Thursday, August 27, 2009

H20 Woes: Measuring the Damage of our 'Water Footprint' - SPIEGEL ONLINE - News - International

http://www.spiegel.de/international/world/0,1518,644867,00.html

By Samiha Shafy

A Dutch hydro engineer has come up with a "water footprint." At a conference in Sweden, he and other participants discussed water waste, supermarkets filled with fruits and vegetables produced in some of the world's most arid regions and ways we can stop wasting our most precious resource.

Arjen Hoekstra didn't really stand out in the crowd of 2,000 scientists, activists, politicians and representatives of industry roaming the halls of the Stockholm trade fair. Far more attention-getting figures than the 42-year-old Dutch hydro engineer attended World Water Week in Sweden last week. Asian delegates wore glowing saris. And Indian businessman Bindeshwar Pathak drew flocks of media everywhere he went at the event after being named the recipient of this year's Stockholm Water Prize for inventing a toilet for slum dwellers.

But Hoekstra preferred to keep a low profile at the annual global conference, which focuses on water-related issues. He had nothing to prove. Still despite his apparent efforts to keep a low-profile, Hoekstra's creation served as a magnet for debate here. Hoekstra came up with the idea of the "water footprint."

10,000 Liters of Water for a Pair of Jeans

His equation is actually just a couple of numbers used to describe the amount of water that is used -- or polluted -- during the manufacture of various products. Anyone can calculate their water footprint by looking at the amount of water they use directly and then by looking at the amount of "virtual water" they use -- that is, how much water is used in the production of any goods they consume. The global average for an individual's water footprint is 1,243 cubic meters of water per year. In the US, this goes up to 2,483 cubic meters per year; in Germany it's 1,545 and in China, 702.

Hoekstra's water footprint formula has already made headlines around the world with its estimates of the amount of water that is used or abused in the simple products that are a part of our everyday lives:

  • 140 liters of water for one cup of coffee!

  • 2,400 liters for a hamburger!

  • 10,000 liters for one pair of jeans!

In the dicussions and workshops in Stockholm, participants debated what sort of action should be taken as a result of the water footprint figures. The WWF environmental group first recognized the validity of the water footprint, and further conservation and environmental protection groups as well as the United Nations and the World Bank soon followed suit. Finally, even multinational companies like Nestle, Unilever and Pepsi got on board.

Virtual Water Heading In The Wrong Direction

And they all seem to agree that Hoekstra's numbers could be potentially explosive -- mainly because they make it clear how thoughtlessly water, the most precious of resources, is handled in so many areas. "Because of the international trade in water-intensive products, there are floods of virtual water flowing around the world," Hoekstra said. "And many of them are flowing in the wrong direction, going from water-poor regions to the water-rich."

Mostly these flows involve food, biofuels and cotton. Between 70 and 80 percent of all the water consumption in the world is used for agricultural purposes. The European Union, for example, contributes indirectly to the drying out of the ever-shrinking Aral Sea in Kazakhstan and Uzbekistan through its cotton imports from the region. And when the Germans buy ham from Spain or oranges from Israel, they are also contributing to water scarcity in those areas. In fact, Germany, a country that has plenty of water, is one of the biggest importers of virtual water in the world.

Today, around 1.4 billion people live in areas where water is scarce. Climate change, population growth and the flows of virtual water only serve to exascerbate the problem. "By 2050, we will be confronted with the paradoxical situation of having to feed another 2.5 billion people, but with significantly less water," said Colin Chartres, director general of the International Water Management Institute, an internationally funded, non-profit organization looking into ways to improve land and water management.

'In Dry Areas There Should Be No More Agriculture'

Against that backdrop, delegates in Stockholm argued about how realistic Hoekstra's more radical ideas are. "In dry areas there should be no more agriculture," the Dutchman has suggested. His idea involves using the trade in virtual water to rebalance the earth's water budget. Instead of watering desert fields, Egypt would be better off importing beans or millet from Ethiopia, for example. And Australia, where the Outback is one of the world's most arid regions, should also cease to export virtual water in the form of meat, fruit and wine production.

The same arguments could be applied to all of Earth's dry zones -- from the Middle East to northern China and northwestern India to Southern California. Hoekstra says all of these regions could mitigate their water paucity by letting their fields dry up and importing more virtual water. "These water-poor regions need to come up with a new vision for the future," Hoekstra argued. "Just as the oil producing countries, where oil is starting to run out, have had to do."

But what would make any country abandon agriculture, altogether or partially? British environmental researcher Tony Allan, 72, first coined the phrase "virtual water" in the 1990s and he agrees with Hoekstra. "Singapore is an interesting example," he said. "They don't have water sources or agriculture. Ninety percent of their water needs are covered by the import of virtual water. The rest comes from recycling and desalination."

Rich Countries Buying Up Land To Insure Water Supplies

Of course, Allan knows that Singaporean model isn't necessarily appropriate for the rest of the world. Even he admitted that no country would voluntarily give up its agricultural practices in the foreseeable future. "But it is no longer taboo to talk about these things," he noted.

During the Stockholm workshops, experts quickly agreed that new pricing structures could steer the water trade in the right directions. Today, water prices are often distorted through government subsidies to farmers -- mainly because if the subsidies were not there, then agriculture and animal husbandry would very quickly become prohibitively expensive in those dry regions and no longer worthwhile.

Meanwhile, countries like China and Saudia Arabia are buying up large, fertile pieces of land in places like Africa, Asia and Latin America. By buying land instead of food, they are ensuring access to water in the future. The land-grabbing countries aren't alone, either -- they're competing directly with food production giants like Nestle and Coca-Cola, which have been buying up rights to water reservoirs around the world for years.

Many companies are welcoming the increasing debate about water footprints in Stockholm. It's a great opportunity for them to do something to improve their image. Indeed, several large corporations sent whole delegations to Stockholm. At the workshops, the delegates continually repeated the same message: Their employers are trying their very best to leave a smaller water footprint.


 

Thursday, August 6, 2009

Popular Insect Repellent Deet Is Neurotoxic

http://www.sciencedaily.com/releases/2009/08/090804193230.htm

ScienceDaily (Aug. 6, 2009) — The active ingredient in many insect repellents, deet, has been found to be toxic to the central nervous system. Researchers say that more investigations are urgently needed to confirm or dismiss any potential neurotoxicity to humans, especially when deet-based repellents are used in combination with other neurotoxic insecticides.

Vincent Corbel from the Institut de Recherche pour le Développement in Montpellier, and Bruno Lapied from the University of Angers, France, led a team of researchers who investigated the mode of action and toxicity of deet (N,N-Diethyl-3-methylbenzamide). Corbel said, "We've found that deet is not simply a behavior-modifying chemical but also inhibits the activity of a key central nervous system enzyme, acetycholinesterase, in both insects and mammals".

Discovered in 1953, deet is still the most common ingredient in insect repellent preparations. It is effective against a broad spectrum of medically important pests, including mosquitoes. Despite its widespread use, controversies remain concerning both the identification of its target sites at the molecular level and its mechanism of action in insects. In a series of experiments, Corbel and his colleagues found that deet inhibits the acetylcholinesterase enzyme – the same mode of action used by organophosphate and carbamate insecticides.

These insecticides are often used in combination with deet, and the researchers also found that deet interacts with carbamate insecticides to increase their toxicity. Corbel concludes, "These findings question the safety of deet, particularly in combination with other chemicals, and they highlight the importance of a multidisciplinary approach to the development of safer insect repellents for use in public health".


Journal reference:

  1. Vincent Corbel, Maria Stankiewicz, Cedric Pennetier, Didier Fournier, Jure Stojan, Emmanuelle Girard, Mitko Dimitrov, Jordi Molgo, Jean Marc Hougard and Bruno Lapied. Evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet. BMC Biology, (in press) [link]
Adapted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.