Stark images of earth from 135 miles away can help health officials in Mexico pinpoint outbreaks of malaria before they occur, distinguish deadly oil spills from the viscous sheen produced by plankton, and warn people when the crops they eat might contain radiation. These are but a few of the actual and expected pay-offs from the recent shuttle flights run by the National Aeronautics and Space Administration (NASA) under the rubric of Mission to Planet Earth (MTPE).
The mission is a campaign to study the earth as a global environmental system that will continue into the 21st century. Some of the program's signature flights last year are yielding tangible results for scientists interested in the relationship between environmental change and human health, said Robert Harris, director of the science division of MTPE at NASA headquarters in Washington.
Eye in the Sky. NASA radar images of the Virunga volcano chain along the borders of Zaire, Rwanda, and Uganda help scientists tell if the vegetation will support the world's last 650 mountain gorillas and if eruptions may threaten area villages.
"We need to devote most of 1995 to analyzing mountains of data from highly successful MTPE shuttle flights in 1994," said Harris, who thinks the latest MTPE data can impress Congress and the public into supporting the revamped, streamlined program. Harris points, for example, to data from two 10-day shuttle flights in April and October that revealed the earth as it might be seen without vegetation and scoured its lower atmosphere for evidence of deterioration. The flights, called Space Radar Laboratory I and II, featured two MTPE instruments: the U.S.-German-Italian Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR), and a device known as MAPS (Measurement of Air Pollution from Space).
The $400 million radar, the most sophisticated of its kind, has the ability to make measurements of the globe over virtually any region at any time, regardless of weather conditions. It can "see" through vegetation cover to map the earth's crust, oceans, and watersheds. "Our main goal is to monitor the earth's health and see how it is doing," said the project's chief scientist, Diane Evans, of the Jet Propulsion Laboratory. The radar can forecast natural disasters by tracking pools of water that form in depressions on a volcano's slope, and can pick out natural pollutants, like algae scum, from man-made hazards like oil spills. It can trace environmental disasters, such as damage to wetlands left by the Chernobyl nuclear power plant explosion.
The data can even predict the outbreak of some diseases, said Evans. University of California at Fresno Professor Jack Paris uses radar data to develop models to predict when stagnant water will produce mosquitoes that carry malaria. So far, he and other researchers have forecast conditions in both Belize and on Mexico's Yucatan Peninsula that produced outbreaks. Such information can also be used to predict outbreaks of yellow fever and snail-borne schistosomiasis, a parasitic infection that is a major health problem in Asia, Africa, and South America. "It's an incredibly useful resource for developing countries," Paris said.
The MAPS instrument measures the global distribution of carbon monoxide in the lower atmosphere. Measuring carbon monoxide indicates how well the atmosphere can cleanse itself of greenhouse gases that can increase the atmosphere's temperature, said project scientist Vicky Connors, of NASA's Langley Research Center. It also assesses loss of ozone protection against ultraviolet radiation, she said. "If ozone is depleted, as we see it can be in the southern hemisphere, UV increases can result in increased skin cancer, but also in DNA damage in crop plants--a very compelling concern." New data released by NASA in December and again in January confirms that the atmosphere is slowly warming and that seas are rising one-tenth of an inch each year. The findings combine Space Radar Laboratory flights data with other information, including information from a third MTPE shuttle flight last year, the Atmospheric Laboratory for Applications and Science (ATLAS).
So far, the MAPS instrument is slated to fly on a satellite in two years, said Harris, but the future of SIR-C/X-SAR is uncertain. It will have to compete with other MTPE instruments vying to fly on a small platform in 1998. Although NASA spent $1.2 billion on the MTPE last year and is expected to spend another $1.3 billion this year, its scope has been considerably scaled down. Now, instead of grand space platforms from which arrays of instruments would fly by the year 2000, smaller, cheaper platforms are being designed to appeal to Congress, which slashed the initiative three times this decade--from $17 billion to $7.5 billion--saying it was too risky and unjustifiably expensive. Harris is worried it will happen again: "Any more cuts and we will drastically reduce our objectives and probably lose some international partners who are helping us fund it now."
Farmers in Ontario are spraying smaller amounts of pesticides on their crops than in the past. From 1983 to 1993, pesticide use dropped by a dramatic 28.3%, according to the Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA). By comparison, pesticide use in the United States fell 15% between 1982 and 1992. Under the Food Systems 2002 project, OMAFRA has worked with farmers and agricultural and environmental groups since 1987 to cut pesticide use in half by the year 2002.
Spraying for certain. Properly calibrated spraying equipment helps farmers ensure minimum amounts of pesticides necessary are used.
Declining North American pesticide use resulted, in part, from the application of environmentally "safer" chemicals, although greater amounts of such chemicals might be necessary to achieve the same effect. Today, Ontario farmers use one-third as much atrazine on corn crops to control quackgrass as they did 10 years ago. This one million kilogram decrease represents nearly half of Ontario's total reduction in pesticide use. Many Ontario growers, concerned about atrazine's environmental persistence, eliminated fall applications. On many farms, newer, short-lived herbicides, sprayed at rates of grams per acre rather than kilograms per acre, have replaced atrazine, said Ken Hough of the Ontario Corn Producers Association. There is evidence of a similar trend in the United States, where reduced herbicide use accounts for over 60% of the total decline in pesticide use.
In the early 1980s, the farming community's rising concern about escalating pesticide applications prompted the Ontario government to support lower pesticide use, said Jeff Wilson, chairman of AGCare (Agricultural Groups Concerned About Resources and the Environment), which represents 45,000 growers in Ontario. "It was an evolutionary process, beginning with initiatives from growers," said Wilson, "without a Big Brother or heavy-hand syndrome." Bruce Archibald, manager of OMAFRA's Environmental Health Program, concurs. "It was a win-win situation, with a shift in thinking on the part of the growers and the government providing resources."
Archibald credits much of Ontario's reduced pesticide use to the certification program for purchasing pesticides. Initiated as a voluntary program in 1988, certification became mandatory throughout Ontario in 1991 at the growers' request. To become certified, growers attend a full-day course on proper label reading, mixing, and applying pesticides, and pass an exam every three years. Before this awareness-raising initiative, said Wilson, farmers applied up to 20% more pesticide to their crops than necessary because of poorly calibrated spraying equipment. In the United States, applying a "restricted use" pesticide requires a license. However, many commonly used pesticides are not restricted, and licensing requirements, developed by each state, vary throughout the country.
Ontario's certification course also introduces the principles of integrated pest management (IPM), such as crop rotation, mechanical pest removal, use of natural pest predators, and targeted use of pesticides, to help Ontario farmers manage pests more efficiently. During the growing season, farmers using IPM monitor their crops for the appearance of pests or weeds. When pest infestation exceeds a threshold level, the farmer applies a pesticide specifically targeted for that pest. This approach contrasts with traditional methods of applying a broad-spectrum pesticide several times a year.
Wilson, a potato and apple grower, pays $14 an acre to have scouts monitor his crops for pests. A pesticide specialist provided by OMAFRA sets threshold criteria and advises him on the timing of pesticide applications. Using this service has eliminated two pesticide sprayings per growing season, which, he said, saves money and protects the soil and water from excess toxic chemicals.
In 1993, the Clinton administration set a goal of implementing IPM practices on 75% of U.S. cropland by the year 2000. By the end of the 1993 fiscal year, formal integrated crop management agreements (which integrate IPM with soil conservation and nutrient management) had been implemented between the USDA and 1092 farms, covering 176,000 acres. Although this represents only one-tenth of 1% of the nation's total cropland, a survey by the U.S. Department of Agriculture indicates that at least some IPM practices are being used on a large portion of the farm acreage in America. The results of this survey, released in September of 1994 in an agricultural information bulletin, show that some form of IPM is being used on 60% of planted acreage of fruits and vegetables and 75- 80% of field crop (corn and potato) acreage.
Historically, the USDA taught farmers to use pesticides as an insurance policy for maintaining crop yields. Getting farmers to change their crop protection methods requires re-education, said Betty Marose, an IPM specialist and Maryland Cooperative Extension agent. "A lot can be done if you have the resources for an extension agent to demonstrate these methods," said Marose, "but it requires time and money." Unfortunately, funding for IPM education and implementation has remained level for the past 10 years.
Ontario's pesticide-container recycling program also contributed to reduced pesticide use. When containers are triple-rinsed before recycling, the rinse, containing as much pesticide as 6% of the tank volume, is saved and applied to crops. A similar U.S. program, initiated by pesticide vendors in 1992, now has participation in 45 states.
With seven years to go, Ontario is well on its way to meeting the Food Systems 2002 goal. Future reductions in pesticide use will be fine tuning, Wilson says, which depends on new research and technology.
Bottled water is one of the fastest-growing beverages on the market. In 1992, consumption of bottled water surpassed that of tea, wine, liquor, powdered drinks, and juice. In 1993, 2,257.7 million gallons of bottled water were sold in the United States, according to Lisa Prats, vice president of the International Bottled Water Association, the trade association of the bottled water industry. Consumers of bottled water cite taste as their primary reason for buying bottled water, but other reasons are safety and concerns about chemicals in tap water, says Prats. The question is, is bottled water worth the difference in cost, at an average cost of 700 times more than plain tap water?
A majority of Americans say they are pleased with the quality of the water that comes from their taps, according to a 1993 national survey on how Americans rate their drinking water by the American Water Works Association. As reported in the winter 1994 issue of On Tap, the AWWA survey found that 62% of Americans rate the quality of their drinking water as good (41%) or excellent (21%), while 75% believe that the water in their local community meets (57%) or exceeds (18%) the federal standards for quality and safety. Still, the AWWA survey found that 43% of respondents drink bottled water at least some of the time, although tap water is still their main source of drinking water, and 8% use bottled water exclusively.
Strict regulations govern both bottled and tap water industries. Unlike well water, which isn't subject to regulation, public water supplies are regulated by the EPA. Bottled water, on the other hand, is considered a food, and is regulated by the Food and Drug Administration. In 1989, the Environmental Policy Institute concluded that the "regulations for bottled water were not on par with those for tap water," say Linda Allen and Jeannie Darby of the University of California-Davis in an April 1994 article in the Journal of Environmental Health. In addition, regulations for tap and bottled water are not standardized: tap water has uniform national regulations, but "bottled water is still subject to federal regulations with limited applicability and inconsistent state regulations," say Allen and Darby.
In 1989 the Environmental Policy Institute concluded that bottled water is not necessarily any safer than tap water. In fact, EPI says that storage of bottled water, often for weeks or months at room temperature and higher, promotes bacterial growth in the water. Elevated levels of bacteria in water can cause health problems for infants, the elderly, and immunocompromised people. Still, Stephen Schaub, senior microbiologist in the EPA's Office of Groundwater and Drinking Water, stresses that although studies are inconclusive on the issue, bacteria in bottled water doesn't seem to be a significant problem.
However, an incident in February 1990, in which benzene, a chemical known to cause cancer in humans, was detected in bottles of Perrier at levels that exceeded by four times the EPA standards for tap water, points out that bottled water may have other problems. Perrier recalled more than 170 million bottles as a result of the contamination, and the incident prompted the U.S. General Accounting Office to charge the FDA with failing to set "adequate safety standards for chemical contamination of bottled water."
In 1994, the FDA passed regulations that impose the same standards on bottled water as the EPA imposes on tap water. An exception is lead: lead content may not exceed 5 parts per billion in bottled water, whereas EPA limits lead in tap water to 15 parts per billion. Bottled water may help to bypass other potential problems brought about by the practice of public water suppliers of adding chlorine to drinking water to remove bacteria. Although chlorine kills bacteria effectively, it can react with organic matter in water to form by-products such as trihalomethanes which have been linked to bladder and rectal cancers. Chlorine is not used as a disinfectant in bottled water, according to Prats.
Despite almost half (49%) of the respondents to the AWWA survey saying they believe bottled and tap water to be equal in quality, 37% responded that bottled water is safer and healthier to drink than tap water, as opposed to only 10% who said the opposite, a perception most chalk up to clever advertising by the bottled water industry.
Americans drink bottled water primarily for aesthetic reasons: the taste, smell, and appearance of the water. Tap water supplies are often treated with chlorine, which can leave an aftertaste or odor. Bottled water, on the other hand, is usually treated by ozonation and filtration, processes that leave no aftertaste. Besides taste considerations, the EPA says that drinking bottled water is appropriate when the levels of contaminants in the local water supply exceed health standards, and when household problems, such as lead in the pipes, can cause contamination. Otherwise, researchers argue that bottled water just isn't worth the price, especially considering that it must be purchased, transported, and stored by the consumer. Canadian water researcher Pierre Payment, of the Armand-Frappier Institute, said in an article by the Associated Press that municipalities should advertise the quality of their water the way bottled water companies do, because "North American tap water is the best you can get."
Apoptosis is an ancient Greek word meaning "the falling off" of petals from flowers or leaves from trees. In modern scientific terms, apoptosis refers to the natural or programmed death of cells, as opposed to death caused by injury or necrosis. The failure of programmed cell death to occur has been linked to a variety of illnesses including cancer, dementia, and even AIDS. NIEHS scientist John Cidlowski has been exploring pathways by which apoptosis occurs in hopes of developing screens to reveal how environmental agents affect this process.
"I liken apoptosis to editing," says Cidlowski. "It's what causes us to lose the webbing between our fetal fingers and toes. It's also responsible for male pattern baldness in adults. It even has a suspected role in Alzheimer's disease."
Apoptosis is an energy-demanding process, requiring ATP and the activation of an endonuclease that degrades the chromosomal DNA into small particles. This process culminates in fragmentation of the cell into discrete membrane-bound apoptic bodies that are engulfed by surrounding cells and macrophages.
In contrast, necrosis occurs in response to a variety of harmful conditions and toxic substances. It typically affects groups of contiguous cells, and an inflammatory reaction usually develops in the adjacent viable tissue in response to the release of cellular debris.
There are numerous pathways by which apoptosis can occur, as evidenced by the diversity of signals that stimulate the process. Cidlowski estimates there are 400-500 different ways to stimulate apoptosis, and different stimulants yield varying responses in different cell types. "In some cells, the oncogene c-myc is an inducer of apoptosis, yet in other cells it prevents it," Cidlowski says. "Our picture of the signal transduction pathways is not clear. They are going to be cell specific."
Cidlowski has spent the past 16 years researching apoptosis at the University of Vermont and the University of North Carolina, where he focused on three areas: how apoptosis is induced by stress; physiological adaptations to stress, particularly the role of glucocorticoid receptors, in activating apoptosis in lymphocytes and maintaining homeostasis in the rest of the body; and the role of nutrients, especially vitamins, and gene expression in apoptosis.
It is known that certain environmental chemicals, including dioxins, heavy metals, and peroxides, lead to apoptosis in a variety of cells. At the NIEHS, Cidlowski is testing various chemicals to see what components of apoptosis pathways they activate. "We are analyzing the motors of apoptosis," he says. "We are focusing on the enzymes and genes that lead to cell shrinkage, DNA fragmentation, chromatin condensation, protein and RNA turnover, and inhibitors of apoptosis."
The role of apoptosis in cancer, AIDS, Alzheimer's, and other diseases has spawned an explosion of research on the subject. Cidlowski estimates there were as many as 1,000 articles on apoptosis published last year, as opposed to perhaps 50 papers a decade ago. But he cautions against the implication that apoptosis is the answer to everything. "There may be other mechanisms of cell death," Cidlowski says. We are testing whether apoptosis is the physiological counterbalance to mitosis."
Although Cidlowski emphasizes that he and his colleagues are not cancer researchers, some of their research is of particular interest to cancer researchers, such as analysis of the effects of various chemicals, including steroids, metabolic poisons, and immunosuppressants, on apoptosis in the immune system. It was originally thought that such chemicals simply inhibited cell replication. Cidlowski's team has been able to separate inhibition of replication from cell death and has proven that these chemicals act on cancers by inducing apoptosis.
Many chemotherapeutics act by stimulating apoptosis. A major problem with this treatment, however, is that over time cells tend to develop resistance to some chemicals. Cidlowski theorizes that this resistance may result from a loss in the capacity of the tumors to undergo apoptosis. If this theory is true, it places in doubt the prospect that chemotherapy can be refined to be the ultimate treatment for cancer. "We don't know what causes this resistance," Cidlowski says. "If cells lose one of the fundamental motors of apoptosis, it may be difficult to bypass resistance to chemotherapy. Then we'll have to look to new alternatives."
Cidlowski's goal is to define the key components in apoptosis and develop screens for these components in tumors. Then, he says, "we can . . . see if key components remain functional and, if so, we can proceed with alternative inducers of apoptosis."
For many, the combination of Native Americans and fire conjures images of pow-wows around a communal blaze. For the 60% of Navajo households that rely on wood or coal-burning stoves as their source of heating and cooking, one reality of that combination is a variety of respiratory illnesses caused by smoke from leaking stoves. However, researchers have discovered a solution in the form of an alternative fuel that burns more slowly than wood and produces almost no smoke: the root of the buffalo gourd.
Digging for answers. Shultz (above left) examines roots with farm foreman. Women and children near Mexico City test ease of gathering roots (right).
Eugene B. Shultz Jr., a professor of technology and human affairs at Washington University in St. Louis, Missouri, has spent a large part of his career looking for alternatives to wood as fuel in dry, deforested lands, primarily Third World countries. It was while distilling the roots of the buffalo gourd (Cucurbita foetidissima) to make ethanol, not burning them, that Shultz happened upon them as a source of fuel. Shultz explains that the person operating the still had been given too many roots and so threw them out to rot, expecting to take them home for compost. The roots did not rot, the operator reported to Shultz, but dried in the sun "as hard as wood." The revelation prompted Shultz to study the roots as alternatives to wood fuel.
With funding from Western Regional Biomass Energy Program, a program of the U.S. Department of Energy, two projects were begun last May: one at Washington University to test how the buffalo gourd root performed as a fuel, and one at New Mexico State University to test whether it could be grown as a solid fuel crop.
Results of Shultz's studies showed that the roots burn one-third as fast as wood and produce almost no smoke. When dried completely in the sun, the roots contain almost no water, a necessary component of smoke, unlike wood that retains almost 20% moisture even after drying. In addition, unlike wood, the roots contain almost no lignin, the source of by-products of incomplete combustion including carcinogens and respiratory irritants. These two factors make the roots, native to New Mexico, a potential solution to a persistent and devastating health threat to the state's Native American population; respiratory illnesses such as asthma and interstitial lung disease make up the third greatest cause of death among the Navajo. A 1990 study at the Tuba City (Arizona) Indian Hospital found that Navajo children under the age of two living in homes with wood/coal stoves were five times more likely to develop acute lower respiratory tract infections than children in homes without such heating systems. Because the Navajo live in a relatively pristine environment, free from pollution, and because only 10% of Navajos smoke, medical personnel were baffled by the magnitude of the problem of respiratory illnesses among the population. Said Louise Able, a physician with the Indian Health Service, in an article by the Associated Press, "When I began looking at it, I realized that the one common factor was chronic smoke inhalation leading to chronic respiratory illness . . ."
Although the buffalo gourd grows in relative abundance in the low-lying areas of New Mexico, the mile-high plateau of most of the Navajo Nation is too arid to support the plant. The challenge for researchers at the New Mexico State University Research Station was to see if the plant could be coaxed with irrigation to grow at that elevation. Researchers found that, with irrigation, the plant actually thrives in the climate, and crop yields exceeded those previously published in the literature. Although it is difficult to estimate needs because family sizes vary, it might take as little as one-half to one acre of growing area to supply a family with all of their fuel needs. And because the roots are lightweight, even children can help to harvest and handle them.
The potential problem with using the roots as fuels is cost. Although much healthier than wood or coal, the roots would have to compete with the free supplies of coal often provided to the Navajo by companies that mine on Indian land. "The roots would have to be subsidized," says Shultz, "although 'subsidy' may be considered a bad word in today's political climate, so we may have to find another word." According to Shultz, the problem comes down to the fact that because 57% of Navajos live below the poverty line, buying new stoves that don't leak smoke is out of the question for the majority of them, so an alternative fuel only makes sense. "You can solve the problem by buying them decent stoves or by providing them with cleaner fuel." Either way, continues Shultz, the health of the Navajo is the compelling factor. "These people don't deserve these illnesses."
Rootfuel studies are also being conducted in Mexico, Brazil, Zimbabwe, and India. Due to increasing deforestation, it is estimated that by the year 2000, 2.7 billion people worldwide will have inadequate access to wood fuel.
April 22 marks the 25th anniversary of Earth Day. A World Wide Web site allows Internet surfers to explore and retrieve information related to a variety of environmental issues and interests.The site, located at http://akebono.stanford.edu/yahoo/Environment_and_Nature/, has something for everyone.
For the environmentally health conscious, there are links to organizations concerned with health effects research related to the release of hazardous substances. Most of the links are directed to the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR provides information on its biennial reports to Congress, conferences, congressional testimony, and services such as ToxFAQs, a series of summaries about hazardous substances excerpted from the ATSDR Toxicology Profiles and Public Health Statements, and the Science Corner, a simple support tool for scientists searching the Internet for environmental health information.
For those who religiously recycle glass, paper goods, and other materials and have always wondered how these materials are reincarnated, there is a link to the Recycle Cycle, an electronic exhibit based on a display of the same name by the Northwestern University Recycling Program. The exhibit explores the stages materials go through during the recycling process from disposal to their reemergence as new products.
For those in search of inspiration during Earth Day, there is the John Muir exhibit, (http://ice.ucdavis.edu/John_Muir/Sierra_Club_fact_sheet_on_John_Muir.html). The exhibit documents the history of conservationist John Muir and his profound effect on heightening the public perception of nature. The exhibit includes a biography, images, and tributes.
For those who want to sound off on environmental issues, there is an on-line soapbox onto which they may climb called Envirochat. Envirochat allows all users logged into the site to talk about any issue pertaining to the environment.
In remembrance of Earth Days past, users might ponder the "40 Tips to Go Green" pamphlet distributed by the Jalan Hijau ("Go Green" in Malay) Environmental Action Group during Earth Day 1992 in Singapore. Although the pamphlet is three years old, the information is still relevant and serves as a pleasant reminder to keep up "green" practices.
Finally, for those really thinking globally, there is a link to the Enviroweb--a project of the Envirolink Network, the largest on-line environmental information service on the planet, which reaches over 400,000 people in 93 countries.
Last Update: September 5, 1997