by Mahgoub A. Ahmed, Mona F. Ali, Nabil A. Bader and Rafat Khalaphallah
ABSTRACT
The archaeological buildings in Upper Egypt are exposed to many deterioration factors. The wild pigeon that lives in Habu Temple (Luxor) is considered one of the most deterioration factors causing damage to the ar-chaeological buildings. Various mechanisms and forms of damage occur by wild pigeon. The current research aims to study the physical and chemical effects of wild pigeon’s excrements on sandstone and wall paintings. The analytical study by X-ray fluorescence (XRF) and X-ray diffraction (XRD) of wild pigeon’s excrement and paintings was conducted. USB digital microscope was used to examine wild pigeon droppings adhering to the surface of paints. The pH of wild pigeon excrements was measured using a pH meter. Analysis by XRD and XRF revealed a change in the chemical composition of painting components due to the reaction of the acidic excreta with sandstone and various painting components. This reaction led to the formation of sulfate and carbonate salts, which caused the decay of the archaeological paints and stones. Pigment minerals such as hematite (Fe2O3) for the red color and malachite (Cu2CO3(OH)2) for the green color were identified. The examination showed that the excrements were strongly adhered on the paint surface and penetrated into the inner painting surface. Excrements led to the detachment of pigment materials from paint surface and granular disintegration of sandstone. The pH of the excreta is changed over time. This study provides a greater under-standing of the effects of wild pigeon excreta on the archeological stone and paintings.
