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XIII Summary of Needs and Priorities HOWARD C. HOPPS, Chairman William H. Allaway, Kenneth C. Beeson, George K. Davis, Richard M. Forbes, Donald J. Horvath, Joe Kubota, Henry L. Lucas, Gennard Marrone, Walter Mertz, Paul M. Newbeme, Harold H. Sandstead, Robert Tardiff, E. J. Underwood, A. Wouter Voors, JohnS. Webb The broad, general recommendations made in this section supplement the more specific ones presented by the various work groups. They overlap the conclusions and recommen- dations developed from Overview Work Group considera- tions, but extend and expand on these in the context of perspective gained during the Workshop; moreover, they reflect direct participation by members of all eight work groups. Recommendations Although determination of the environmental levels of the trace elements and of the geochemical and other factors that influence these levels is essential, the value and meaning of these levels are limited without satisfactory data on the minimum and maximum intakes compatible with the long- term health and weU-being of man. The amounts of trace elements responsible for severe deficiency or acute intoxica- tion are, for the most part, well established, but the bio- logical consequences of continuous exposure to the lesser amounts present in the modern environments are largely unknown. This knowledge is particularly pertinent in dealing with such harmful elements as arsenic, cadmium, lead, and mercury and with such marginally deficient ele- ments as zinc and chromium. Long-term studies of man are therefore urgently needed to assess the minimum ade- 103 quate and maximum safe levels of intake of the trace ele- ments from the food, the water supply, and the atmosphere. I. Two primary approaches to determine cause-effect relationships between geochemical environment and disease are, fust, identify geographic areas of anomalously high or low trace element content, then attempt to correlate these with disease that occurs in that area; or, look ftrst for ap- propriate health and disease problems, then search for possible trace element relationships. The disease-oriented approach is most likely to be effective, as judged from past experiences, and deserves major emphasis. Both the ap- proaches are useful, however, and should be pursued simul- taneously. 2. In connection with Recommendation 1, it is particu- larly important to produce maps showing the distribution of disease in animals, especially humans, emphasizing quantitative aspects of occurrence (or rates), severity, duration, and related factors. 3. It is also important to produce additional comprehen- sive broad-area maps showing the distribution of certain specific trace elements, as has been done very effectively with selenium. In preparation of such maps, there should be an effort to indicate bioavailability in addition to mere content, as shown by conventional quantitative analysis. 4. A series of short monographs should be produced
104 THE RELATION OF SELECTED TRACE ELEMENTS TO HEALTH AND DISEASE to consider and make available the guiding principles and recommended information on sampling and analysis of pertinent environmental materials. 5. Analytical data should be systematically accumulated on appropriate human samples-such as blood, urine, and hair-taken in various regions of the country, and, when appropriate, supplemented with such physiologic data as body build and blood pressure, along with a variety of such clinical pathologic data as hemoglobin values, and hospital diagnoses. 6. Now that it is feasible, it is very important to focus on serious human diseases in a manner that represents a truly multidisciplinary effort. An excellent approach would be to pursue multidisciplinary reconnaissance studies in those geographic areas with, for example, a relatively high incidence of cardiovascular disease, in comparison to other- wise comparable areas where deaths from cardiovascular disease are relatively low. Experiments should be designed to include correlative studies, in depth and in the same time and place framework, by geologists, geochemists, soil and plant scientists, veterinarians, and physicians to identify correlations that may prove to have a cause-effect relation- ship. Such an approach has been initiated in Georgia. Ob- viously, a considerable amount of such research effort would be directed toward determining the precise course of various trace elements, from their parent materials to the soil and into the food chain, to reach man. This would in- clude considerations of recycling and the character and in- fluence of various concentrated waste materials. 7. In addition to the reconnaissance surveys described in Recommendation 6, certain physiographic units should be selected for detailed multidisciplinary studies-such as drainage basins of small rivers-that simultaneously involve geochemists, soil, plant, and biomedically-oriented scien- · tists. A more detailed description of the recommendation on studies of selected physiographic units may be found in Chapter I under Conclusions. 8. A profitable approach for research on biological ef- fects of specific trace elements would be to divide trace elements into two major groups, cationic and anionic, and focus on several of the anionic elements, because these cross most membranes easily and are thus much less af- fected by homeostatic mechanisms. Certain cationic trace metals could also be included in the studies-particularly those closely associated with bulk cationic metals, which, in a sense, slip in with the bulk elements. As to priority, individual trace elements should be considered in terms of their direct importance to man and how much is already known about them. Applying these criteria, iron and chro- mium, for example, would not rate a high priority, whereas fluorine, selenium, lithium, and cadmium would. 9. Of all the specific trace elements considered during the Workshop, further studies on the interactions between cadmium and zinc (and possibly copper) and their relation- ships to cardiovascular disease were given highest priority. Moreover, investigation of these three elements would pro- vide valuable basic information about problems of inter- action. 10. These recommendations have not stressed the im- portance of research at a cellular level because the Work- shop participants felt that this area was being adequately supported by agencies such as the National Institutes of Health. II. Finally, it was the consensus that additional work- shops of the Asilomar type should be carried out. As at Asilomar, these workshops should involve a comprehensive, multidisciplinary approach to (I) other specific trace ele- ments important to man; (2) further considerations of rock- water-soil-plant-animal interfaces; (3) sampling and analy- ses in the context of experimental design; ( 4) systems anal- ysis, experimental design, and mathematical modeling; (5) automatic data. storage, retrieval, manipulation, and (form of) output; and (6) communication. Additional Conclusions and Recommendations The workshop participants also agreed on the following ad- ditional conclusions and recommendations: I. Systems models can be very valuable in showing de- ficiencies in critical areas and gaps in knowledge-in ex- plicit terms, "Here we do not have, but need to know." 2. Regarding allowable levels of pollution, sometimes pollution helps, raising levels that are too low; sometimes, if the natural base level is critically high, virtually no pol- lution is tolerable. 3. Not only is it important to identify areas requiring activity, we must also describe mechanisms for action. 4. Paleopathologic data are needed to help defme trends and rates of change. 5. We need more data about fossil fuels, with careful analyses of samples {rom different parts of the world. 6. Regarding characteristics of water, we need to focus more attention on aquifers. 7. Bench-mark samples, including animal tissue, need to be preserved for review and for unanticipated future use.
ASILOMAR WORKSHOP PARTICIPANTS William H. Allaway, Plant, Soil, and Nutrition Laboratory, Agricultural Research Service, Ithaca, N.Y. Ernest E. Angino, Department of Geology, University of Kansas, Lawrence James E. Banta, School of Public Health, University of Hawaii, Honolulu Kenneth C. Beeson, Consulting Soil Scientist, Sun City, Ariz. Richard G. Burau, Department of Soils and Plant Nutrition, University of California, Davis Helen L. Cannon, Branch of Exploration Research, U.S. Geological Survey, Denver, Colo. George K. Davis, Department of Sponsored Research, University of Florida, Gainesville Michael Fleischer, Branch of Regional Geochemistry, U.S. Geological Survey, Washington, D.C. Richard M. Forbes, Department of Animal Science, University of Illinois, Urbana Wdliam Fulkerson, ORNL-NSF Environmental Program, Oak Ridge National Laboratory, Tenn. Edward D. Goldberg, Scripps Institution of Oceanography, University of California, San Diego K. Michael Hambidge, Department of Pediatrics, University of Colorado Medical Center, Denver Robert C. Harriss, Marine Laboratory, Florida State University, Tallahassee Howard C. Hopps, Department of Pathology, University of Missouri Medical Center, Columbia Donald J. Horvath, Department of Animal and Veterinary Sciences, West Virginia University, Morgantown Richard J. Janda, Water Resources Division, U.S. Geological Survey, Menlo Park, Calif. Everett A. Jenne, Water Resources Division, U.S. Geological Survey, Menlo Park, Calif. Roger Jorden, Department of Civil and Environmental Engineering, University of Colorado, Boulder Lennart Krook, New York State Veterinary College, Cornell University, Ithaca, N.Y. Joe Kubota, Plant, Soil, and Nutrition Laboratory, Soil Conservation Service, Ithaca, N.Y. Herbert A. Laitinen, Department of Chemistry, University of Illinois, Urbana Hubert W. Lakin, Branch of Exploration Research, U.S. Geological Survey, Denver, Colo. Henry L Lucas, Biomathematics Program, North Carolina State University, Raleigh Gennard Matrone, Department of Biochemistry, North Carolina State University, Raleigh Walter Mertz, Nutrition Institute, Agricultural Research Service, Beltsville, Md. George H. Morrison, Department of Chemistry, Cornell University, Ithaca, N.Y. 0. H. Muth, Department of Veterinary Medicine, Oregon State University, Corvallis Paul M. Newbeme, Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge Boyd L O'Dell, Department of Agricultural Chemistry, University of Missouri, Columbia James E. Oldfield, Department of Animal Science, Oregon State University, Corvallis James 0. Pierce, Environmental Trace Substances Center, University of Missouri, Columbia Harold H. Sandstead, Human Nutrition Laboratory, Agricultural Research Service, Grand Forks, N.D. Robert Tardiff, R. A. Taft Sanitary Engineering Center, Environmental Protection Agency, Cincinnati, Ohio E. J. Underwood, W. A. Office of the Executive, csiRO, Wembley, Western Australia A. Wouter Voors, Department of Epidemiology, University of North Carolina, Chapel Hill John S. Webb, Department of Geology, Imperial College of Science and Technology, London Warren Winkelstein, Jr., School of Public Health, University of California, Berkeley Bobby G. Wixson, Environmental Research Center, University of Missouri, Rolla Staff Albert N. Bove, Division of Earth Sciences, National Research Council Susan D. Vick, Division of Earth Sciences, National Research Council 105
