Hartwell is part of an ongoing archaeological investigation of Early Man on the Pampas of Argentina. The project is headed by Dr. Eileen Johnson of Texas Tech University and Dr. Gustavo Politis of the Universidad Nacional de La Plata near Buenos Aires. "The focus is on comparing how people lived on the pampas grasslands, to how they lived on the grassy plains of North America," explains Hartwell. "The two environments are very similar, but there are some differences in how people lived and adapted."
For instance, spears and arrows were the primary weapons of North American plains people. But, archaeologists find relatively few arrowheads and spear points in South America. Hunters there relied instead on bola stones-stones tied to either end of a leather cord-to bag their quarry. "We're finding that people hunted with bolas from 10,000 years ago up to historic times, a sure sign that this was weapon technology that worked. The bola is perfectly suited to open, grassy areas like the Pampas-much easier to retrieve and much less likely to break than a spear or arrow. And so, we wonder why North American people in similar grassy plains rarely used it."
How people hunted, with bola stones, spears, or arrows is one part of the picture of humankind's beginnings. At the excavation site, La Moderna, the researchers are looking at what people hunted. Here, it seems, early hunters brought down one of the prehistoric world's monstrous megamammals: a long-vanished giant cousin of the armadillo called a glyptodon. It's a significant find because until recently, most researchers believed that the glyptodon had died out before man arrived in the New World. Hartwell says the bones of the beast have been dated at about 6,500 years old-a number so surprisingly young in archaeological terms that it may just be a mistake. "We're in the process of dating sediment samples from the site to see how they correlate with the dates from the glyptodon bones. That will help us decide if they're accurate."
While La Moderna gives a glimpse of how these early people managed to live, another site, Arroyo Seco, reveals how they died. The researchers have so far uncovered 25 ritualistic human burials, some including beads, necklaces, and the other belongings of the deceased. In some cases, says Hartwell, the cause of death was painfully obvious. "One poor guy had about five spear points stuck in him."
But perhaps more intriguing than the actual remains at Arroyo Seco is the length of time they've laid there. The graves range in age from 5,000 to 8,500 years, meaning that the site was used for burials for at least 3,500 years. According to Hartwell, this came as something of a surprise. "These people were hunters and gatherers who had to move with their food supply. But this site, used for burials for such a long period, indicates much more stability."
And so the detective work continues, as Hartwell and his colleagues uncover the clues to how the ancients lived on the Argentinean grasslands. But, the Pampas story is just one small piece of a larger puzzle: how and when did human beings, with their beginnings an ocean and a continent away, come to people in the Americas. The predominant theory holds that human beings crossed a land bridge at the Bering Strait and worked their way south, meaning the oldest populations would be found in North America. "But some South American sites are dating back over 11,000 years," says Hartwell, "rivaling the oldest in North America. It may be a matter of not yet looking in the right places, but it also raises some questions about the peopling of the Americas in general."
Samples from the Argentinian sites are now being processed and dated in DRI's radiocarbon laboratory. Hartwell hopes to return to Argentina with Johnson and Politis in the near future, and perhaps uncover a few more pieces of the past. -Jackie Allen
But, if the Cold War is dead, its epitaph surely reads "gone but not forgotten." Because, while we produced and tested thousands of nuclear weapons, we also made nuclear waste. Contaminated buildings from uranium processing plants, equipment exposed to radiation during weapons production, and radioactive soil from the sites where weapons were tested-this "defense" waste is the environmental legacy of the Cold War, and we're still cleaning it up.
Some of this defense waste is categorized as low-level nuclear waste (see page 5). It doesn't have to be locked away for 10,000 years, but it can't go into a local landfill, either. Low-level waste must be put in approved disposal sites like Frenchman Flat on the Nevada Test Site, which lies about 65 miles north of Las Vegas. Concerned about maintaining the groundwater quality in the area, the U.S. Department of Energy (DOE) asked DRI scientists Dr. Scott Tyler, Dr. Richard French, Bill Albright, Jenny Chapman, Sam Hokett and Craig Shadel to take a close look at Frenchman Flat for any possibility of contamination from the buried waste.
The waste sent to Frenchman Flat is packaged in steel containers and plywood boxes, stacked, and then buried in trenches about 22 to 40 feet deep. To determine the potential for groundwater contamination, Tyler and his team are looking at the unsaturated zone: the 700 or so feet of soil under the buried waste and above the water table. Not much rainfall reaches the unsaturated zone of Frenchman Flat. The desert sun evaporates it at the surface, and thirsty desert plants absorb it from below. This is exactly why many consider a desertenvironment like Nevada's to be an ideal place to bury radioactive and other hazardous wastes: there's less chance of surface water percolating through the waste, picking up contaminants, and reaching groundwater. But, some water does reach the unsaturated zone. By analyzing that water, scientists can determine how long ago it dropped from the clouds and began traveling through the desert soil. In short, they can tell us how old it is.
So far, the results of the study have brought DOE good news in terms of waste disposal. It appears the water in Frenchman Flat's unsaturated zone is old-as much as 120,000 years old-meaning it takes a long, long time for water to move from the surface to the water table. In this amount of time, any dangerous amounts of contamination would probably have dissipated by radioactive decay, or been absorbed in the soil itself.
The next step, says Tyler, is ensuring that the filled trenches remain stable and safe. "We have a group of DRI people working with other scientists on the Nevada Test Site on a design for a covering that will mimic the natural landscape and protect the waste area. We have to take into consideration vegetation, flood protection, soil erosion, drainage, and the possibility of burrowing animals-it really takes a whole team."
That team has helped design a cover that Albright describes: "There is six feet of native soil on top with a bit of gravel mixed in. The idea is that the gravel will migrate to the surface over time, creating a desert pavement to limit erosion of the cover by wind and rain. Below that is a cemented soil layer. It has low permeability, gives solid support for the overlying soil, and reduces the chances of roots or animals entering the waste cells. Rocks and berms are around the edges for flood protection, and the whole area is sloped just slightly for drainage." Once it's covered, monitoring wells distributed throughout the filled pits will let scientists sample the air and soil below the waste to see if radioactive materials are moving out of the containers.
Tyler will be monitoring Frenchman Flat's unsaturated zone for the next couple of years, tracking any water that does move through the area, and determining if certain conditions like increased rainfall, settling of the waste trench, or re-vegetation might make the water move more quickly. So far, he says it appears that if you've got to have a place to put radioactive waste, Frenchman Flat is a safe place to put it.
Like it or not, technology comes with a price tag. And one cost of the Cold War-some would say the price of security-is the waste associated with nuclear weapons technology. As yet, there's no perfect disposal solution, no way to make the waste disappear. Until there is, scientists like Tyler will be keeping close tabs on disposal sites like Frenchman Flat.-Jackie Allen
Water doesn't have a taste, a scent, or a color, but it does have naturally occurring radioactive isotopes. An isotope is an element, such as carbon and chlorine, with one or more extra neutrons in its nucleus. Each radioactive isotope decays at a known rate. To date groundwater, scientists determine how much of an isotope (such as carbon-14) is still present, then knowing its rate of decay, calculate how long the water has been in the soil or aquifer. They also get dating information by looking at the concentration of isotopes like carbon-14 and chorine-36 in the groundwater, since their concentrations have varied over time due to changes in the earth's magnetic field.
The water molecule itself reveals clues about its age. For example, in rainwater, the ratio of hydrogen to its isotope, deuterium, is strongly controlled by the atmosphere's temperature. During cold periods like the last glacial period, rainfall had less deuterium than it does today. That means ground-water showing this "isotopic depletion" must have fallen at least 10,000 to 15,000 years ago, when southern Nevada was five to ten degrees Fahrenheit cooler than today.
In comparison to high-level radioactive waste, the radioactive material in low-level waste is generally short-lived or in low concentrations, posing less of a threat to human health and the environment. Commercially, it's generated from nuclear power plant operations, research activities, and the medical field. All kinds of things-from test tubes to tools-which have been contaminated by radiation may be classified as low-level waste. Some medical diagnostic procedures can produce low-level waste, as can cancer research, and the treatment of a thyroid condition. The government produces low-level defense waste from weapons production and the cleanup of contaminated sites. It may be soil removed from the site of a nuclear weapons test, or the contaminated planks of a building that stood in a uranium processing plant.
Since the passage of the Low Level Radioactive Waste Policy Act in 1980, the states are responsible for disposing of their own commercially generated low-level waste. Nevada's low-level waste-including that generated by university research and by construction and mining activities-is sent to a site in Richland, Washington. Currently, there are only two other sites in the country that are receiving commercial low-level waste. One is in Barnwell, South Carolina, and the other is in the desert west of Salt Lake City, Utah.
The U.S. Department of Energy is responsible for the disposal of all high-level nuclear waste and its own defense waste. Frenchman Flat is one of several low-level defense waste disposal facilities around the country. Right now, most high-level commercial waste is in temporary storage at various reactor sites, while studies of a proposed permanent repository at Yucca Mountain in southern Nevada continue. Final disposal solutions for high-level defense waste are still in the planning stages.
Dr. Jack Gillies, a DRI specialist in dust suspension, explains that unpaved roads, construction sites, and other areas where the desert surface has been broken or disturbed by human activities are potential sources of fugitive dust.
In the Las Vegas Valley, Nevada, fugitive dust is suspected to be one of the main culprits in the valley's periodic violation of the "PM-10" federal particulate standards. Other potential culprits are cement and gravel operations, fireplace smoke, and auto emissions. "PM-10" refers to invisible airborne particles that are ten micrometers or less in diameter. A micrometer is one-millionth of a meter long, or about one-fiftieth of the diameter of a human hair. These tiny particles can be inhaled and become lodged in human lungs, creating breathing problems and irritating other existing lung ailments.
Clark County officials, who are responsible for Las Vegas Valley's air quality programs, are taking steps to reduce this health threat from fugitive dust. Desert Research Institute scientists are working with Clark County's comprehensive planning and health departments on a key step: tracking down the "fugitives." DRI, a world leader in air quality research, helped pioneer the "fingerprinting" technique its researchers are using to connect the particles with the places they "escaped" from.
Dr. Judy Chow, DRI's principal investigator for the study, says the Las Vegas Valley has been averaging about three PM-10 violations a year for the last six years, and one of the county's sampling sites has registered annual averages above allowed particulate levels.
Besides the possible health consequences for southern Nevada residents, failure to comply with federal standards can result in a loss of federal funds for highway construction and other projects, says Will Cates, Clark County's principal planner and head of its PM-10 efforts. He adds that by 1997 the county must show the federal government how it plans to comply with air quality regulations. The southern Nevada region has grown explosively in the past two decades, from a population of a couple hundred thousand to more than a million. That means lots of new roads waiting to be paved, square miles of commercial and residential construction, and a lot of disturbed dirt just waiting for a windy day. Health regulations require anyone breaking up the surface crust or otherwise producing dust to suppress the dust on their sites, but how much each of these sources contribute to the area's overall dust problem hasn't been determined. That's where DRI comes in.
To gather the project's data, Dr. Mark Green, a DRI atmospheric scientist in Las Vegas, forecasts likely periods of high winds. A team of Green's DRI colleagues, on standby for the wind alert, go out and install 60 air sampling devices in 30 locations in the valley. "Ideally, we'd like to be able to get the samplers up a day or two ahead of the windy period, and leave them up a day or two after, so we have a clear comparison between the two conditions," Green explains. Two other samplers, which run for 24 hours every six days, make long-term measurements of contributions of all sources of PM-10 particles.
The DRI team, which also includes Dr. John Watson, Dr. Frank Divita, Dick Egami, Steve Schmidt, Barbara Hinsvark, Cliff Frazier, and Stacy Brown, began the project in January. So far, they've sampled airborne dust on 21 days, involving three windy periods in April, May and June, and one calm period in September.
In addition to sampling dust storms, the DRI crew will collect settled dust and dirt from the valley's streets, sifting out the larger particles which aren't relevant, and analyzing the size composition of the smaller particles to see how much is likely to be resuspended by traffic or wind. Then, in what amounts to a sophisticated air pollution fingerprinting process, DRI will do laboratory analyses and statistical modeling to determine how much of the total PM-10 material is coming from each type of source in the valley.
Before Clark County can design a strategy to reduce the dust and meet the federal standard, it needs the results of DRI's study so it can put its efforts in the right places, Cates explains. The strategy could include paying more attention to weather forecasts of windy conditions, more intensive watering on cleared land, chemically stabilizing or paving dirt roads, and "just-in-time" surface clearing schedules that only expose areas planned for immediate construction activities.
It will be late next summer before DRI's work is completed and the dusty fugitives are positively identified. Then, Clark County begins the major task of implementing its strategy and showing measurable results: healthier air and better visibility during the desert's windy days.-John Doherty
Besides several studies for Nevada, DRI's air quality scientists have done research in Dallas, Texas; Pittsburgh, Pennsylvania; Ohio River Valley; Phoenix and Tucson, Arizona; Santa Barbara, Los Angeles Basin, South Coast Area, North Coast, Mammoth and Owens Lakes, San Joaquin Valley, San Francisco Bay Area, Sacramento, and Sonoma County, California; Denver, Colorado; national parks in the Desert Southwest; Sierra Nevada; West Virginia; Mt. Zirkel, Colorado; Southeast Texas Coast; Utah; Puget Sound, Washington; Hawaii; USA/Mexico border; Philippines; Puerto Rico;Taipei, Taiwan; Vancouver, British Columbia, Canada; Santiago, Chile; Cairo, Egypt; Bangkok, Thailand; Antarctica; and Johannesburg, South Africa.
"Through geochemistry and isotopic chemistry, we've found a lot of our groundwater was recharged under much colder and wetter climate conditions than we have today," Chapman says. "This could mean that our water supplies are not being replaced as fast as they're being used in today's hotter and drier climate." Chapman's research also helps track down groundwater pollution. Water lying deep underground can be contaminated by many activities, including chemical spills and hazardous waste storage. If polluted groundwater is near a well, it can threaten human health. "Understanding the groundwater system is crucial when you're evaluating the risk from contamination," the DRI hydrogeologist explains. "For example, we can find out how fast the contaminated water is moving, and if it's moving toward wells that supply drinking water."
Recently, she assessed the risk posed by groundwater contamination in two former nuclear testing sites in south-central and west-central Nevada. Also, Chapman helped research the risk of contamination from the low-level radioactive waste disposal site on Frenchman Flat at the Nevada Test Site (see related article on page 3.)
She earned a bachelor's degree in geology from Sul Ross State University in Alpine, Texas, in 1981, and a master's degree in geology with a specialization in hydrology from the University of Texas at Austin in 1984. Before joining DRI in 1988, she held hydrogeologist positions with the State of New Mexico's Environmental Evaluation Group and the Radian Corporation. Chapman and her husband, Barry, have a three-year-old daughter and a one-year-old son.
Picone, who joined the institute almost three years ago, works in DRI's one-of-a-kind Great Basin Environmental Research Laboratory. He, Ball, and fellow DRI scientists are researching how plants will respond to the high levels of atmospheric carbon dioxide predicted to exist 50 years from now.
Little is known about how plants may react to changing conditions such as shifts in light, carbon dioxide levels, water consumption, and soil respiration. "We're already discovering that things we assumed to be true no longer hold," Picone says. "The next step is to see if we can reproduce our results outside of the lab."
Picone earned his bachelor's degree in engineering from Arizona State University in 1979, and his master's degree in mathematics from the University of Iowa in 1982. He earned his Ph.D. in physiology and biophysics from the University of Cincinnati in 1989.Picone says that there are many parallels in plant and animal physiology, and he is optimistic about what he has left to learn. "Science is science," he adds. "Everything works according to the same laws of nature and those laws can be applied in every field."
When not in the lab, Picone enjoys mountain biking and sailing with his wife, Tania. Their favorite areas include Lake Tahoe, Peavine Mountain, and anywhere wildflowers are in bloom.
Johnson's research has included studies on the effects of acid deposition, fertilization, harvesting, municipal sludge application, and carbon dioxide enrichment on soils and forest ecosystems. He came to DRI from Oak Ridge National Laboratory in 1989, and currently holds a joint appointment as professor of forest soils, environmental and resource science at the University of Nevada, Reno.
Johnson served as associate editor for the Journal of Environmental Quality from 1985 to 1990, and has been associate editor for the Soil Science Society of America Journal since 1993. He has served on numerous advisory committees, been an invited speaker at several international conferences, authored more than 75 peer-reviewed publications, and edited three books.
Hess is a member of the graduate faculty at both the University of Nevada, Reno and and the University of Nevada, Las Vegas. He joined DRI in 1974 and became Water Resources Center director in 1989. He maintains an active research program in hydrology, hydrogeology, and isotope hydrology.
The Maxey Fellowship is endowed through the generosity of DRI Research Foundation Trustee Emerita Elizabeth West Stout in honor of the late George Burke Maxey, who directed DRI's Water Resources Center from 1967 until his death in 1977. Maxey also founded the University of Nevada's Ph.D. program in hydrology.
In October, DRI scientists Judith Lancaster, Dr. Dave Mouat and Dr. Alvaro Crosta (on sabbatical leave from the University of Campinas, Brazil) will visit Ceara to help organize a Latin American Desertification workshop. "We'll also be creating a framework for collaborative research," Lancaster says. "Our initial talks have developed into a multifaceted approach involving basic research, institutional development, education, technical training, and information dissemination."
The site is significant scientifically, he explains, because it is located on a ridge several hundred feet above the Virgin River, rather than along the riverbank for easy irrigation, as was typical. The Hurricane pueblo is believed to represent the westernmost expansion of the Anasazi culture. The five-week, eight-hour-a-day field school attracted 11 UNLV students and several volunteers from the Utah Archaeological Society. Most of the funding was provided by the U.S. Department of Energy's Yucca Mountain Project Office.
Jerry Cail is president of Banner Printing, which has a broad base of national customers, and serves local and international markets as well. Banner has 10 presses, a full range of color printing, and full bindery services. A Reno resident for more than 20 years, Cail is an avid supporter of local children's programs and Nevada Wolf Pack athletics. Cail is a member of DRI's Corporate Giving Club.
Tyrus Cobb, son of Reno Gazette-Journal columnist Ty Cobb, is the president and CEO of Yosemite National Institutes. YNI provides distinctive science/environmental education for 30,000 people a year at its three institutes in Yosemite, Olympic National Parks, and the Marin Headlands. Previously he served as a special assistant and adviser to President Bush.
Ian Mackinlay is president of Ian Mackinlay Architecture, Inc., in San Francisco, California. Licensed in numerous states and a resident of Incline Village, Mackinlay is an expert in cold region architecture. His experience ranges from hotels to schools to laboratories, and he is the recipient of more than 50 awards for architectural design excellence.
Robert Quenon is a mining consultant with a worldwide client base. He consults with numerous mining companies, government, and civic groups, and sits on many advisory boards. Much of Quenon's work has taken him to the former Soviet Union and Eastern European countries. He lives in St. Louis, Missouri, and is currently chairman of the Federal Reserve Bank of St. Louis.
Emeritus status was also awarded to trustees and long-time supporters Elizabeth West Stout And Aileen Maki
dri news is published quarterly by the Desert Research Institute, a nonprofit, statewide division of the University and Community College System of Nevada.