Australian government scientists have proposed a novel water trading system to allocate and manage water for irrigation. Water users would be able to trade water shares and allocations via electronic transfers with licensed brokers and clear trading rules. But they could only use their water allocation under certain conditions that would protect other water users and the environment. Australia already has water trading and allocation systems but these contain serious flaws, according to Mike Young and Jim McColl of CSIRO, the government research organization that recently released a report discussing the idea. “Current systems were not designed for water management in an environment where periodic drought is the norm, water resources are scarce, and climatic conditions change.”
The state government of South Australia is seriously considering the proposal for the River Murray system (see map), which reaches into Queensland, New South Wales, Victoria, and South Australia, says Young. “There are currently more than 26 allocation systems in the basin, and there is an official proposal to reduce allocations by 10%, which will mean a need for massive adjustment. The pain will be a lot less if water is tradable across the entire system.”
The system has three components: an entitlement, an allocation, and a use license. The entitlement is the long-term interest, or share, in the water resource. It defines the degree of access that a farmer can expect over time. The CSIRO team recommends that the government should manage these entitlements in a system like the share registry systems for trading company shares. An allocation is the quantity of water that a farmer may use or trade during a specified period. The team recommends that allocations should be managed like bank accounts with debits, credits, and balances. Trades and extractions from the pool for irrigation, for example, would be debited from these accounts, with users writing water checks or trading over the Internet. The team recommends clear trading rules including exchange rates with separate registers for entitlements and accounts for allocations.
The final component is a use license, or the right to apply water to land. This is how regulators would manage impacts on the environment, neighbors, and downstream water users. The license would specify conditions such as pumping limits and drainage disposal requirements. Young claims that the novelty of
News Briefs Hybrids could get 60 mpg The U.S. automotive fleet could average 60 miles per gallon (mpg) by 2020 if automakers use the best hybrid gas–electric technologies, according to a report from the Union of Concerned Scientists (UCS), a nonprofit research group. Welldesigned hybrids that combine electric drive motors with the best conventional technology for combustion engines will cost about $4000 more than a conventional car or truck, the report says. But if the hybrids don’t use the best available conventional technology for combustion engines, they will not even do as well as the best available conventional technology, which could increase the average to 40 mpg without hybrid technology. A New Road: The Technology and Potential of Hybrid Vehicles is available at www.ucsusa.org.
Moving closer to a sustainable economy Recent advances in renewable energy, combatting infectious diseases, and decreasing poverty suggest that some parts of the world are moving toward a more sustainable economy, but efforts still need to be scaled up to the global level, according to the Worldwatch Institute’s annual report. The report highlights recent success stories. For example, solar and wind power are both growing at more than 25% per year; several countries have adopted car-free days and car-sharing programs; and organic farming is the fastest expanding sector of the world agricultural economy. The report emphasizes increasing interest in sustainable economic growth among diverse sectors of society, including religious organizations. State of the World 2003 can be purchased at www.worldwatch.org/bookstore.
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Australians consider novel water trading scheme
Environmental▼News this approach is separating the three components, and allowing different organizations to manage each piece on different scales. A basinwide agency could issue shares involving many states. A State Department of Water Resources or a water supply company could manage allocations, and an environmental protection authority could manage licenses. The approach could operate across the whole country, with trading between regions if they were linked hydraulically, for example, between the Murray River system and the Snowy River. An important advantage of the system is that the managing organizations could control trade and extractions as climatic, economic, and technical circumstances vary, says Young.
The most unusual aspect of the proposal is the license, which could help protect the environment, says Jim Boyd of Resources for the Future, a think tank in Washington, D.C. Water trading involving entitlements and allocations does occur in the United States in California, Colorado, Nevada, and Arizona, where water can be scarce. However, he says, water transfers can have significant environmental consequences, affecting wildlife, salinity of aquifers, and dilution of pollutants. If the license safeguards against these environmental concerns, then Boyd believes that a market-based approach has many benefits. “The price will effectively signal the resource’s scarcity, so higher prices should result in reduced use and more conservation.”
However, environmentalists are cautious. Tim Fisher of the Australian Conservation Foundation points out that on the Murray Basin, for example, increasing trade in water from upstream to downstream locations will further disrupt natural flow patterns already altered by dams. However, he does acknowledge that trading would bring some environmental benefits, such as taking water away from areas with high water tables and big salinity problems to areas where it could be used more efficiently. Copies of the report Robust Separation: A Search for a Generic Framework To Simplify Registration and Trading of Interests in Natural Resources can be downloaded from www.clw.csiro.au/ research/agriculture/economic/ publications.html. —MARIA BURKE
New concerns about arsenosugars in seaweed and shellfish senosugar metabolism. “That means that the accumulation of arsenic in sheep that we see may also appear in humans,” says Feldmann. JÖRG FELDMANN, UNIVERSITY OF ABERDEEN
Naturally occurring arsenosugars in seaweed and some shellfish may be more toxic than previously thought, according to new research conducted on sheep living on an island north of Scotland whose major food source is seaweed. The findings, which are reported in this issue of ES&T (pp 845–851), show that sheep metabolize arsenosugars very rapidly into pentavalent dimethylarsinic acid, (CH3)2AsO(OH) or DMA(V), which is considered a potential co-carcinogen. Although the implications for human consumption of seaweed and shellfish containing arsenosugars are still unclear, studies have shown that humans also metabolize arsenosugars to DMA(V). “We observed no toxic effects in the sheep,” says lead author Jörg Feldmann of the University of Aberdeen in the United Kingdom. “However, they are slaughtered when they are young, on average when they are four years old. So you can’t actually say whether they will get cancer when they are older.” What is surprising is that the sheep model is very similar to human metabolism in terms of ar-
Sheep that live on one island north of Scotland consume large amounts of seaweed that contains high levels of naturally occurring arsenosugars. New research suggests that these arsenosugars may not be as safe as previously thought.
There have been only limited studies on human exposure to arsenosugars, despite their prevalence in seaweed and edible bivalves, such as clams, oysters, and mussels. In one short-term study conducted by co-author Kevin Francesconi and colleagues at KarlFranzens-Universität Graz in Austria, a pure arsenosugar com-
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pound was chemically synthesized and ingested by a human. In that study, the quantity ingested by this one person was comparable to what a Japanese person eats in one day, says Francesconi. “The main metabolite was DMA(V), but there were several others that we identified and some we could not identify. The metabolites were excreted rapidly. After four days we had accounted for about 80% of what was ingested,” he says. Although, in one sense, no one has looked at the long-term effects of eating arsenosugars, in another sense, they have, “because the Japanese eat vast quantities of these edible algae and have been doing so for many years,” adds Francesconi. “There is no evidence to suggest that their incidence of certain cancers is higher than nonalgal eating groups,” he says. Still, there is only one animal study in the literature showing that there is not very high toxicity of arsenosugars to rodents, says X. Chris Le, a professor in the environmental health sciences program at the University of Alberta–Edmonton in Canada. “That doesn’t mean there are no health effects from arsenosugars in seaweed,” he says. DMA(V) is about 100 times less acutely toxic than inorganic ar-
