ES&T's Best Papers of 2005 - Environmental Science & Technology

C&EN's Year in Chemistry. Research of the year C&EN's most popular stories of the year Molecules of the year Science that delighted... SCIENCE ...
0 downloads 0 Views 454KB Size
ES&T’s Best Papers of 2005


n 2005, ES&T published 1288 papers on a broad range of topics. But which ones were the top papers—the best of the year? For the past two years, the editors and the members of the editorial advisory board (EAB) have struggled with how to recognize our top papers. Because of the diverse range of topics, it is a difficult task (akin to choosing between oranges and apples). In the end, our associate editors and EAB members decided they would nominate papers in three categories: environmental science, technology, and policy. As Editor-in-Chief, I read all the nominated papers, considered their usage (downloads) by scientists and reporters around the world, and evaluated their technical quality and potential to make a lasting contribution to the field. It is one of the great and solemn privileges of being Editor that I get to choose the best papers of the year and the runners-up. We hope this is a way to bring special recognition to you, our authors, and focus attention on your high-quality papers. The Best Paper Awards will be an annual event to be announced in February or March of the succeeding year. Each author receives a certificate of award, and our staff writers will produce a brief story highlighting the paper. I congratulate the authors of the 2005 ES&T best papers. —Jerald L. SchnooR

ENVIRONMENTAL SCIENCE Top paper: The perchlorate surprise “The Origin of Naturally Occurring Perchlorate: The Role of Atmospheric Processes” by Purnendu K. Dasgupta, P. Kalyani Martinelango, W. Andrew Jackson, Todd A. Anderson, Kang Tian, Richard W. Tock, and Srinath Rajagopalan, Texas Tech University, 2005, 39 (6), 1569–1575. It began with a phone call in 2003 from the Texas Commission on Environmental Quality. The commission was investigating a case of perchlorate contamination in West Texas groundwater: Could Texas Tech University (TTU) help out? W. Andrew Jackson, an associate professor in the department of civil and environmental engineering, fielded the call and said yes. But the staff soon ran into a problem with the samples that they were collecting. The U.S. EPA’s method for measuring perchlorate in drinking water was not sensitive enough for some of the highsalinity Texas groundwater samples. Kang Tian, a 2086 n Environmental Science & Technology / april 1, 2006

staff scientist with TTU’s Institute of Environmental and Human Health, who had been charged with the analysis, turned to his Ph.D. mentor, Purnendu K. “Sandy” Dasgupta in the department of chemistry and biochemistry. With the help of Todd A. Anderson, an associate professor at the institute, the two developed a better method for perchlorate analysis that delivered the results they needed. Meanwhile, TTU researchers were discovering that the perchlorate contamination was spread over almost 60,000 mi2. Where was it all coming from? This is an arid region with no munitions plants producing perchlorate-containing explosives. Jackson considered the possibility of perchlorate-laced fertilizer, but even the most generous calculations couldn’t account for the contamination levels through an entire aquifer. “From that work, we realized that we couldn’t come up with a reasonable anthropogenic source of perchlorate,” recalls Jackson. However, the area had been irrigated since the 1940s; could the perchlorate have had a natural source? The discussions included Richard W. Tock, currently an emeritus professor. Tock, whom Dasgupta describes as an “indomitable spirit”, decided to conduct the ultimate quick-and-dirty experiment. © 2006 American Chemical Society

First runner-up: Sucking up data with the Big Shark

“Polybrominated Diphenyl Ethers in House Dust and Clothes Dryer Lint” by Heather M. Stapleton, Nathan G. Dodder, Michele M. Schantz, and Stephen A. Wise, U.S. National Institute of Standards and Technology; and John H. Offenberg, U.S. Environmental Protection Agency, 2005, 39 (4), 925–931. In the fall of 2003, Heather M. Stapleton was vacuuming her apartment in a Maryland suburb of Washington, D.C., when it dawned on her that—in addition to her pet rabbit’s fur, her long blond hairs, and the other dust and dirt—her vacuum could be sucking up polybrominated diphenyl ethers (PBDEs). These compounds, which are widely used as flame retardants in household products, are suspected to be endocrine disrupters. As a postdoctoral researcher at the U.S. National Institute of Standards and Technology (NIST) who had been researching PBDEs for 3 years, she was in an ideal position to analyze her own home’s dust. When testing revealed

Jason V. Doyle and purnendu k . dasgupta

Filling a 5-gal plastic bucket with seawater, he hiked over to TTU’s Center for Pulsed Power and Power Electronics and zapped the sample with a 10-GJ bolt of lightning. “There was a sound like a cannon going off, and the water jumped,” laughs Jackson. “It is questionable whether anything happened [other] than a big bang, but it encouraged us to look at [the effect of lightning on common chlorine compounds] in depth.” The researchers began more controlled experiments with spark plugs used as a safer and quieter source of lightning. With data coming in that supported the idea of naturally occurring perchorate, which is the basis of the award-winning ES&T article, the researchers began to consider the implications. “Perchlorate is an iodide transport inhibitor,” points out Dasgupta. “Does perchlorate at environmentally meaningful exposure levels inhibit iodide transport?” In two additional papers in ES&T, Dasgupta and his colleagues have shown that perchlorate is in Texas cow’s milk and, more dramatically, in human breast milk. Meanwhile, the search for naturally occurring perchlorate in the environment continues. “We find perchlorate in pretty much everything,” says P. Kal­ yani Martinelango, who is finishing up her Ph.D. under Dasgupta. The TTU researchers have, with the help of now-Ph.D. Srinath Rajagopalan, measured perchlorate at parts-per-trillion levels in precipitation, in the ocean, and at locations as diverse as Greenland, Hawaii, and Alaska. Moreover, the TTU researchers are finding that

Artificial lightning: P. Kalyani Martinelango adjusts the spark length before running NaCl aerosol through an electrical discharge.

arid regions are storehouses of perchlorate and probably bromate. “These unsaturated zones have been understudied, and with urbanization and land-use changes and possibly climate change, the effect on groundwater is going to be more important,” adds Jackson. “These overlooked species are going to gain importance in the future for long-term cycling and water quality.” With so many new avenues of research, it is not surprising that Dasgupta advocates that more environmental studies of perchlorate are needed. Citing arsenic in groundwater, he warns, “Being natural doesn’t make it good.” —ALAN NEWMAN

that her home had “really high” concentrations of the compounds, the project that led to this top 2005 ES&T publication was born. Stapleton’s next step was to purchase a vacuum suitable for the project. She found her ideal tool at a home improvement store: a silver-gray-colored commercial vacuum called the “Big Shark”, which is about the size of an American football. Besides being portable, its main appeal as a collecting tool was “that it was easy to use, disassemble, and clean between each use, and didn’t have a lot of components that could potentially contaminate the sample,” Stapleton says. Thus equipped, Stapleton began collecting dust samples from friends and colleagues in the Washington, D.C., area. “The big surprise was that the concentrations, on average, that we found were similar to the concentrations you find in sewage sludge and biosolids,” she recalls. She also found higher-than-expected concentrations of the relatively large PBDE compounds associated with the Deca flame retardant formulation in some of the 17 homes she tested. In 2003, Stapleton “didn’t know anyone who had april 1, 2006 / Environmental Science & Technology n 2087

kirk gillis

actually looked [for PBDEs in] house dust.” A literature search revealed that Wilhelm Knoth from Germany’s Federal Environmental Agency in Langen had studied levels in European homes, but—in keeping with the much lower body burdens being found in Euro-

Heather Stapleton’s Big Shark vacuum was an important research tool.

peans—the levels were an order of magnitude lower than those Stapleton was finding. While she and her colleagues were analyzing their data, other reports of PBDEs in U.S. house dust began to come out. But their study was ultimately one of the earliest to be published in the peer-reviewed literature. It was the first to

Second runner-up: Modeling metal munching “Why is Metal Bioaccumulation So Variable? Biodynamics as a Unifying Concept” by Samuel N. Luoma, U.S. Geological Survey, and Philip S. Rainbow, the Natural History Museum (U.K.), 2005, 37 (7), 1921–1931. This runner-up ES&T environmental science paper of 2005—a critical review—was more than 10 years in the making. Two biologists, working independently, began asking questions that weren’t answered by the prevailing theory of toxic metal bioaccumulation. Most importantly, they wondered why a barnacle takes up as much as 100× more zinc than a mussel living in the nearby muck. Decades of research, mostly by geochemists, had linked metal bioaccumulation in aquatic animals to concentrations of dissolved metal ions. Even ecotoxicology experiments by biologists, primarily chronic exposure studies, supported this view. “You put animals under very high concentrations [of metals] and watched them die,” says Philip S. Rainbow of the department of zoology at the Natural History Museum in London. “So, [researchers] automatically assumed everything [that is important] is in water.” And at those unnaturally high concentrations, they were right, adds Samuel N. Luoma, who is with the U.S. Geological Survey in Menlo Park, Calif., and is 2088 n Environmental Science & Technology / april 1, 2006

report PBDEs in dryer lint as a means of determining how the compounds were getting into dust. Stapleton is quick to acknowledge that the timing of the paper’s publication played a big role in its popularity. The paper was published at a time when it was becoming clear that PBDEs were different than most other persistent organic pollutants (POPs) in that exposure from diet alone could not account for the high levels that some people—particularly in North America—were taking up. Indoor air and dust became the most likely suspects. Stapleton and her colleagues also did some research into how people are exposed to PBDEs from dust. Coauthor Nathan G. Dodder of NIST played a key role in these calculations. Ultimately, the researchers collaboratively determined that because toddlers aged 1–4 generally eat quite a bit more dust than the adult population, they get a much higher dose of PBDEs—120 to 6000 ng/day, on average, according to their calculations. In this respect, PBDEs are similar to lead, Stapleton points out. Stapleton is now on staff at Duke University’s Nicholas School of the Environment and Earth Sciences, where she is focusing on another research interest: whether the compounds in dust associated with the Deca formulation are breaking down to create smaller and potentially more toxic compounds, such as the ones associated with PBDE formulations that have been discontinued or banned. In the coming months, she hopes to investigate what happens when dust containing these Deca compounds is exposed to sunlight. —KELLYN S. BETTS

the paper’s corresponding author. However, Luoma and Rainbow are field biologists—as comfortable digging in the mud as working in the lab—and they saw exposure as more complex. “A small school of thought believed that diet was important, but they couldn’t quantify it,” recalls Luoma. “So, the field went ahead with the assumption that only solution was important.” At that time, Rainbow was investigating patterns of bioaccumulation in invertebrates—barnacles, shrimp, and crabs. He and others demonstrated that two species living side by side in the same ecosystems could have metal concentrations that varied by as much as 2 orders of magnitude. For example, one of his papers reported that barnacles living in Poland’s Gulf of Gdansk bioaccumulate 40–100× more zinc than neighboring mussels. Meanwhile, working with Nicholas Fisher at the State University of New York at Stony Brook in the 1990s, Luoma attacked the question of diet. “We decided to break [the problem of diet] apart to its component pieces, in terms of its physiology, and look at bioaccumulation from diet using physiological constants,” he says. Luoma and his colleagues then sewed the pieces back together into a “dynamic, multipathway bioaccumulation model.” “What is important is the differences in the chemistries of the metals, the environmental conditions, and the different ways in which [animals] handle the metal

ke vin brix

under different conditions,” explains Luoma. In effect, the biodynamic model they developed predicts that some organisms can eliminate certain metals quickly and will be less likely to be affected by their presence in water. Other creatures are quick to take up metals but slow to get rid of them and will show higher bioaccumulation values.

Samuel Luoma (left) and Philip Rainbow collect polychaete worms at low tide from the mud in Restronguet Creek estuary in the county of Cornwall (U.K.).

By 2004, when Luoma arrived in London as a Fulbright scholar to work with Rainbow on a book about aquatic contamination, several groups were using the biodynamics model to understand bioaccumulation. Rainbow suggested that they also collaborate on a paper that reviewed progress with the model. “We realized that the two of us knew lots of the literature in which folks had used the model and compared the results to field measurements,” says Luoma, “but it was scattered throughout the literature.”

Together, they identified 15 publications that matched model predictions with field data for 14 species of animals living in 11 different ecosystems. What would become the top ES&T paper covered 7 metals. “We synthesized it all and saw a nice fit over 7 orders of magnitude,” says Luoma. The model does have its limits. Bioaccumulation in animals higher on the food chain, such as fish and birds, requires a more complicated pharmacokinetic model that tackles metal flux among internal organs. But diet is also important to these predators, and biodynamics can be informative. For example, selenium is accumulated to very high levels by bivalves but not by copepods in the same environment. The result is that in San Francisco Bay, striped bass, which eat copepods, are relatively unaffected by the metal, but sturgeon, which consume bivalves, are at risk, points out Luoma. The model “opens up a very different view of metal toxicity,” Luoma explains. “Because once you realize that species have different bioaccumulation of metals, you realize that some species are more vulnerable to metal levels. The next question is: What are these species? We are convinced that metal toxicity eliminates some species and others don’t see it as significant at all.” The work has another message, which applies to scientists and regulators. “The ‘B’ part of PBT [persistence, bioaccumulation, toxicity] varies so enormously among species,” says Rainbow, “but don’t despair, because with a few parameters, as in our model, we can begin to understand this!” —ALAN NEWMAN

courtesy of pham thi kim tr ang

ENVIRONMENTAL TECHNOLOGY Top paper: Helping developing countries detect arsenic “Bacterial Bioassay for Rapid and Accurate Analysis of Arsenic in Highly Variable Groundwater Samples” by Pham Thi Kim Trang, Hanoi University of Science (Vietnam); Michael Berg, Swiss Federal Institute of Aquatic Science and Technology (Eawag); Pham Hung Viet and Nguyen Van Mui, Hanoi University of Science (Vietnam); and Jan Roelof van der Meer, University of Lausanne (Switzerland), 2005, 39 (19), 7625–7630. Environmental chemist Michael Berg was immediately interested when he learned that Jan Roelof van der Meer, who was then a colleague at Eawag, had developed a bacterial bioassay that could analyze arsenic in water samples. Berg is working with environmental scientists in Vietnam, where he discovered that the groundwater and drinking water were heavily contaminated with arsenic. But the water-analysis laboratories in Vietnam, like those in Bangladesh, couldn’t afford sophisticated Western-style analyses to detect

Pham Thi Kim Trang and colleagues take water samples near Hanoi, Vietnam.

the toxic metal. Van der Meer’s assay seemed to be the answer. The method, which relies on genetically engineered E. coli bacteria that are bioluminescent in response to arsenite exposure, is cheap and simple to use. “It looked just like the ideal test to screen water samples in Vietnam for arsenic,” Berg recalls. However, Berg’s and van der Meer’s enthusiasm waned when they found that the reporter bacteria, april 1, 2006 / Environmental Science & Technology n 2089

whose performance had been validated with lab samples, could not correctly measure the arsenic in actual water samples from Vietnam. “Groundwater contaminated with arsenic is often anoxic, resulting in very high iron concentrations,” says van der Meer. “The arsenic sorbs to iron hydroxide precipitates and, as a result, is not bioavailable to the bacteria anymore.” The job of making the bioassay work fell to Pham Thi Kim Trang from the Hanoi University of Science (Vietnam), who came to Eawag to learn the new method. “I really wanted to bring this achievement from research to the real lives of people in my country,” says Trang. She succeeded in developing a pretreatment for the water samples that prevents iron from precipitating by acidifying the sample with nitric acid. A follow-up step that neutralizes the acid with pyrophosphate has the added advantage of simultaneously forming stable complexes with the dissolved iron. As a result, the problematic iron in Vietnamese water no longer impacts the bioavailability of arsenic to the reporter bacteria. Armed with her new method, Trang validated the protocol in Hanoi. She analyzed close to 200 groundwater samples of highly variable composition from across Vietnam, showing that the bioassay

produced better results than the chemical kits. To do that, Trang meticulously compared the results from the bioreporter bacteria with values determined by an established—and more laborious—approach that uses atomic adsorption spectroscopy. In October 2005, Berg, van der Meer, and Trang presented their successful method to local authorities and water laboratories from Vietnam, Bangladesh, and Nepal at a workshop in Hanoi funded by the Swiss Agency for Development and Cooperation. Despite the method’s usefulness, the researchers still face challenges to its acceptance. Vietnam has placed arsenic testing in a regulatory category that requires analysis of groundwater and drinking water only once per year; this makes it hard to promote the new approach for routine work in water-quality laboratories, says Trang. Her frustration is underscored by measurements of groundwater that she and Berg have made showing that arsenic levels in many samples exceed the national clean-water standard of 50 ppb. “More careful monitoring is needed in this country, but we cannot go ahead alone,” Trang says. The Hanoi University of Science is currently working on persuading the local authorities to acknowledge the arsenic problem in Vietnam and to assign regular arsenic screening to Trang’s laboratory. —ANKE SCHAEFER

Runner-up: A technology project with roots on two continents

top 2005 paper would not be possible without that advance. With the platinum safely sequestered inside the tube, all of its external surface is available to absorb photons to drive chemical reactions, the researchers explain.

“Preparation of a Novel TiO2-Based p–n Junction Nanotube Photocatalyst” byYongsheng Chen and John C. Crittenden, Arizona State University; and Stephen Hackney, Larry Sutter, and David W. Hand, Michigan Technological University, 2005, 39 (5), 1201–1208. In 1998, Yongsheng Chen took a big chance when he left his tenured position at Nankai University in his native China to follow his wife to the U.S. Chen left his country with 10 years, worth of experience investigating the behavior of TiO2. So he was delighted when he discovered that environmental engineers John C. Crittenden and David W. Hand at the Michigan Technological University (MTU) were also interested in the metal. Crittenden’s and Hand’s experience with titanium dates back to the early 1990s, when they coauthored research showing that adding platinum to colloidal particles of TiO2 produced a photocatalyst capable of partially oxidizing chemicals such as trichloroethylene (TCE) more efficiently than other available methods. “But at some point, if you add more platinum you start to coat the outside [of the particle] and the efficiency drops off because it interferes with the light absorption,” Crittenden explains. After Crittenden hired Chen to work in the MTU lab, the scientists began a period of very productive collaboration. For example, the MTU group was the first to find a way to get platinum to adhere only to the inside of TiO2 nanotubes. The 15-nm-wide p–n junction nanotube photocatalyst described in this 2090 n Environmental Science & Technology / april 1, 2006

Insights from research in the U.S. and China resulted in the creation of these semiconducting nanotubes.

“On the inside, you have a metal that would drain electrons away from the ‘holes’,” Crittenden explains. “You can create a situation where on the outside, you have oxidation reactions and on the inside you have reduction reactions,” he says. “Further, you get an electrical field that forms and helps improve efficiency.” Chen and Crittenden say that they are especially proud that they managed to create this device together with Hand in only a year with just $99,000 in funding.

In addition to detoxifying chemicals like TCE, the new catalyst has many other potential applications. They include creating sensors capable of detecting heavy metals as well as building a device capable of partially oxidizing light alkanes—such as methane— and aromatics with molecular oxygen. This is a key industrial process that is hard to control by using conventional approaches. Unfortunately, neither Crittenden, Chen, nor Hand has yet met with success in their attempts to encourage scientists in the chemical industry—or anywhere else—to investigate any of this technology’s practical applications.

By early 2004, Crittenden and Chen had moved to Arizona State University’s civil and environmental engineering department. There, the two are focusing on additional applications of the technology. They have shown that they can coat other materials onto the inside or outside of TiO2 nanotubes, Chen explains. This would allow them to create different kinds of semiconductors, such as transistors that control the flow of electrons across junctions, Crittenden says. They are also investigating how their catalyst could be used to produce hydrogen from biomass. —KELLYN S. BETTS

courtesy of Lester L aVe

ENVIRONMENTAL POLICY Top paper: Analyzing the idea no one talks about “Should We Transport Coal, Gas, or Electricity: Cost, Efficiency, and Environmental Implications” by Joule A. Bergerson and Lester B. Lave, Carnegie Mellon University, 2005, 39 (16), 5905–5910. Most chemical engineers, or graduate students, would find it difficult to collaborate on a research project with a world-renowned economist. However, Ph.D. candidate Joule A. Bergerson managed to find a common language with Carnegie Mellon University professor Lester B. Lave. Their efforts produced a hybrid life-cycle analysis (LCA) that examines the efficiency, economic cost, and environmental expense of transporting the U.S.’s abundant, low-sulfur coal from the vast surface mines in Wyoming to electric power plants as far away as Dallas, Texas. Several studies have already investigated the environmental impacts of electric power generation with coal, including one that examines the tradeoffs between transmitting electricity by overhead wires and transporting coal in trains. However, the latter study didn’t consider costs. Other research left out the expense associated with transmitting energy via power lines, the ES&T paper notes. In ES&T’s top policy paper of 2005, Bergerson and Lave take on the complex question of how best to exploit the coal reserves in Wyoming’s Powder River Basin (PRB), by comparing 4 alternatives that would each provide 6.5 billion kW•h of electricity to Dallas. They use a hybrid life-cycle analysis that combines the benefits associated with the Economic Input–Output LCA method with a more traditional approach developed by the U.S. EPA and the nonprofit Society of Environmental Toxicology and Chemistry. Lave—whose first LCA, in 1972, focused on an electric power plant—says he believes coal is a “terrible” fuel: “Almost everything about it is a problem.” In the U.S., more than 400 people die annually at train crossings as coal-laden cars speed through. When burned, coal produces pollutants such as particulate matter, SO2, and CO2. Nonetheless, he admits that because it is so cheap and now supplies at least 50%

Despite their different backgrounds, Lester Lave and Joule Bergerson proved to be a good team.

of U.S. power, coal will be a staple fuel for electricity for at least the next 20 years. Power demand is rising, “so we’re going to mine a lot of coal,” he says. Because coal reserves are located far from urban areas, shipping by train is the cheapest option, the authors say. But those costs depend on how far the coal travels and whether adequate rail lines even exist. Lave wondered: Could there be another, better way? His brainstorm was to convert the coal to synthetic natural gas at the mine mouth and ship it via pipeline to power plants. That approach would cost less and would certainly be more environmentally friendly. But PRB coal presents problems when gasified. “I didn’t have any idea of how to upgrade the gasified coal,” Lave admits. Bergerson’s knowledge of chemical engineering provided the missing element. “It was wonderful to have somebody here who could understand the reaction of the coal in the gasification process,” Lave says. “In this aspect, the science drove the LCA,” Bergerson adds. The pairing was also a dream come true for Bergerson, who, with an undergraduate degree in chemistry from the University of Western Toronto and a master’s in chemical engineering from the University of Toronto, had yearned to put her science to work on puzzles affecting public-policy decisions. “While I was working in the lab, I felt like I was holding myself back,” she recalls. That was one of the reasons she moved to Carnegie Mellon University’s engineering and public policy department, which specializes in teaching individuals “how to tackle april 1, 2006 / Environmental Science & Technology n 2091

policy problems that are dominated by technical details,” she says. “Lester and I worked really well together,” Bergerson adds. “Once you bring your head up from the calculations you are doing, you can put things into perspective.” Bergerson recently finished her joint Ph.D. in civil and environmental engineering as well as engineering and public policy, and she is now a postdoctoral

fellow at the University of Calgary (Canada). There, she is working on an LCA that examines unearthing the vast oil sands, or oil shale reserves, in northern Canada. These reserves are similar in quality to U.S. coal, Bergerson says, who predicts that each may last close to 450 years at the current extraction rate. “I’m excited about applying the framework that we developed for the coal research to the oil sands technology,” she adds. —CATHERINE M. COONEY

Runner-up: Calculating the environmental impacts of household consumption

out to create an approach for measuring sustainable consumption by looking at household consumption as a whole. Hertwich teaches courses on LCA at the Norwegian University of Science and Technology in Trondheim, but most of the work he does as a process engineer is based on input–output analysis (IOA), which is a tool of economics. In recent years, he notes, such research has been experiencing a renaissance as a result of the World Summit, and the trend has been to merge IOA with LCA into a sort of hybrid analysis. To calculate the impacts from consumption, “you clearly need a combination,” he says. “It would be impossible to use a processby-process LCA approach to assess all the activities we undertake as consumers, so you have to have a more aggregate assessment as well.” This is what IOA brings to the table: a way to look at the entire basket of goods that a household consumes. Information on consumption patterns typically comes from consumer expenditure surveys. To identify the most sustainable lifestyles, however, “we need to study households, and we need social scientists who can help with that,” because behavior plays an important role, Hertwich says. Some choices are clear, but others are more complex, and pro-environmental attitudes don’t necessarily correspond to more sustainable consumption. For example, take the car-free housing project that Hertwich and his colleagues studied in Vienna. Residents commit to not owning a car, and the money saved by not building garages is invested into common areas and more advanced energy management systems, such as solar energy. What they found is that such households have significantly lower CO2 emissions connected to energy use and ground transportation, as might be expected. However, the residents still have the same CO2 emissions connected to holiday travel, nutrition, and all of the other things that consumers do as folks living in other housing developments. These additional factors proved to be surprisingly important. Consequently, what Hertwich envisions is developing different types of projects where he tries to implement sustainable consumption on the basis of personal experiences and observations. He then uses LCA and IOA to evaluate them because “you don’t always get the results you think you will,” he says. He doesn’t pretend to have the ultimate answers but is hopeful that such research will at least show some of the trade-offs. —KRIS CHRISTEN

christian solli

“Life Cycle Approaches to Sustainable Consumption: A Critical Review” by Edgar G. Hertwich, Norwegian University of Science and Technology, 2005, 39 (13), 4673–4684. For Edgar G. Hertwich, the 2002 World Summit for Sustainable Development in Johannesburg was an inspiration. Participants called on world leaders to develop programs relying on life-cycle assessment (LCA) schemes to promote sustainable consumption and production patterns, and Hertwich responded with a new approach for measuring sustainable consumption. LCA has been used extensively to account for the resources consumed and emissions created during the manufacture, use, and disposal of individual products. However, during discussions with the “policy wonks” in Brussels who were struggling to implement the UN mandate, Hertwich discovered that they didn’t really know how to apply LCA in connection with sustainable consumption.

To buy or not to buy? Edgar Hertwich weighs the environmental pros and cons of his various food choices at a local grocery store in Norway.

“They were thinking mostly about using eco-labels that display life-cycle information,” Hertwich recalls, even though such labels haven’t proved very helpful for consumers. “If you tell [people] that there are so many kilograms of acidification potential associated with a certain product, nobody can really make much sense out of that sort of information,” he explains. So, with some EU funding, Hertwich set 2092 n Environmental Science & Technology / april 1, 2006