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USGS Activities Related to Human Health Full listing of USGS activities related to human health from the GeoHealth Newsletter June 2007
December 2006
June 2006
Human Exposure to Mercury in UkraineAn integrated environmental/human health study is underway in Gorlovka, Ukraine, where elevated levels of mercury occur primarily due to past mercury mining and processing activities. Mine waste from mercury production, and current domestic and industrial use of coal from local sources, contribute to elevated levels of mercury in the environment. The study, Feasibility of Assessing Health Risks from Long-term Mercury Exposure in Gorlovka, Ukraine, funded by the U.S. Civilian Research and Development Foundation, has been incorporated into U.S. Geological Survey (USGS) project work on Health Effects of Energy Resources. The goals of the work in Gorlovka are to define levels of human exposure to mercury, assess possible health effects to exposed individuals, and determine the feasibility of larger scale epidemiologic studies. The project involves U.S. participants from the USGS, the Armed Forces Institute of Pathology, and Sciences International, Inc., as well as Ukrainian scientists from the Academy of Medical Sciences of Ukraine Institute for Occupational Health, and Donetsk National Technical University. During a field visit to Gorlovka in August 2005, samples of hair, nails, blood, and urine were taken from a group of 30 workers at a mercury recycling facility on the site of the defunct Nikitovka mercury extraction plant. The scientists also collected environmental samples to assess mercury levels and potential exposure near the mercury mines and over a larger portion of Gorlovka. Further sampling will focus on Gorlovka residents lacking occupational mercury exposure, and residents of a nearby control municipality. This research has the potential to be an important human health case study of mercury exposure.
Navajo Students Assist in Coal Combustion and Air Quality StudyUSGS scientists are collaborating with the Navajo Nation Division of Health on respiratory health issues related to coal combustion products in ambient air and indoor air quality where coal is burned industrially and for home heating. USGS researchers will be assisted by Navajo students this summer (2006) to collect air samples. The samples will be analyzed and compared with samples collected this winter. USGS Scientist Named Director of the International Medical Geology Association's North American Regional DivisionThe USGS's Joe Bunnell has accepted the nomination as Director of the newly established North American Regional Division
of the International Medical Geology Association (IMGA). The IMGA, formally
inaugurated in January 2006, now has established Regional Divisions throughout the world. The Association grew out of
interest in Medical Geology that continues to expand worldwide at an increasingly rapid rate. The IMGA should enable the
community to better respond to numerous opportunities, to rapidly pass information to those interested in Medical Geology
issues, and to make critical decisions that will benefit this emerging scientific discipline. October-December 2004Coccidioidomycosis: Mitigating the Riskby Mark W. Bultman, Frederick S. Fisher, and Mark E. Gettings; Western Mineral Resources, Tuscan Arizona Introduction
In the upper 20 cm of some desert soils in the southwestern U.S., northern Mexico, and parts of Central and South America lives a dimorphic fungus that is the only eukaryote regulated under the U.S. Anti-terrorism and Effective Death Penalty Act. This fungus is Coccidioides and it is the etiological agent of coccidioidomycosis, also called valley fever. As it grows in the soil in its saprophytic phase, it is characterized by branching segmented hyphae that form a network of mycelium. As the fungus matures arthroconidia (spores), 2 to 5 microns in size, are formed as barrel shaped segments of the hypha (figure 1). The arthroconidia can be easily separated from the hypha by soil disturbance (natural or anthropogenic) and consequently dispersed by the wind. If an appropriate host inhales airborne arthroconidia, primary infection may occur and the parasitic phase of the Coccidioides lifecycle is initiated. Appropriate hosts include humans and other vertebrates. The life cycle of Coccidioides concludes with the death and subsequent decay of the infected host, returning the fungus to its saprophytic form in the soil.
Character of coccidioidomycosis in humansCoccidioidomycosis begins with the inhaled arthroconidia growing into spherules in the host’s lung tissue. The spherules mature, rupture, and release up to thousands of endospores. Each endospore can grow into a mature spherule and the infection propagates by this method. About 100,000 people are infected annually in the United States (Valley Fever Center for Excellence, 2002). Sixty to seventy percent of infected individuals will be asymptomatic and will develop long-lasting immunity. The remainder display symptoms that range from an influenza-like illness to over-whelming pneumonia starting 7-28 days after exposure. Most recover completely and develop long-lasting immunity. In a small number of cases (<1 percent), a progressive pneumonia can persist for months to years (Ampel, 2000). In about 0.5 percent of cases, the disease may disseminate into the skin, bones, soft tissue, or meninges (figure 2) and may require lifelong anti-fungal therapy. It can also disfigure, disable, or kill the infected individual. The risk of developing active pulmonary coccidioidomycosis varies by age, gender, and, possibly, the level of exposure to the fungus. Figure 3 displays the incidence rate for coccidioidomycosis by age in Arizona from 1990 through 1995. Figure 3 clearly shows that elderly individuals are more susceptible to acquiring active coccidioidomycosis (CDC, 1996). Males tend to get coccidioidomycosis at a higher rate than females and diabetics tend to get a more serious form of pulmonary coccidioidomycosis than non-diabetics (Ampel, 2000). Also, in cases where there is a large exposure to inhaled arthroconidia, such as workers at an archeological dig, almost everyone exposed comes down with active pulmonary coccidioidomycosis (CDC, 2001). The risk of developing disseminated coccidioidomycosis varies by ethnicity and other factors. Blacks, Filipinos, Native Americans, males, and pregnant women in the second and third trimester are at an elevated risk for disseminated infection (Ampel, 2000). Those at the greatest risk from coccidioidomycosis (pulmonary and disseminated) are individuals with an underlying immunosuppressive condition (HIV/AIDS, lupus, organ transplants, chemotherapy, etc). In fact, disseminated coccidioidomycosis is commonly fatal in HIV patients. HIV infected patients with the non-meningitis form of disseminated coccidioidomycosis had a fatality rate of 68 percent and a median survival of 54 days (Aberg, 2003). Those with coccidioidal meningitis had a 33% fatality rate and a median survival of 6 months (Aberg, 2003).
Coccidioidomycosis is a dangerous and expensive disease. Pappagianis (1980) estimated that the overall annual cost to the nation was one million person-days of labor. A review by the United States Centers for Disease Control and Prevention in Atlanta, Georgia (Goodman, ed., 1994) of the medical records in Kern County, California showed that coccidioidomycosis accounted for approximately $66 million in direct costs of hospitalization and outpatient care during the period 1991-1993. Based on demographic trends in the United States an increasing number of previously un-exposed high-risk individuals (mostly elderly) are moving into endemic areas. In addition, recent changes in climate may favor infection. These factors have combined to create an increasing number of cases of coccidioidomycosis in the U.S. In 2001, the Arizona Department of Health Services reported an incidence of 43 cases per 100,000 population, a 186 percent increase in the incidence rate since 1998 (CDC, 2003). Geology and ecology of Coccidioides sp.The coccidioidomycosis endemic area is shown in figure 4. This area represents the geographical extent of environmental conditions favorable for Coccidioides to complete its life cycle in the soil. Coccidioidomycosis was entirely attributed to Coccidioides immitis until recently. Work by Fisher and others (2002) has provided evidence of two species of Coccidioides; Coccidioides immitis and Coccidioides posadasii. Coccidioides immitis is found in the central valley of California, southern California, and Mexico. Coccidioides posadasii is found in the parts of the endemic area outside the central valley of California (Fisher and others, 2002).
Ongoing project work at the USGS Mineral Resource Program’s Southwest Field Office in Tucson, Arizona is aimed at 1) defining the geological/ecological habitat of Coccidioides sp.; 2) modeling that habitat with spatial and temporal models in order to map soils favorable for hosting Coccidioides sp. and delineating conditions where arthroconidia may be released into the atmosphere; and 3) with USGS Earth Surface Dynamics Program, to monitor and model dust emissions. The goal is to use this information to help mitigate coccidioidomycosis by predicting possible epidemics, sighting public facilities in areas where the fungus is not likely to be found, allowing biological and chemical control methods to be effectively utilized, and by allowing dust abatement methods to be used with greater effectiveness. Laboratory and site-specific field studies have shown that many physical, chemical, climatic, and biological factors influence the growth of Coccidioides in the soil and the consequent development and deployment of arthroconidia. With some exceptions endemic areas are generally arid to semiarid with low to moderate rainfall, mild winters, and long hot seasons. Mean annual soil temperatures range from 150°C to over 220°C. The presence of soils with textures that provide adequate pore space in the upper (20 cm) parts of the soil profile, for moisture, oxygen, and growing room is very important. Small amounts of clay foster water holding capacity, but large amounts of clay may be detrimental for Coccidioides growth. The presence of some organic material is needed for carbon and nitrogen but in most known occurrences it is generally sparse, less than 2%. Large amounts of organic compounds may be detrimental because they would foster the growth of bacteria and other fungal species that would compete with Coccidioides. Many Coccidioides growth sites have soils with elevated salinity, which may act an inhibitor of microbial competitors (Egeberg and others, 1964). Detection of Coccidioides in the environment is difficult. Traditionally mice are inoculated with isolates from suspect soil. After a pre-determined time period the mice are sacrificed and their organs examined for evidence of infection as seen by the formation of the unique spherule form of Coccidioides. Recently, laboratories have turned to DNA analysis in an attempt to identify the cultured fungus. While there have been some successes using DNA, there is no standardized procedure and results so far are unreliable. Scientist collaborating with the USGS at the University of Arizona and the University of California Davis are working on the development and improvement of these new techniques. Presently, testing soil for the presence of Coccidioides is time consuming and difficult, thus there are few locations where it has been identified in the soil. Coccidioides sp. habitat modelingHabitat modeling of the saprophytic phase of Coccidioides is difficult, because of the limited number of places where it is known to exist in soil. This prevents the establishment of statistical relationships between growth sites and their physical, chemical, and biological habitat parameters. Therefore habitat modeling is accomplished using analysis of the physical properties of known Coccidioides sites within a spatial fuzzy system. A spatial fuzzy system is a system of spatial variables where some or all of the spatial variables are described with fuzzy sets. The fuzzy system is capable of translating structured knowledge into a flexible numerical framework and processing it with a series of if-then rules. Fuzzy systems can describe non-linear numerical processes with linguistic common sense terms and can handle differing precision and accuracy in the data. They produce models that can be repeated and updated easily.
A fuzzy system analysis was applied in Organ Pipe Cactus National Monument, Arizona. The resulting product is a map (Figure 5) depicting the favorableness of areas for hosting Coccidioides in soils based on a scale of 0 to 1, which we define as its fuzzy habitat suitability index. An important property of this kind of analysis is that “what if” scenarios can be used to predict changes in habitat with changing climate. Complex systems modeling of the life cycle of CoccidioidesLike all environmental systems, the life cycle of Coccidioides is determined by a complex set of interactions between the organism and its surroundings. One concept that we are now testing is the possibility that saprophytic Coccidioides can reestablish itself in soil after arthroconidia have been blown to a new location by an extreme wind event. Fisher and others (2001) have shown that there is spatial genetic differentiation in Coccidiodes and geographically separate genetic clades are recognized in central California, southern California, Arizona, Mexico, Texas, and South America. This genetic differentiation argues against the ability of Coccidioides arthroconidia to reestablish themselves in soils, at least over long distances. But, spread of the fungus by wind may still be an important local process. In an attempt to model the spread and survival of the fungus Coccidioides in soil via wind-borne arthroconida transport, a complex systems model has been developed using public domain agent-based modeling software. The hypothetical model posits that for a successful new site to become established, four factors must be simultaneously satisfied. 1) There must be transport of arthroconidia from a source site to sites with favorable soil (physical, chemical, and biological properties). 2) There must be sufficient moisture for fungal growth. 3) Soil temperatures at the surface and at depth must be favorable for growth. Finally, 4) the temperature and moisture must remain in favorable ranges for a long enough time interval for the fungus to grow down to depths at which arthroconidia will survive subsequent heat, aridity, and ultraviolet radiation of the hot, dry season typical of the Southwest U.S. climate. Numerous model runs have shown that the probability of new sites depends on the four factors in a Bayesian way. These results indicate that the complexity introduced in the model from site favorableness, temperature, moisture, and duration of favorable temperature and moisture conditions is adequate to explain distributions of real sites described in the literature and that wind transport at a local scale may be possible. We are now working on integrating more physical habitat factors as well as soil favorableness information into the complex systems model. References
Formation of new USGS Human Health Coordination CommitteeCharles G. Groat (signed) Chip Groat Director, USGS I am pleased to announce that Herb Buxton has agreed to chair a USGS Human Health Coordination Committee. This committee, comprising program coordinators who currently support Human Health research, will work to increase coordination with human health agencies and coordination among USGS human health related activities. Some of the committee’s first tasks will be to develop long-term strategies to identify focused research areas for the USGS, to strengthen our partnerships with human health agencies, and to identify opportunities for additional funding and growth. As chair of the Human Health Coordination Committee, Herb’s first task will be to work with the Associate Directors to assemble the group. He will also serve as the USGS point of contact for health agencies and facilitate interdisciplinary response to their needs. Currently, Herb manages the Toxic Substances Hydrology Program and he will continue in that role concurrently. Human health issues are a high priority for the American people, and, as a Federal agency, the USGS can provide critical science information in this area. However, many of our capabilities are underutilized, particularly in the areas of wildlife health-human health interactions and the use of our environmental databases (water quality, rock and soil geochemistry, land cover, etc). To maximize our impact, we must partner with the health sciences and medical fields to understand their information needs and to educate them about the value USGS can add. As the Toxics Program Coordinator, Herb has worked closely with environmental and human health agencies on topics such as mercury cycling in aquatic ecosystems, contamination from hardrock mining, MTBE, pesticides and their degradation products, and pharmaceutically and hormonally active contaminants. He received his B.S. in Geology from Rensselaer Polytechnic Institute, and his M.S. in Geology from the State University of New York. After working as a research associate at the University of South Carolina’s Hydrogeology Program, he has had a 25-year career with the USGS as a scientist and manager. Please join me in welcoming Herb to this new leadership role. July-September 2003Pharmaceuticals, Hormones, Personal-Care Products, and other Organic Wastewater Contaminents in Water Resources: Recent Research Activities of the U.S. Geological Survey's Toxic Substances Hydrology ProgramBy Michael J. Focazio, Dana W. Kolpin, and Herb Buxton Recent decades have brought increasing concerns for potential contamination of water resources that could inadvertently result during production, use, and disposal of the numerous chemicals offering improvements in industry, agriculture, medical treatment, and even common household products. Increasing knowledge of the environmental occurrence or toxicological behavior of these contaminants from various studies in Europe, United States, and elsewhere has resulted in increased concern for potential adverse environmental and human health effects (Daughton and Ternes, 1999). Ecologists and public health experts often have incomplete understandings of the toxicological significance of many of these contaminants, particularly long-term, low-level exposure and when they occur in mixtures with other contaminants (Daughton and Ternes, 1999; Kümmerer, 2001). In addition, these ‘emerging contaminants’ are not typically monitored or assessed in ambient water resources. The need to understand the processes controlling the transport and fate of these contaminants in the environment, and the lack of knowledge of the significance of long-term exposures have increased the need to study environmental occurrence down to trace (nanogram per liter) levels. Furthermore, the possibility that mixtures of environmental contaminants may interact synergistically or antagonistically has increased the need to characterize the types of mixtures that are found in our waters. The U.S. Geological Survey’s Toxic Substances Hydrology Program (Toxics Program) is developing information and tools on emerging water-quality issues that will be used to design and improve water-quality monitoring and assessment programs of the USGS and others, and for proactive decision-making by industry, regulators, the research community, and the public (http://toxics.usgs.gov/regional/emc/). This research on emerging water-quality issues includes a combination of laboratory work to develop new analytical capabilities as well as field work on the occurrence, fate, and effects of these contaminants. LABORATORY WORKAnalytical Method Research and DevelopmentSince 1998, the Toxics Program has been developing analytical capabilities to measure pharmaceuticals, personal care products, hormones, and other naturally occurring and synthetic organic wastewater compounds (collectively referred to as OWCs) in a variety of environmental matrices (water, sediment, tissue). Without reliable and accurate analytical methods the corresponding field research would be impossible. Currently, more than 140 OWCs can be measured by the U.S. Geological Survey using a variety of liquid and gas chromatographic techniques (e.g. Brown et al., 1999; Barber, et al., 2000; Meyer et al., 2000, Lindsey et al., 2001, Zaugg et al., 2002). Analytical methods are being developed and improved for whole water, filtered water, and bed sediment samples. These methods are capable of detecting OWCs at sub part-perbillion levels in a wide range of natural and anthropogenically impacted waters of variable chemistry and quality. To date, these analytical methods have provided the necessary tools to support field investigations on the occurrence of OWCs in the environment and have begun to support new research projects focused on fate, transport, and effects.
FIELD WORKNational Reconnaissance SurveysTo date, over 500 environmental samples have been collected for the Toxics Program and analyzed for OWCs, representing a broad range of climatic and hydrogeologic conditions. Initial and continuing research has focused on broad reconnaissance surveys of streams, aquifers, and sources of drinking water to determine if these emerging contaminants are entering the Nation’s water resources and if so, at what concentrations and combinations. The surveys are not representative of all water resources in the United States, but do provide the first information on the occurrence of a large range of OWCs in the Nation’s water resources. This work helps researchers develop hypotheses on the sources, fate and transport of OWCs in the environment. The first reconnaissance survey completed consisted of a network of 139 streams across 30 states sampled during 1999 and 2000 (Barnes et al., 2002; Buxton and Kolpin, 2002; Kolpin et al., 2002a; Kolpin et al., 2002b). By design, most streams sampled were known or suspected to be susceptible to sources of human, animal or industrial wastewater (Fig. 1). Results showed that a broad range of chemicals found commonly occurs in mixtures at low concentrations downstream from areas of intense urbanization and animal production. One or more of the 95 chemicals analyzed were found in generally low concentrations in 80 percent of the streams sampled. Half of the streams contained 7 or more of these chemicals, and about one-third of the streams contained 10 or more of these chemicals. Some of the most frequently detected compounds (Fig. 2) included cholesterol (naturally occurring plant and animal steroid), DEET (an insect repellent), caffeine (nonprescription drug), triclosan (antimicrobial disinfectant), and tri (2-chloroethyl) phosphate (fire retardant). Two additional reconnaissance surveys have also been conducted. In 2000, a network of 47 ground-water sites downgradient from, or near, landfills, unsewered suspected to be susceptible to contamination (e.g. residential developments, animal feedlots, etc.) across 18 states was sampled and measured for OWCs (Barnes et al., 2003). In 2001, a network of 76 drinking-water sources (51 surface-water sources and 25 ground-water sources) across 25 states and Puerto Rico was sampled and measured for OWCs (Focazio et al., 2003). All samples for this survey were collected prior to any water treatment practices (e.g. river intakes and raw-water sampling ports). This survey of drinking-water sources was conducted in collaboration with the U.S. Environmental Protection Agency and with assistance from the American Water Resources Association. The results of these two additional reconnaissance surveys are currently being examined and interpreted.
Sources, Fate, and TransportSubsequent and planned research is focused on potential sources of OWCs (e.g. animal feeding operations, fish hatcheries, wastewater treatment plants, etc.) and their fate and transport through the hydrologic system (Campagnolo et al., 2002; Cordy et al., 2002; Patterson et al., 2001; Thurman et al., 2002). Current research includes the collection of both stream water and bed sediment samples to provide a more complete understanding of the occurrence of OWCs and their partitioning in the environment. CONCLUSIONResearch conducted by the USGS’ Toxic Substances Hydrology Program addresses emerging water-quality issues associated with environmental occurrence of pharmaceuticals, hormones, personal care products, and other naturally occurring and synthetic organic wastewater compounds. This research provides new insights on the extent to which chemicals used every day in households, industry, and agriculture are entering and being transported in our water resources. These studies are among the first to address these issues and therefore provide unique data and information for other scientists as well as decision makers in the public and environmental health communities. For more information go to http://toxics.usgs.gov. REFERENCES
Mendenhall Postdoc Program Supports GeoHealth ScienceBy Christina Kellogg Since its inception in 2001, the Mendenhall postdoctoral program has been an avenue for bringing young scientists with new talents and skills into the Geologic Discipline of the USGS. Named in honor of Walter Mendenhall, the fifth Director of the USGS, this program is now moving into its fourth year. Three of the first year Mendenhall Fellows, Thomas L. Ziegler (Denver), Christina A. Kellogg (St. Petersburg) and Joseph E. Bunnell (Reston), gave talks during the recent USGS Conference ‘Natural Science and Public Health—Prescription for a Better Environment.’ The meeting, which focused on the intersection of environmental research and human health, an important venue to highlight the significance of their research. While all three work in the Geologic Discipline, not one is a geologist! Thomas is a toxicologist by training, Chris is a molecular microbiologist, and Joe is a public health biologist. They all play a significant role in linking geoscience with other disciplines. Joe presented his research first, titled ‘Environmental Predictors for Tick-borne Disease Risk in the Middle Atlantic Region, USA.’ Lyme disease, the most common vector-borne disease in the U.S., and ehrlichiosis, an emerging deadly disease, are both bacterial infections that are spread by ticks. In an effort to better quantify the risk factors associated with certain areas, a spatial statistical model incorporating factors such as elevation, soil type and features (texture, waterincluded holding capacity), land cover, and proximity to forests or water bodies, was used to predict areas most supportive to tick populations. The predictions from this model can help target more effective intervention actions and hopefully reduce the number of cases of tick-borne disease. Chris discussed the long-distance transport of microbes in dust from the Sahara/Sahel region ofAfrican in her presentation titled “Out of Africa: Characterization of Microbial Communities Associated with Desert Dust and Their Implications for Human and Ecosystem Health.’ Each year, millions of tons of desert soil dust blow off the west African coast and ride the trade winds across the Atlantic Ocean, routinely impacting the Caribbean and southeastern United States. This dust has been shown to carry living microorganisms, including a wide variety of bacteria and fungi, some of which are capable of causing disease in plants, animals, and humans with weakened immune systems. It is important to characterize and quantify these airborne microbes to assess what effects they may have on downwind ecosystems. Asbestos is a general term for a group of fibrous silicate minerals used in many construction materials due to their fire-resistant nature. Asbestos can be divided into two mineral groups, serpentine and amphibole, based on the crystalline structure. Serpentines have a sheet or layered structure, while amphiboles have a chain-like structure. In spite of its many applications, usage has declined due to links between asbestos and diseases including lung cancer. In his talk titled, “Mineralogical, Geochemical, and Toxicological Variations of Asbestos Toxicological Standards and Amphibole Samples from Libby, MT,” Thomas described how asbestos standards are not as uniform as one would expect. In fact, the chemical analyses of a series of asbestos standards (amosites, anthophyllites, chrysotiles, crocidolites and tremolites) indicated that elemental content varied within standards of the same mineral. Furthermore, each asbestos mineral, even those labeled as the same mineral, has its own profile of accessory minerals which may play a role in the wide range of toxicity seen in the cell line toxicity data presented and possibly explain some of the conflicting reports for asbestos toxicity found in the literature. In addition, toxicity data was presented for the Libby, MT amphibole that was revealed to be significantly more toxic than the asbestos standards in comparison. In addition to the 20 minute talks given during the conference, both of the ‘out-of-towners’ gave hour-long lectures about their Mendenhall research in the USGS Visitors Center; Thomas spoke the Monday before the conference, and Chris followed on the Friday after. For more information on the Mendenhall program, including profiles of the Fellows and their research projects, please visit the web site: http://geology.usgs.gov/postdoc/ or contact Rama Kotra (rkotra@usgs.gov). November 1, 2002Weathered Lignite Deposits and Balkan Endemic Nephropathyby Gerald L. Feder
Balkan endemic nephropathy (BEN) is a fatal kidney disease that is known to occur only in geographically discrete areas of the Balkan Peninsula in Eastern Europe. The disease was first described in 1956, but may have existed for many centuries. The disease seems to occur only in rural villages located on alluvial valleys of tributaries of the lower Danube River (Figure 1). Although the disease is apparently geographically restricted to a relatively small area, BEN is a significant public health problem. At least 25,000 people are believed to be suffering from BEN, and over 100,000 people may be at risk. Researchers have been trying to determine the cause(s) of BEN for almost half a century, but there is still no consensus among the scientific community as to its etiology. Some local villagers feel that mysterious cosmic powers are responsible, and wear protective amulets or pendants and perform ritual prayers to ward off the disease. Western medicine generally opines that certain environmental exposures, genetic predisposition, and/or an infectious agent is the more likely cause.
A common geologic feature of endemic villages is the proximity to distinctive low rank Pliocene lignite deposits and lignitic shales that were deposited about 5.3 to about 1.6 million years ago. Researchers at USGS hypothesize that weathering of the lignites and associated shales yield toxic soluble organic compounds, and that these toxins are transported by the local ground water flow system to the shallow water wells used by the villagers. Figure 2 shows an alluvial valley typifying the geologic and hydrologic setting of endemic home sites. Laboratory analysis at USGS of water samples from endemic and nonendemic villages indicate the presence of potentially carcinogenic and nephrotoxic organic compounds (Figure 3). These include napthylamines, aniline, aminophenols, alkyl phenols, biphenyls, and heterocyclic (N-, O-, and S containing) compounds in much higher concentrations in the endemic villages than nearby non-endemic villages.
The disease has several features that characterize it as a distinct clinical entity. Unlike the case with many other kidney disorders, BEN patients do not, as a rule, have high blood pressure. And a significant number of BEN patients also have an otherwise unusual type of upper urinary tract cancer. Only stable, rural populations of people seem to get BEN. The stability implies a long “incubation period” for the disease, consistent with ingesting low levels of toxic compounds from rural water wells over decades. There are no known cases of BEN among people living in cities and drinking water from a municipal supply. Making the diagnosis of BEN is made challenging by the lack of any specific sign, or marker of the disease. Only when the particular constellation of symptoms and the patient’s history are in keeping with BEN is the diagnosis made. Thus there could be many more people suffering from BEN than is currently recognized. Autopsies are not routinely performed in this region, and only a post-mortem examination can confirm BEN as the cause of death. The kidneys are shrunken to about 30% their normal size. BEN patients in some areas now undergo new sophisticated ultrasound procedures to help confirm the presence of shrunken kidneys, and the proper diagnosis of BEN. The clinical and pathological characterization of the disease has been followed by a sustained search for its causative factors, involving international teams and multidisciplinary approaches. At present, fatalities from BEN still occur in the same regions, and the etiology of the disease is still not known. The main fruits of BEN research, up to the present, have come mostly from excluding some fruitless hypotheses, and to redirect future investigations and hypotheses. A currently accepted concept is that BEN is an environmentally induced disease, and some of the most consistently incriminated agents are toxic organic compounds present in the drinking water from shallow wells in the endemic areas. Researchers at USGS hypothesize that these compounds may be leached by groundwater flowing through the nearby low rank Pliocene coal (lignite) deposits, and transported into shallow household wells dug into the alluvium. Until the past decade, most people in the endemic villages used water from these shallow hand dug household wells, for drinking and other purposes. Over the past decade an increasing number of endemic villages are getting public surface water supplies, piped in to household faucets from regional surface water reservoirs. These reservoirs are quite distant from the endemic villages, and are filled by surface water runoff that is independent of the ground water system supplying the wells in the endemic villages. Moreover, the treatment process for this water renders formerly toxic compounds harmless. It will be very useful to study the people in these villages to see if the people raised from childhood using piped-in water no longer develop BEN.
One of the characteristics of BEN is that people generally don't develop the disease unless they have lived in an endemic village for the first 15-20 years of their life. They then generally won't develop the disease until they are about 40 to 50 years old. Once they develop the disease, it is fatal, unless they go on dialysis, or get a kidney transplant. Due to the high cost of kidney transplants, and the low economic status of most villagers in the endemic areas, most patients must spend the rest of their lives on dialysis. Many BEN cases are reported where a person moves out of an endemic village at about 20 years of age, and they are later diagnosed with the disease when they are about 40 or 50 years old. Though the correlation between endemic villages and the proximity to Pliocene lignite deposits seems to be established, many researchers believe BEN may be a multicausal disease. For example, genetic factors may predispose a person to develop BEN if they are exposed to certain toxic organic compounds early in their lives, or even prenatally. Similarly, it is possible that childhood exposure to fungal toxins known to damage the kidneys or infection with bacteria that attack the kidneys sets one up for developing BEN. Subsequent long term exposure to low levels of toxic organic lignite-derived compounds may then seal the person’s fate, leaving unharmed someone with no such history. While BEN is not known to occur in the United States, it is curious that this country’s lignite deposits occur in states with the highest rates of cancers of the renal pelvis (RPC). Louisiana has the sixth highest Renal Pelvic Cancer (RPC) mortality rate in the United States. Other states with major lignite deposits are Wyoming and the Dakotas; Wyoming ranks first in the USA for RPC, and North and South Dakota rank third and fourth, respectively. All of these states have large rural populations that obtain drinking water from wells. A team of scientists from USGS, the Louisiana Geological Survey, the Centers for Disease Control and Prevention, and the Louisiana State University Medical School have begun investigations designed to see if a BEN-like syndrome exists in this country. It will also be instructive to look closely at countries with large lignite deposits like Greece and Turkey. However, health data from these nations are sometimes unreliable, and are often difficult to obtain. While a clear understanding of the cause(s) of BEN remains elusive, there is good reason to be hopeful that we will soon identify the risk factors, and enable preventative measures that will protect large numbers of people from this illness. This issue represents an example of how geoscience experts and the public health and biomedical community need to communicate, cooperate, and collaborate to untangle the intricacies of complex disease etiologies having an environmental component. That is to say, for all of the misery it brings, BEN does seem to be a valuable mechanism for Epidemioecologists to demonstrate their worth. Jerry Feder, one of the world's foremost BEN investigators and has retired from the USGS, but may still be contacted at glfeder@tu.infi.net or gl9202@aol.com. A fact sheet summarizing BEN may be found at http://pubs.usgs.gov/fs/fs004-01. August 1, 2002The Movement of Soil and Sediment in Earth’s Atmosphere: Microbiology and Ecosystem HealthD.W. Griffin, C.A. Kellogg, V.H. Garrison, C. Holmes, and E.A. Shinn A rain of dirtWhile soils and sediments in Earth’s atmosphere originate from arid regions around the globe, the majority of ‘dust’ originates from two locations, the Sahara and Sahel regions of Africa and the deserts of Asia. Dust storms originating in the arid regions of North Africa occur year round and account for approximately 75% of all soils and sediments lifted into our atmosphere. In the months from June through October dust originating from Africa routinely impacts the Caribbean, Central and North America. In the remaining months the African dust storms typically impact South America, Europe and the Middle East. Dust storms originating in the Asian deserts usually occur from February through April of each year. While the Asian deserts are smaller than the Sahara and the dust season is only three months long, they are a significant source of airborne soils and sediments.
The current estimate on the quantity of soil moving some distance in Earth’s atmosphere each year is approximately 2 billion metric tons and some feel that this may be a significant underestimate (Figure 1. A dust cloud the size of Spain rolling off the Western coast of the Sahara Desert). If you converted that 2 billion ton estimate into Volkswagen Beetles (based on weight), that would be enough Beetles to create a 119 meter tower over the entire 176 km2 surface area of Washington, D.C. From a microbiology perspective there is an additional piece of trivia - the 2 billion ton estimate converts to 2 quadrillion grams. At a conservative estimate of 10,000 bacteria per gram, that’s enough bacteria, if placed end to end, to form a microbial bridge between Earth and Jupiter. Additionally, such dust also transports fungal and viral microbial pathogens. With respect to human and ecosystem health, one has to ask what percentage of the associated microbial population is pathogenic and how many of these disease-causing microbes are capable of surviving long range airborne transport? What risks do these and other potential hazards such as herbicides, pesticides and radioisotopes that have also been identified in dust clouds pose to impacted populations of humans and ecosystems? These are questions with global implications, questions that are being addressed by a surprisingly small number of researchers. The GoodThe movement of soils and exposed sediments in atmospheres is a natural planetary process; Martian dust devils as imaged by NASA’s interstellar exploration efforts are a prime example. Analysis by researchers on ice cores taken in the Arctic and Antarctic have demonstrated periods of both heavy and light global dust transport as Earth has evolved to our current point in time. Terrestrial and aquatic plant life have evolved to take advantage of the nutrient-rich particles (iron, phosphate and organic detritus) in clouds of dust that fall out of the atmosphere. Research has shown that plant life in the upper canopy of the South American rain forest derive their nutrients from African dust. Rain forests located on the Northern Hawaiian Island chain are believed to obtain a significant fraction of their nutrient budget from Asian desert dust. Researchers are currently investigating the influence of nutrient-laden dust on growth of phototrophic microorganisms in oligotrophic regions of our oceans. The deposition of clay-laden African dust on Caribbean Islands through time enabled ‘Pre-Columbian’ Indians to produce pottery from an otherwise clay-limited soil. Clearly the global movement of dust has benefited both ecosystems and humanity. The Bad and the UglyOne of the first links to be made between long range transport of desert dust and ecosystem health was the isolation and identification of a terrestrial fungus (Aspergillus sydowii) as the causative agent of the Caribbean-wide seafan disease agent from atmospheric samples collected in the United States Virgin Islands. There is a replete history of research that has implicated long-range dispersion fungal pathogens of plants and crops over vast expanses of terrestrial and marine environments. In the 1970’s sugarcane rust caused by Puccinia melanocephala was surmised to have spread from Africa to the Caribbean and then to North America via airborne transport. Similarly, the coffee rust agent Hemileia vastatrix was suspected of being delivered from Africa to the Caribbean via the atmosphere. Outbreaks of foot-and-mouth disease have been reported in Korea following large dust events originating in China’s deserts. Research on the source of the pseudorabies virus (cause of Aujeszky’s disease in pigs) after outbreaks occurred in Denmark in December of 1988 concluded that the infections were probably due to atmospheric transport of the viral pathogen from Germany. Recent research conducted at the University of South Florida’s Department of Marine Sciences has implicated African dust deposition and outbreaks of harmful algal blooms (red tide) along Florida’s coastline. The National Institute of Allergy and Infectious Diseases identifies airborne dust as the primary source of allergic stress worldwide. Areas such as the Aral Sea (The Aral Sea, along with other inland bodies of water such as Lake Chad in Africa and Lake Owens in California, are significant sources of dust due to the fine nature of exposed sediments produced by drought and/or source water diversion, i.e. falling water tables) and the Caribbean, where desert dust activity is common, have some of the highest recorded incidence rates of human asthma on the planet. Barbados experienced a 17-fold increase in the incidence rate of asthma from 1973 to 1996. This observed increase in incidence coincided with the increased dust flux from the Sahara and Sahel to the Caribbean. A number of diseases such as ‘Al Eskan Disease’ a.k.a. ‘Desert Storm Pneumonitis,’ and ‘Desert Lung Syndrome’ have been attributed to exposure to atmospherically suspended desert dusts. Exposure to airborne dust containing bacterial endotoxin and mycotoxins produced by fungi is known to cause disease and death. Large outbreaks of meningococcal meningitis (caused by the bacterium Neisseria meningitidis) resulting in both illnesses and death are routinely reported in West African countries following dust events. In the Americas, small outbreaks of coccidioidomycosis (caused by the fungal pathogen Coccidioides immitis) following dust events are common. Widespread use of pesticides and herbicides in farming and the subsequent airborne transport of toxin-laden soils pose a risk to human health. People living in the vicinity of the Aral Sea have suffered from illnesses due to the organosphosphate pesticide phosalone exposure. Analysis of human breast milk collected from women in southern Kazakhstan found levels of beta-hexachlorocyclohexane (an organochlorine pesticide residue) that were some of the highest concentrations published in scientific literature. Additional research in the region found high concentrations of this pesticide residue and dichloro-diphenyltrichloroethane (DDT) compounds in children’s blood. The Arctic is impacted by pesticide and herbicide-laden clouds of desert dust originating from both Asia and Africa where they are used to maximize crop yield and, ironically, to counter other threats to public health. Pesticides in Arctic animals and Inuit Indian breast milk have been documented. A recent concern in long range dust movement and those populations persistently exposed to these dust particulates is recent evidence that isotopes such as beryllium-7 may accumulate on dust particles as they move through the atmosphere. While the potential risk to human populations is not presently clear, this emerging issue in global dust movement is a research area of much concern.
Atmospheric Soils and Sediments and the USGSOur research group at the USGS, Center for Coastal and Regional Marine Studies has documented increases in the numbers of airborne microorganisms in the US Virgin Islands, when the region is being impacted by African dust. The US Virgin Island data has shown that during dust events the number of organisms that can be cultured or observed using nucleic acid stains typically ranges from 2 to 10 times what is seen during normal/clear conditions (similar wind velocity and directions as seen during a dust event). Due to collaborative efforts, we are also currently conducting research in Mali, Africa and on the Mediterranean coastline of Turkey. These projects have been undertaken in order to understand the significance of what we are observing in the Caribbean versus dust cloud point of origin (Mali) and regions being impacted that are in closer proximity to the source (Turkey). We are also collaborating with NASA and the US Air Force to address the presence of microorganisms moving in Earth’s atmosphere at high altitudes. Data obtained from Mali samples (Figure 2) indicates that approximately 90% of the organisms that start the airborne trip in Africa die before they reach our Caribbean sample site. While this may seem significant one should keep in mind that a single gram of soil contains on average of approximately a million bacteria cells and with a die off rate of 90%, that still leaves 100,000 viable bacteria -- and that’s just in a single gram! Of those US Virgin Island isolates we have identified using DNA sequencing of the ribosomal gene, ~20% are species known to cause disease in a broad range of plant life and ~10% are known opportunistic human pathogens. New efforts undertaken this summer include DNA fingerprinting of the entire microbial community captured in our air samples (in order to identify uncultivable populations) and analysis of the previously observed viral community which are known to be present in our samples (microscopy and molecular techniques to define the virus community). Samples for use in screening dust events for pesticides and herbicides are currently being collected in the US Virgin Islands and radioisotope work on dust samples has shown extremely high levels of beryllium-7 and lead-210. This is but a short synopsis of where what our research has shown us and where it is leading us. Our focus is currently human and ecosystem health (particularly coral reef health) as it relates to the long-range transport of African dust. Future efforts should expand into the Asian dust arena and collaborative efforts with USGS scientists currently involved in understanding dust issues in the American Midwest. For more specific information on our research data and the world of dust and health please see the following articles or website. More Information
AcknowledgementsOur research has been supported by funding from NASA’s Earth Science and Public Health Program (grant # 7242-60050). Hormone Disruption Research Act of 2002HR 4709 was introduced in the House on May 9,2002, to amend the Public Health Services Act to authorize the Director of the National Institute of Environmental Health Sciences (NIEHS) to conduct and coordinate a research program on hormone disruption. The bill was referred to the Subcommittee on Research on May 15. This bill mentions the USGS' considerable experience assessing the occurrence of chemicals in the environment, ecological health, and the hazards to wildlife health and associated human health posed by chemicals in the environment, as a result of monitoring by the USGS of the Nation's water resources and wildlife disease, and research by the USGS on the effects of chemicals on wildlife. The bill calls for $500,000,000 for NIEHS for the 5-fiscal-year period beginning with fiscal year 2003. The Director of NIEHS may transfer funds to other Federal agencies to carry out the Director's responsibilities outlined in the bill. Some of the language in HR 4709 which mentions USGS includes the following:
May 2, 2002
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