岩鸽排泄物对壁画损害特征研究

鸟类排泄物是造成石窟寺壁画、彩塑污染的主要因素之一,科学剖析鸟类排泄物对壁画的损害特征是此类污染物有效清除的前提。本研究利用傅里叶变换红外光谱(FTIR)、气相色谱-质谱联用(GC-MS)、X射线衍射(XRD)等方法分析了炳灵寺石窟壁画表面岩鸽排泄物成分,采用扫描电镜-能谱仪(SEM-EDS)、便携式显微镜、偏光显微镜(PLM)表征了鸟类排泄物对模拟壁画的微观损害特征。结果表明,岩鸽排泄物成分主要由尿酸、纤维素、多肽类有机物,以及以石英为主的无机盐组成。排泄物造成壁画覆盖污染、颜料层和地仗层侵蚀、颜料颗粒间原始粘附结构破坏,导致颜料层起甲、脱落,可溶盐活动及其他生物侵蚀。研究结果对于古代壁画的科学保护与修复具有指导意义。

Research on the damage characteristics of Columba rupestris excrement to wall paintings

Bird excrement is one of the main factors causing the pollution of wall paintings and painted sculptures in grotto temples. Scientific analysis of the characteristics of damage of bird excrement to wall paintings is the premise of effective removal of such pollutants. In this study, Fourier transform infrared spectrometry (FTIR), gas chromatography-mass spectrometry (GC-MS) and X-ray diffraction (XRD) were used to analyze the composition of the Columba rupestris excrement on the surface of the wall paintings at Binglingsi Grottoes. Scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), electronic digital microscopy and polarized light microscopy (PLM) were used to characterize the microscopic damage characteristics of bird excrement on the simulated wall paintings. The results show that the excrement of Columba rupestris was mainly composed of uric acid, cellulose, polypeptide organic matter, and inorganic salts (mainly quartz). The excrement caused the cover pollution of wall paintings, erosion of the pigment layer and ground layer, and destruction of the original adhesion structure between pigment particles, resulting in the peeling and shedding of the pigment layer, soluble salt activity and other biological erosion. The research results have guiding significance for the scientific protection and restoration of ancient wall paintings.