2003, 37, 166A–167A). Environmentalists are concerned, however, that “the effect of EPA’s lat-
News Briefs Good news for GM crops The risks to human health from commercial genetically modified (GM) crop varieties or foods made from them are very low, according to a report commissioned by the U.K. government. Investigators found no evidence to show crops are toxic, allergenic, or nutritionally deleterious. The report, which reviewed all relevant scientific literature, also noted that the three main commercial GM crops—maize, canola, and cotton—are unlikely to be toxic to wildlife, invade the countryside, or become problematic plants. However, the report stressed that the findings were not a blanket approval for GM crops and recommended a case-by-case approach to making environmental impact assessments. An open review of the science is available at www.gmsciencedebate.org.uk/ report/default.htm.
Businesses slacking on climate change Most of America’s biggest greenhouse gas-emitting companies are still pursuing business strategies that fail to respond adequately to the potential impacts of global warming, finds a report by the Coalition for Environmentally Responsible Economies (CERES), composed of environmental, investor, and public interest groups. In contrast, non-U.S. companies are more likely to report on the financial risks of climate change and undertake mitigation strategies. The report profiles 20 companies and finds that most of their securities filings do not disclose the financial risks associated with emissions. The electric power industry scored lowest. Those that scored highest include oil companies BP and Royal Dutch/Shell. Corporate Governance and Climate Change: Making the Connection is at www.ceres.org.
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creasing evaporation, mean that fewer organics are washed into lakes and water doesn’t spill as quickly out of the lakes, leaving DOC exposed to sunlight for longer periods, Gunn says. The ultraviolet portion of sunlight breaks down the DOC, eventually oxidizing it to carbon dioxide and making the lakes a net source of greenhouse gases, says Peter Dillon, a biogeochemist at Trent University in Canada. Whereas photosynthesis was once carried out mainly by suspended algae in the upper water layers, light now penetrates to the bottom of the “sunburned” lakes in Killarney, stimulating lush aquatic moss growth as deep as 50 m below the surface, Gunn says. In the 1940s, the cool dark lake depths sheltered cold-loving trout. Killed off by acid rain, trout would find today’s lakes too warm to live in, as dark bottom sediments not covered by moss soak up the sun’s rays and elevate temperatures of the deep waters to 13–15 °C. Acid rain has depleted the calcium pool in watershed soils, and this continues to be a problem even as lakes become less acidic, Keller adds. Crayfish, other crustaceans, and daphnia (a group of water fleas) all depend on calcium,
Environmental▼News est decision will be to kick perchlorate and everything else into the next five-year cycle, which means it’s very unlikely that they’re going to get around to regulating these things for about a decade,” says Erik Olson, a senior attorney with the environmental group Natural Resources Defense Council. “If EPA can’t decide that a regulation is needed for a chemical like perchlorate, which is contaminating the drinking water of 20 million people and is at levels above what EPA’s risk assessment says are safe, I think it’s a stunning admission that the agency’s process has broken down.” Indeed, EPA has confirmed perchlorate releases in groundwater and surface waters in at least 20 states. Contamination is particularly extensive in California, and the state is moving forward with a drinking water standard “because we have a problem here, and we need to deal with it,” says Robert Miller, a spokesperson for the state’s Department of Health Services (DHS). California’s legislature set
a deadline of January 2004 for the standard, but a lawsuit by two aerospace corporations has slowed the process. DHS officials hope to establish a public health goal by this fall and a standard soon afterwards. David Spath, chief of DHS’ Division of Drinking Water and Environmental Management, said at a perchlorate symposium in Sacramento in late July that the state would likely adopt a standard by emergency regulation in order to meet the January deadline. The state’s draft goal is currently set in a range of 2–6 ppb. In EPA’s defense, Millett says that the agency is not precluded from taking actions on CCL contaminants before the end of the next regulatory determination cycle, which is August 2006, if information becomes available beforehand. In fact, he notes that “EPA feels fairly confident that we will be able to make a sound regulatory determination one way or the other on perchlorate by this time next year.” State drinking water officials and utilities say that they’ll be closely
EPA strengthens some drinking water protections The U.S. EPA proposed two new drinking water rules in July that seek to balance the risk trade-offs associated with the need for increased protection from microbial contaminants (Cryptosporidium in particular) and reduced levels of disinfection byproducts (DBPs). Cancer and adverse reproductive and developmental effects have been linked to DBPs in treated drinking water (Environ. Sci. Technol. 2002, 36, 198A–205A). EPA officials say that the rules were introduced simultaneously, because, generally speaking, treatment aimed at killing Cryptosporidium can generate increased levels of DBPs. Both proposals build on rules already in effect (Environ. Sci. Technol. 1999, 33, 113A–114A). State drinking water officials and water suppliers voice cautious support for the new provisions, but note they are still analyzing the rules, both of which are several hundred pages long. Environmen-
talists criticize the DBP rule for allowing states to decide case by case on what actions to take if a water utility exceeds the maximum contaminant levels (MCLs) set for DBPs. This approach mirrors the direction EPA seems to be taking in its rules—to allow states to make decisions rather than set national requirements. The previous DBP rule reduced exposure to several DBPs, including trihalomethanes, haloacetic acids, chlorite, and bromate, which form when disinfectants added to reduce microbe levels react with organic and inorganic materials present in source waters. The new proposal is aimed at the elevated DBP levels that sometimes occur at some points even when the system-wide average is below the MCL. This Stage 2 DBP proposal would expand monitoring requirements to reduce these elevated concentrations, with utilities identifying the points in their water pipelines where the highest
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tracking EPA’s progress on this front and want to see EPA complete its studies before a standard is set. “Perchlorate, in particular, is one we have to make sure we get right,” says Jim Taft, executive director of the Association of State Drinking Water Administrators and former chief of the targeting and analysis branch of EPA’s Office of Ground Water and Drinking Water. “It’s important that there be good, strong scientific information upon which there’s a fair amount of consensus.” Currently, Taft notes, there are still questions about the severity of the health effects of this contaminant at various concentrations in drinking water. Meanwhile, EPA did finalize decisions for nine of the CCL contaminants, determining that no regulatory action is “appropriate or necessary” at this time. The agency expects to publish an updated CCL in late fall, according to Millett. For more information, go to www.epa. gov/safewater/ccl/cclregdetermine. html. —KRIS CHRISTEN
DBP concentrations occur. Utilities would then have to meet MCLs at each of these sites, as opposed to the current approach, which allows elevated DBP levels to occur regularly at some locations in the pipeline system, as long as the system-wide average is below the MCL. Utilities that experience shortterm peaks would be required to review their operational practices and work with the state to determine actions to prevent future occurrences, says John Millett, an EPA spokesperson. But Erik Olson, a senior attorney with the Natural Resources Defense Council, says, “By throwing everything into the lap of the states, we think very little is going to happen. If states wanted to do something, they could do it now, and they’re not.” Under the new microbial proposal, known as the Long Term 2 Enhanced Surface Water Treatment Rule (LT2), utilities would have to step up monitoring for Cryptosporidium, a widespread waterborne pathogen that causes gastrointesti-
