Protection of Mayan Archeological Sites in Southern Mexico from Biodeterioration

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9710577 Mitchell There is an urgent need to protect Mayan archeological sites in southern Mexico from further deterioration. The combination of high humidity and temperature, together with increased tourist activity, is causing rapid deterioration of these important historic sites. Much of the material used in the construction of Mayan buildings was soft limestone, which is mechanically weak and susceptible to biodeterioration. The objectives of this research will be to determine the degree of susceptibility of these materials to degradation by microbial activity and to test methods for protection of the building materials against further deterioration. This research program will be carried out in close cooperation with the Escuela de Ingenieria, Universidad del Mayab. In the first phase of the research we will determine the nature and activity of the microorganisms on limestone samples taken from archeological sites. Qualitative analysis of the microflora will utilize both physiological and genetic methods. Quantitative determination of the attack of the stone will involve image analysis of the microflora and measurement of calcium release from the stone. Degradation studies will be made on the stone from a number of different sites. In the second phase of the research both artificial polymeric consolidants and biocides will be tested for their ability to protect the limestone. AR polymers will be tested under a variety of environmental conditions for susceptibility to biodegradation. Electrochemical impedance spectroscopy will be used as a primary analytic tool. Biocides to be tested will be environmentally acceptable and will need to be compatible with the consolidants. The final phase of this project will be to test the protective ability of combinations of consolidants and biocides in the field. Treated stone samples will be placed at different test sites with varying temperature, humidity, and organic carbon deposition. Analysis will incl ude protection against growth of fungi and bacteria, deterioration of the polymer, and degradation of the underlying stone. The significance of this project will be to provide information about the mechanisms of deterioration of Mayan archeological sites. The research will provide information about methods for protecting these sites. It is expected that the research will help to provide protection of these important historic sites in southern Mexico and other similar areas. In addition, we expect that graduate students and post-doctoral scholars from Escuela de Ingenieria, Universidad del Mayab will spend time at Harvard, and that we will assist in their training. ***