The interactions between earth materials and processes and human health are pervasive and complex. In some instances, the association between earth materials and disease is clear—certain fibrous (asbestos) minerals and mesothelioma, radon gas and lung cancer, dissolved arsenic and a range of cancers, earthquakes and physical trauma, fluoride and dental health—but these instances are overshadowed by the many cases where individual earth components, or more commonly mixtures of earth materials, are suspected to have deleterious or beneficial health impacts. Unraveling these more subtle associations will require substantial and creative collaboration between earth and health scientists.
The surge of interest and research activity investigating relationships between public health and earth’s environment that commenced in the 1960s has not been sustained. Today, few researchers span the interdisciplinary divide between the earth and public health sciences, and “stove-pipe” funding from agencies provides little incentive for researchers to reach across that divide. The limited extent of interdisciplinary cooperation has restricted the ability of scientists and public health workers to solve a range of complex environmental health problems, with the result that the considerable potential for increased knowledge at the interface of earth science and public health has been only partially realized and opportunities for improved population health have been threatened.
In response to this situation, the National Science Foundation, U.S. Geological Survey, and National Aeronautics and Space Administration requested that the National Research Council undertake a study to ex-
plore avenues for interdisciplinary research that would further knowledge at the interface between the earth science and public health disciplines. The study committee was charged to advise on the high-priority research activities that should be undertaken for optimum societal benefit, to describe the most profitable areas for communication and collaboration between the earth science and public health communities, and to respond to specific tasks:
Describe the present state of knowledge in the emerging medical geology field.
Describe the connections between earth science and public health, addressing both positive and negative societal impacts over the full range from large-scale interactions to microscale biogeochemical processes.
Evaluate the need for specific support for medical geology research and identify any basic research needs in bioscience and geoscience required to support medical geology research.
Identify mechanisms for enhanced collaboration between the earth science and medical/public health communities.
Suggest how future efforts should be directed to anticipate and respond to public health needs and threats, particularly as a consequence of environmental change.
The committee addressed this charge by focusing its analysis on human exposure pathways—what we breathe, what we drink, what we eat, and our interactions with earth materials through natural and anthropogenic earth perturbations (e.g., natural disasters, land cover modifications, natural resource use). Specific examples for each exposure pathway are presented to highlight the state of existing knowledge, before listing priority collaborative research activities for each exposure pathway. These research activities are grouped into three broad crosscutting themes: (1) improved understanding of the source, fate, transport, bioavailability, and impact of potentially hazardous or beneficial earth materials; (2) improved risk-based hazard mitigation, based on improved understanding of the public health effects of natural hazards under existing and future climatic regimes; and (3) research to understand the health risks arising from disturbance of terrestrial systems as the basis for prevention of new exposures. The committee received suggestions for broad research initiatives and specific research activities from national and international participants from the earth science, public health, and government funding communities at an open workshop, and these suggestions formed the basis for deliberations to identify the research themes considered by the committee
to have the highest priority. In compiling these recommendations the committee required that the research proposed must involve collaboration between researchers from both the earth science and the public health communities and did not consider the abundant examples of valuable research that could be undertaken primarily within one or other of the disciplines.
Earth Material Exposure Assessments—Understanding Fate and Transport
Assessment of human exposure to hazards in the environment is often the weakest link in most human health risk assessments. The physical, chemical, and biological processes that create, modify, or alter the transport and bioavailability of natural or anthropogenically generated earth materials remain difficult to quantify, and a vastly improved understanding of the spatial and geochemical attributes of potentially deleterious earth materials is a critical requirement for effective and efficient mitigation of the risk posed by such materials. An improved understanding of the source, fate, rate and transport, and bioavailability of potentially hazardous earth materials is an important research priority. Collaborative research should include:
Addressing the range of issues associated with airborne mixtures of pathogens and physical and chemical irritants. The anticipation and prevention of health effects caused by earth-sourced air pollution prior to the onset of illness requires quantitative knowledge of the geospatial context of earth materials and related disease vectors.
Determining the influence of biogeochemical cycling of trace elements in water and soils as it relates to low-dose chronic exposure via toxic elements in foods and ultimately its influence on human health.
Determining the distribution, survival, and transfer of plant and human pathogens through soil with respect to the geological framework.
Improving our understanding of the relationship between disease and both metal speciation and metal-metal interaction.
Identifying and quantifying the health risks posed by “emerging” contaminants, including newly discovered pathogens and pharmaceutical chemicals that are transported by earth processes.
Improved Risk-Based Hazard Mitigation
Natural earth processes—including earthquakes, landslides, tsunamis, and volcanoes—continue to cause numerous deaths and immense suffering worldwide. As climates change, the nature and distribution of
such natural disasters will undoubtedly also change. Improved risk-based hazard mitigation, based on improved understanding of the public health effects of natural hazards under existing and future climatic regimes, is an important research priority. Such collaborative research should include:
Determining processes and techniques to integrate the wealth of information provided by the diverse earth science, engineering, emergency response, and public health disciplines so that more sophisticated scenarios can be developed to ultimately form the basis for improved natural hazard mitigation strategies.
Assessment of Health Risks Resulting from Human Modification of Terrestrial Systems
Human disturbances of natural terrestrial systems—for example, by activities as diverse as underground resource extraction, waste disposal, or landcover and habitat change—are creating new types of health risks. Research to understand and document the health risks arising from disturbance of terrestrial systems is a critical requirement for alleviating existing health threats and preventing new exposures. Such collaborative research should include:
Analysis of the effect of geomorphic and hydrological landsurface alteration on disease ecology, including emergence/resurgence and transmission of disease.
Determining the health effects associated with water quality changes induced by novel technologies and other strategies currently being implemented, or planned, for extending groundwater and surface water supplies to meet increasing demands for water by a growing world population.
Geospatial information—geological maps for earth scientists and epidemiological data for public health professionals—is an essential integrative tool that is fundamental to the activities of both communities. The application of modern complex spatial analytical techniques has the potential to provide a rigorous base for integrated earth science and public health research by facilitating the analysis of spatial relationships between public health effects and natural earth materials and processes. Research activity should be focused on the development of high-resolution, spatially and temporally accurate models for predicting disease distribution that incorporate layers of geological, geographic, and socioeconomic data.
This will require development of improved technologies for high-resolution data generation and display.
Before it will be possible to take advantage of the considerable power of modern spatial analysis techniques, a number of issues associated with data access will need to be addressed. Improved coordination between agencies that collect health data will be required, and health data from the different agencies and offices will need to be merged and made available in formats that are compatible with GIScience analysis. Existing restrictions on obtaining geographically specific health data, while important for maintaining privacy, severely inhibit effective predictive and causal analysis. To address this, it will be necessary for all data collected by federal, state, and county agencies to be geocoded and geographically referenced to the finest scale possible, and artificial barriers to spatial analysis resulting from privacy concerns need to be modified to ensure that the enormous power of modern spatial analysis techniques can be applied to public health issues without affecting privacy.
Although important gains have been made within individual funding agencies toward support for interdisciplinary research, a dearth of collaboration and funding between agencies has restricted significant scientific discovery at the interface of public health and earth science. The committee suggests that, for there to be substantial and systemic advances in interdisciplinary interaction, a formal multiagency collaboration support system needs to replace the existing ad hoc nature of collaborations and funding support. Despite wariness about proposing yet another bureaucratic structure, the committee believes that a multitiered hierarchical management and coordination mechanism could provide a structure by which the relevant funding agencies would be encouraged to interact for improved communication and collaboration.
The synergies from interdisciplinary interactions provide the basis for innovative and exciting research that can lead to new discoveries and greater knowledge. As both the researchers, and the agencies that fund their research, seek to increase support for interdisciplinary research, the time is right for the earth science and public health communities to take advantage of the opportunity to promote true collaboration—there is no doubt that society will ultimately derive significant health benefits from the increased knowledge that will derive from research alliances.
The interface between the earth sciences and public health is pervasive and enormously complex. Collaborative research at this interface is in its infancy, with great potential to ameliorate the adverse health effects and enhance the beneficial health effects from earth materials and earth processes. The earth science and public health research communities share a responsibility and obligation to work together to realize the considerable potential for both short-term and long-term positive health impacts.