of damage (77%) from cotton production, whereas Brazil experiences the lowest level of damage (0%), followed by the U.S. (4%). address ecosystem impacts and Despite water’s significance, modThe model’s focus on the reknown as PDF (potentially disapeling how freshwater consumpsulting damage to ecosystems and peared fraction of species) to extion for drinking, industrial human health is somewhat conpress how water impacts species. manufacturing, and agriculture troversial among LCA practitionLCAs routinely rely on aggrehas affected ecosystems, human ers in general, some modelers gated data to represent large arhealth, and the depletion of nontold ES&T. Many U.S. researchers eas. But the ecological impacts of renewable freshwater resources tend to stick to LCAs that create water use depend on regional fachas been overlooked. In a new resource-use inventories ES&T study (DOI 10.1021/ but that don’t measure es802423e), researchers ecological or humantake the traditional lifehealth impacts, notes cycle assessment (LCA) Christopher Weber of Carapproach one huge step negie Mellon University. beyond current practices Referring to the new ES&T with a model that incorpostudy, Weber says: “There rates water consumption. is a great deal of uncerLCA models were cretainty in their inventory, ated to address problems The damages to ecological systems from overconsumption and there is still disagreein industrialized nations, of water are illustrated in this world map (yellow represents ment over many of the and most of these coundefinitions they use.” tries don’t experience hu- low impacts, navy high impacts). Modelers in the U.S. also man-health risks due to tors, such as freshwater availabilshy away from incorporating wawater scarcity, the authors note. ity, water infrastructure, rainfall, ter into LCAs because there is a Recently, researchers have started and consumption patterns at a shortage of water data in this to use LCA models to manage dispecific location. The team used a country, explains Chris Hendrickminishing resources in developing geographic information system to son, also of Carnegie Mellon. countries. To incorporate water gather regional data and divided More data are available for the consumption into the LCA prolarge rivers, such as the Nile and EU, and for areas with water scarcess, Stephan Pfister, Annette the Mississippi, into subcatchcity, such as in Israel. Koehler, and Stefanie Hellweg at ments. “The watershed level is Nonetheless, the study demonthe Swiss Federal Institute of more appropriate for the assessstrates a huge range of work, WeTechnology Zurich’s (ETH Zument, because hydrological prober says. “I absolutely think that rich’s) Institute of Environmental cesses are connected within [the] method they are using is a Engineering started from scratch: watersheds,” Pfister says. good one,” he says. “It’s good to they created units of measure for take the next step and to turn waIn the paper, Pfister and colwater consumption that are comter use into something that can leagues demonstrate their model patible with the many values for be used to compare it to somewith a case study of a process energy and resource use that apthing else, such as toxic releases that is water-intensive worldwide: pear in an internationally recogor CO2.” cotton production. They began nized LCA method. “For water with data from the “virtual water” use, this hadn’t been done, ever,” Determining water use “has redatabase developed by researchsays Hellweg, who is a professor ally become popular in the last ers in The Netherlands. A relaof ecological systems design at year,” Hellweg says. “But compatively new idea, virtual water ETH Zurich. nies are not really looking at what describes the amount of water For example, the team interhappens afterwards, and they are that evaporates during agriculpreted a well-known value estaball looking at water use in an agtural use. Specifically, the datalished by the World Health grandized area,” she adds. “I rebase is an inventory of the water Organization in LCA models and ally hope that businesses take this consumed for agricultural use for applied it to water use. The disone more step and incorporate many crops in most countries. ability-adjusted life year is a value the differences of water use in The team found that the imthat expresses the number of Egypt compared with water use in pacts from water consumption in years a person’s life will be shorta wet country such as Switzerthe cotton industry vary accordened as a result of disease or preland,” Hellweg says. ing to country: Egypt’s water supmature death. The team also —CATHERINE COONEY ply experiences the highest level adapted an indicator applied to FIGURE 2, PFISTER ET AL.
LCA finally takes water into account
3986 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / June 1, 2009
10.1021/es901078v
2009 American Chemical Society
Published on Web 04/22/2009
