Geologists Tracing Path Of Life-Threatening Arsenic
BY ALEXANDRA WITZE
The Dallas Morning News
February 24, 2003
Linda Smith works in a country terrorized by Maoist guerrillas. Traveling alone, she carries only a slingshot - but that's for protection against aggressive monkeys.
Her real enemy, though, is poison.
Arsenic is leaching from the mountains of Nepal. Slowly, inexorably, the poison seeps downstream and enters the groundwater of India and Bangladesh.
Millions of people are drinking from wells naturally laced with arsenic. Millions are suffering from what the World Health Organization calls the worst mass poisoning in history.
Smith, a geologist, hunts the source of that poison. From her homes in Dallas and Colorado, she coordinates a small group of scientists who think they can learn why so many people are getting sick.
It is the first international effort to find the arsenic-laden rocks of Nepal. By tracing the arsenic upstream, these researchers hope to discover which rocks release the deadly poison. That information could help Southeast Asians determine why some water sources are safe and others are not.
But Smith would never have started the project if it had not been for Sept. 11, 2001.
A lifetime spent working in oil and gas prepared Linda Smith for Nepal. Over the years, she has traveled on academic and industry assignments through much of Asia, including studies in Azerbaijan and Turkmenistan and a stint with the Indonesian Research Council. She is an expert in sequence stratigraphy, the details of how oil and gas deposits are layered in the earth and where they are most likely to be found.
Smith worked for several years for Mobil in Dallas, creating computer models that helped point the way to energy resources. In 1997 she moved to Boulder, Colo., to do similar studies for the U.S. Geological Survey. By the fall of 2001, the Fulbright scholar-exchange program had awarded her a fellowship to teach sequence stratigraphy at the University of Peshawar in Pakistan.
Then came Sept. 11.
Barred in the aftermath from working in Pakistan, Smith rattled around her USGS office in frustration. Then she arranged a teaching position at Tribhuvan University, Nepal's national university, through Fulbright.
"Nepal is probably one of the most exciting places you can do work in," she says. "Everywhere you go, there's geology."
Two months later - she still remembers the date, Nov. 12 - a colleague told her that arsenic had just been discovered in the river waters of Nepal.
The poison, she learned, was coming from the majestic Himalaya Mountains that line Nepal's northern border. Somewhere, hidden deep within the mountains, is a layer of rock that carries arsenic. Like the rest of the sediments, it had been laid down when the area rested at the bottom of an ocean. Over the course of millions of years, geologic forces smashed India and Asia together, raising the Himalayas to their mighty height and exposing the arsenic-rich rock.
Each year, the powerful Asian monsoons drench the mountains and send masses of water flooding downstream. Carried along with it is the dissolved arsenic.
No one had recognized just how far the arsenic traveled until the mid-1990s, when UNICEF tried to solve Bangladesh's water shortage by drilling shallow tube wells across the country. These wells tapped into the layer of arsenic-rich sediment, transported eons before from the mountains upstream.
Today, tainted water threatens 70 million Indians, 65 million Bangladeshis and nearly 3 million Nepalis. Those who drink from contaminated wells often succumb to arsenic poisoning, their hands and feet blackening before they die.
UNICEF now works with the World Health Organization, along with other international and local relief agencies, to close down poisoned wells and drill others that are not tainted.
Meanwhile, villagers have developed a system of filtering water through three pots, which can remove most of the arsenic if done right.
Smith's arsenic-hunting tools are not complicated. They include a map; small bottles for taking water and sediment samples; lemon juice, which when squeezed in tainted water will cause arsenic to precipitate out; and endless flexibility for getting to inaccessible places.
With students and colleagues from Tribhuvan University in Kathmandu, Smith tackles the major rivers that flow down from Himalayan peaks. Systematically, the researchers take water and sediment samples from as many locations as possible.
When narrow gorges make road travel impossible, Smith signs up for a rafting trip with tourists. When Maoist guerrillas are active in one area, she moves a few provinces over and keeps collecting. When a friend from Colorado made a pilgrimage to gather holy water from the sacred Mount Kailash, she asked if he could spare a little for research. (He did.)
In Kathmandu, Boulder and Dallas, the information is gradually coming together in the first map of Nepal's arsenic rocks.
The map reveals the arsenic's path. Rivers today do not trace the same drainage patterns that they did millions of years ago. Geologic faults in the Himalayan foothills have diverted rivers to the east, so researchers must look west to see where the arsenic used to flow.
Slowly, Smith and her colleagues are starting to see patterns. Much of the arsenic, it turns out, comes from shale and ore deposits. As the Himalayas rose, squeezing the rocks within, the extreme heat and pressure formed minerals containing elements such as arsenic, nickel, cobalt, copper, iron and magnesium.
Then the Himalayas got so high that they interrupted the weather patterns over Asia, triggering the monsoon and washing out the arsenic. The groundwater contained so little oxygen, scientists suspect, that the arsenic dissolved in higher concentrations than it usually would.
This lethal combination of mountain-building and monsoon, says Smith, is found nowhere else in the world.
"It's phenomenal," she says.
The king of Nepal apparently agrees.
At a meeting of the Royal Nepali Academy of Science and Technology, the king asked to meet with Smith about her research. Clad in her best kurta surwal, she told him of the scientific fight against his country's poison.
Whether the relationship is with a king or a villager, she thinks she works well internationally because of her gypsy upbringing.
Her father, an Air Force pilot, took her through three high schools, in California, the Philippines and Virginia. She got a bachelor's degree in Colorado, a master's in Virginia, then started her doctorate in California a decade ago.
When Mobil hired her, she transferred to the University of Texas at Dallas. In December, she successfully defended her dissertation, which dealt with the Paradox Basin of southeast Utah.
Yet in a different sort of paradox, despite so many years working toward her doctorate, she doesn't want to do academic research. She'd rather teach.
Already, she has lined up several Nepali researchers and students to come to UTD this fall. They will work with faculty members Tom Brikowski and Matt Leybourne to analyze the arsenic and other chemicals present in Nepal's water.
But rather than seeing herself as a leader of this new effort, Smith says she's more of a facilitator.
"I love synergy," she says.
Her international background and her gender, she says, make her well-suited for putting together the best scientific team. Women, she believes, tend to work better in community settings, such as those needed to address the arsenic problem.
She often travels alone when doing research in remote locations. In Nepal, she taught herself to listen closely for the sounds of Maoist guerrillas, who have killed more than 7,000 people since 1996. Her only weapon, though, is the slingshot.
It came in handy once when hundreds of monkeys cornered her among cliffs. By hurling small stones at them, she bought herself time until passing fishermen could rescue her.
Even then her troubles weren't over. She had to make sure her backpack full of rocks and other samples didn't sink the boat.
© 2003, The Dallas Morning News. Displayed by permission.
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