Gamma Irradiation and Documentary Heritage: A Preliminary Study on the Effects of Gamma Irradiation on Historical Paper in Ecuador

Quito, recognized as the first UNESCO World Cultural Heritage Site, holds a vast documentary legacy at constant risk of deterioration due to environmental, biological, and aging factors. Preserving these historical documents demands sustainable and non-invasive approaches. This study presents the first documented investigation in Ecuador on the use of ionizing radiation for the conservation of historical paper materials. Fifteen fragments, naturally detached from deteriorated documents housed in two major heritage repositories, the Biblioteca Nacional Eugenio Espejo and the Biblioteca Fray Ignacio de Quezada, were selected for analysis. Samples were irradiated with a Co-60 gamma source at doses of 4, 6, and 8 kGy at the “Francisco Salgado T.” Irradiation Center. To evaluate potential alterations, pre- and post-irradiation analyses were conducted using surface pH measurements, colorimetry (ΔE from CIELAB coordinates), and FTIR-ATR spectroscopy. The results showed no statistically significant changes in the analyzed parameters, suggesting that gamma irradiation at these doses does not compromise the structural or visual integrity of the paper. This work represents a pioneering step in Ecuador toward integrating scientific methods into cultural heritage preservation, supporting the safe application of ionizing radiation in the conservation of historical documents.