Biocides for the Control of Mosses on Stone Cultural Relics

Controlling biodeterioration is a worldwide necessity for the preservation of cultural heritage. Biocides are the most effective compounds used for heritage protection of stone; however, their specific efficacy, performance over time, interference with cultural heritage materials, and potential hazards are still unclear. In this work, we test and evaluate a large number of biocides to address the degradation of stone cultural relics by mosses. The quantitative and qualitative evaluations of biocide efficiency were performed by chlorophyll fluorescence (ChlaF) measurements and confocal microscopy. Surprisingly, traditional herbicides (glyphosate, glufosinate-ammonium) and metal oxide nanoparticles (CuO, ZnO) with antibacterial effects do not affect mosses. However, some plant hormones and essential oils showed good effects at all stages of moss growth. Meanwhile, biocides were also tested on artificial simulated rocks to see if they change their properties. It turns out that biocides containing copper ions can cause chromaticity changes on the rock surfaces. In the end, a total of six efficient and safe biocides were obtained, which will play a good role in biological control for cultural heritage protection.