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Straight ahead on "Our World" ... Controversial new air pollution rules ... The quest for safe drinking water as nations mark World Water Day ... and a warning about obesity...
ALLISON:  "It is increasing in China. It is increasing in Africa. It is increasing in the East. It is increasing in the West. It is increasing in almost every segment of the world."

Those stories, women and their X chromosome, and more.  I'm Art Chimes.  Welcome to VOA's science and technology magazine, "Our World."


The Bush administration this week announced new rules to limit mercury emissions from the nation's coal-burning power plants.

Mercury is a highly toxic heavy metal. Smokestack emissions can end up in rivers and oceans and are absorbed by fish. Certain kinds of fish can have dangerous concentrations of mercury. The administration says the new rules will cut emissions by half within 15 years. In announcing new rules on mercury emissions, senior Environmental Protection Agency - EPA - official Jeff Holmstead told reporters that the administration's market-oriented approach to pollution control will accelerate the reductions.

HOLMSTEAD:  "The rule creates a very strong incentive for early reductions, so our analysis shows that even though the cap level is set at 38 tons in 2010, we project that actual emissions will be about 31 tons.

Under a so-called "cap-and-trade" system, the government sets a maximum limit for mercury emissions, but lets companies buy and sell pollution credits. In other words, a company can reduce its emissions by more than the required amount, then sell credits to another company, which may find it cheaper to pay for the credits than to reduce its emissions.

The cap-and-trade system has been used for other pollution control programs, but many environmentalists criticize the system as providing a "license to pollute" for those who can pay. But the EPA's Jeff Holmstead says cap-and-trade is the most cost-effective way of reducing emissions.

HOLMSTEAD:  "Importantly, it also creates an incentive for the continued development and testing of very promising mercury-specific control technologies that are efficient and effective and can be transported and exported to other parts of the world."

One environmental group, the Natural Resources Defense Council, called the new rule "irresponsible" and a threat to children. Jon Devine, with the group's Washington office, says the administration's estimates of reductions are flawed.

DEVINE:  "Let's be clear. This cap-and-trade scheme, because power plants can buy pollution credits rather than clean up, will not reduce mercury pollution by 70-percent in 2018 as is often reported."

And Mr. Devine, who is a lawyer, says the EPA mercury rule violates a federal law called the Clean Air Act.

DEVINE:  "The current law requires sources of hazardous pollutants, like mercury, to install the maximum achievable controls and to do so within a very short timeframe -- three years. What EPA's rule does is to give power plants an extended timeframe to do much less than what is maximally achievable."

The EPA concedes that mercury emissions will continue to find their way into the food supply, and agency official Jeff Holmstead stressed that consumers should be aware of what they eat.

HOLMSTEAD:  "It will be for many years important for women of childbearing age to pay attention to the guidelines so that they can limit their consumption of certain types of fish that we know have the highest mercury concentrations."

Children and nursing mothers are also advised to limit consumption of certain fish, such as shark, swordfish and some kinds of canned tuna.

Coal-burning power plants release about one-third of U.S. mercury emissions. The United States contributes an estimated three percent of the world's annual mercury pollution.

This Tuesday is World Water Day, and the beginning of a U.N.-mandated decade of action called "Water for Life." 

The first water decade, which ended 15 years ago, brought clean water to more than one billion people and sanitation to almost 770 million.  This new water decade aims to improve health by further extending clean water and sanitation. But as VOA's David McAlary reports, the goal of safe water remains elusive as world population grows.

McALARY:  Earth may be unique in the universe for its abundance of water.  But the image recalls the old sailor's lament, "Water, water everywhere, but not a drop to drink."

PETERSON: "It is really remarkable that on the blue planet, on a planet as abundant with water as the one on which we find ourselves, only three percent of the water resources on the planet are fresh water."

McALARY:  Erik Peterson of the Center for Strategic and International Studies in Washington points out that as small an amount as three-percent is, only a tiny fraction of that percentage is available to us for daily use.  Most of the world's fresh water is either frozen, locked underground or in swamps, leaving less than a drop in every liter for our needs.  Half of that is already in use for agriculture, industry, and cities and towns.

But about one-sixth of humanity, one-billion people, do not have safe water and two-and-one-half billion are without sanitation.  U.N. statistics show that nearly half of all people in the developing world suffer diseases like cholera and diarrhea as a direct result.  As population grows, Mr. Peterson says more will be exposed.

PETERSON:  "By current estimates from the United Nations, we believe that by the year 2025, some three-billion people across the world could face water shortages, in some cases life threatening water shortages."

McALARY:  Despite the minuscule amount of available fresh water, experts say there is enough to meet human needs.  The real problem is that the infrastructure to deliver it, such as sewage treatment plants and pipes, is lacking in many countries.

The outcome is that much labor that could otherwise be economically productive in poor countries is spent   water long distances on foot from rivers and lakes.

In 2000, U.N. members set a goal of reducing the percentage of people lacking clean water and sanitation by half as one of several so-called Millennium Development Goals to be met by 2015. 

But the Center for Strategic and International Studies says the effort is underfunded and will require an extra $15-30 billion in addition to the $30 billion already invested each year in development.

Experts say demand for water must be reduced as population increases.  

For Massachusetts of Institute of Technology engineer Susan Murcott, part of the answer is new technologies to increase water efficiency.  She favors simple, inexpensive ones for poor countries. Ms. Murcott has developed a filter of brick chips, rusty nails, sand, and gravel in a tub to eliminate arsenic and other contaminants from water.

MURCOTT:  "There may be a movement maybe not away from centralized drinking water and wastewater treatment plants, but certainly an additional component of decentralized solutions that we are going to be seeing because water supply for so many people around the world is coming to people from decentralized sources."

McALARY:  To this end, the World Health Organization is collaborating with more than 200 governmental and non-governmental organizations, corporations, and universities in an international network to promote research into safe, affordable household water treatment, and ways to make it available to every person who needs it.   (SIGNED)

From mathematics to science fiction, the letter X is often used to represent the unknown. Well, one particular X is a little less unknown this week. The X chromosome, that is. This week, international researchers have reported the first complete analysis of the X-chromosome, which is linked to more than 300 diseases.  VOA's Jessica Berman reports.

BERMAN:  The findings in two studies published this week in the British journal "Nature" might explain how the X-chromosome determines the differences between men and women.

Chromosomes are microscopic coils of genetic information located in each cell of every living thing. 

Humans have 22 pairs of chromosomes plus the gender chromosomes, X and Y - each inherited from one of their parents.  Women have two X-chromosomes, while men have an X and a Y.

The researchers say it appears that women's genes appear to work harder than men's to influence the fate of both genders.

They found evidence that 75-percent of the time, before it's born the healthy female body switches off one copy of its X-chromosome that might cause disease. 

Researcher Laura Carrel of Penn State College of Medicine in Hershey, Pennsylvania, says usually, there is no problem in women whose bad genes do not switch off.

CARREL: "For others, though, it brings up a new intriguing possibility that these are contributing to particular disorders, potentially in how they are manifested, potentially in how they progress, how they respond to particular treatments.  And so this would give us kind of new avenues to look at in looking at diseases that seem to affect males differently than females or that tend to have different variability in females."

BERMAN:  In men there is nothing to switch off.  So an abnormal copy of an X-protein might explain why certain X-linked diseases, such as hemophilia and Duchenne's muscular dystrophy, are only seen in men.

Researchers also mapped the locations of genes on the X- and Y-chromosomes.  The study of the human genetic material is expected to help understand the causes and aid diagnosis and treatment of inherited ailments, including mental retardation, testicular cancer, and immune system disorders. (SIGNED)

MUSIC - "Kind Hearted Woman Blues" (Eric Clapton)

You're listening to VOA's science and technology magazine, ?Our World.? I'm Art Chimes in Washington

Government statistics indicate that growing numbers of Americans are seriously overweight, and new research published this week suggests that what some have called an "epidemic" of obesity could reverse a decades-long trend of improved life expectancy.

The problem, says researcher David Allison, is that the extra weight that obese people carry has medical consequences.

ALLISON:  "The more obese you get, the more risk you have for earlier mortality, for heart disease, for gall bladder disease, for certain forms of cancer, for diabetes, for high cholesterol, for atherosclerosis, and so on and so on."

In a study in the New England Journal of Medicine, researchers calculated that obesity currently reduces life expectancy by three to nine months for Americans as a whole. That may not sound like a lot, but it's comparable to the reduced life expectancy from accidents, suicide and homicide combined.

Later this century, the effects of obesity could actually reduce life expectance, which has been steadily increasing for decades. Co-author Doug Passaro of the University of Illinois at Chicago says it's because today's young people are considerably fatter than their parents.

PASSARO:  "Our real concern is if you look at adolescents and young adults now. Their rates of obesity are so high that we could easily lose five to ten years of life expectancy if their rates of obesity are unchecked by the time they reach older adulthood."

The authors of this study are projecting current trends, and Dr. Passaro told me that the grim forecast is as much warning as prediction, and he hopes they are wrong.

PASSARO:  "What we are hoping is that this is a call to action [which] will make people realize that we can't treat overweight persons in a vacuum, but we need to think about population strategies, that is community strategies and societal strategies."

Another co-author on the study, David Ludwig of Boston's Children's Hospital, said that unless obesity is reduced, it's possible that heart attacks may become common among young adults.

Although this study was done in the United States, obesity expert David Allison at the University of Alabama?Birmingham says it's a global problem.

ALLISON:  "Obesity's increasing in almost every segment of the world's population. It is increasing in China. It is increasing in Africa. It is increasing in the East. It is increasing in the West. It is increasing in Europe. It is increasing in Latin America. It is increasing in almost every segment of the world."

The causes of obesity are varied, and controversial. Increasing prosperity brings with it more food and, often, a more sedentary lifestyle. But many social critics blame so-called lifestyle causes, such as increased consumption of fast food and heavy advertising by companies selling convenient but less-healthy processed foods.

We've been talking about obesity, but who is obese? The generally-accepted definition is a person with a body mass index, or BMI, of 30 or higher. To calculate your BMI, take your height in meters and square it - in other words, multiply it by itself. Then divide that into your weight in kilos to get your BMI. A BMI under 25 is considered normal, 25 to 30 is overweight, and higher than 30 is considered obese. If you don't want to do that much math, we have a link on our website that will do it for you at

You know, in many ways the health of a society can be measured by the health of its people. Infant mortality, for example, is commonly used to grade a country's economic and social development. Tracking health statistics in the United States is the job of a government agency with a straightforward name, the National Center for Health Statistics, or NCHS. And we've chosen their online home at - - as our Website of the Week.

RAMIREZ:  "NCHS is Congressionally mandated to collect statistics in a number of areas of health. And our big goal - the mission here - is to really monitor the nation's health."

Sharon Ramirez is a spokesperson for the Center for Health Statistics, which gathers an astonishing variety of health-related information, all in one place. Perhaps its most comprehensive document is an annual summary called "Health, United States," and the website includes 30 years of back issues. But this website is also great for up-to-the-minute information.

RAMIREZ:  ""All of our publications that are produced are available on our Internet site. They're actually available even before the printed copy comes back. As soon as we get something ready to go to print, the publication goes up on the Internet."

Topics range from alcohol use to health spending to kidney disease to causes of death. The data is available in a variety of formats, including downloadable spreadsheets and PowerPoint presentations.

Visitors to the website can also subscribe to mailing lists called listservs on a variety of topics, including women's and minority health, and injury statistics.

RAMIREZ:  "It's a quick way for people to find out when new data's released, to ask questions of the program. Or also, they may pose a question to the listserve and then other people may answer that question."

Some of the data on the site is available in Spanish, and Ms. Ramirez says they'll try to answer questions in your language - whatever it is - if you send it in using the "contact us" feature.  For a wealth of information about the state of health in the United States, surf on over to the National Center for Health Statistics at, or get the link from our site,

Visitors to the U.S. Botanic Garden here in Washington are getting a rare chance to look at ancient plant history.  Inside a Plexiglas case is a small tree whose family roots date back to the age of the dinosaurs. The recently-discovered tree is closely related to trees that flourished some 200 million years ago.  VOA's Rosanne Skirble has our story...

SKIRBLE:  The U.S. Botanic Garden is giving the 3-year old specimen - about half a meter high - a protected start in life.

FLANAGAN:  "This exhibit is really all about the excitement about finding something brand new. And suddenly we have a living fossil of which the last known living populations were 90 million years ago."

SKIRBLE:  Christine Flanagan is a spokeswoman for the U.S. Botanic Garden, which is cultivating the Wollemi Pine under a trial program with the Royal Botanic Garden and Domain Trust, an Australian environmental group.

FLANAGAN:  "This tree provides us a window on all of the evolution of an entire plant family that we don't know that much about, and in its genes is the story of how it survived from the Jurassic until today."

SKIRBLE:  The Wollemi Pine was discovered ten years ago by a park ranger and avid bushwalker in a remote wilderness area near Sydney.  John Benson  - senior ecologist at the Royal Botanic Garden in Sydney - monitors the hidden grove of about 100 Wollemi. He says the conifer-like pine is a new genus in the 200 million year old Araucariaceae family.

BENSON:  "It grows up to about 40 meters high and up to about a meter in diameter.  It has got a very unusual bubbly chocolate colored bark that I have never seen on another tree species anywhere.  At the juvenile stage, the leaves look a little bit ferny.  As the tree grows the leaves change and become too hardened, more spiky looking leaflets." 

SKIRBLE:  The location among steep canyons in Wollemi National Park remains a secret.  The park wants to keep curious hikers - who might trample the trees or bring in disease on their boots - away.  

John Benson says the Royal Botanic Garden and Domain Trust Sydney are behind an effort to conserve it through propagation.  They are working with test gardens in Australia and elsewhere around the globe. 

BENSON:  "And, they have found out things like they can withstand temperatures from minus 5 [degrees Celsius] to plus 45.  It can withstand a little bit of frost.  It certainly would be a suitable potted plant for the northern part of America and Europe and Japan, and it would grow in gardens in the mid-latitudes fairly easily.  And, they have found that it grows in a wide variety of soils as well."

SKIRBLE:  "What is like to be near a tree that has this kind of history?"

BENSON:  "I feel that I am basically back in the dinosaur period. It is a relic that has hung on there.  It didn't want to go extinct.  It somehow survived ice ages and drought and fire.  And just going back and looking at what things must have been like 50 million years ago!"

SKIRBLE:  On the other side of the world visitors to the U.S. Botanic Garden in Washington are getting some sense of that history as they stare at the Wollemi in the Plexiglass case.

MAN:  "I think that it is very cool that it is that ancient of a tree, the fact that it has been around that long!"

WOMAN:  "I was just thinking how many species are going extinct without us even knowing that they existed.  And, this is obviously one that I did not know existed."

SKIRBLE:  The Royal Botanic Garden and Domain Trust Sydney are expected to release the propagated plants for sale in October.  I'm Rosanne Skirble.

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Our World is edited by Rob Sivak. Our technical director is Eva Nenicka. And this is Art Chimes, inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and Our World.