LAUSR

Abstract Biodeterioration is a topic of ever-growing concern and is particularly relevant in the context of cultural heritage conservation, since artworks and monuments provide diversified ecological niches for microorganism colonization. Despite all the gathered knowledge in recent years, current established norms and accepted contamination thresholds have a prominent focus on human health and air quality preservation. Nonetheless they still are not enough or are not adequately applied for cultural heritage preservation. In the light of this study within a very important Museum from Coimbra (Portugal), the current knowledge and accepted norms are discussed. Despite the meticulous control of environmental parameters inside this art repository, the presence of fungal colonies was unexpectedly detected on wooden sculptures and paintings that were deposited inside a custom-built room. Contaminated art objects were sampled for fungal isolation and identification, along with seasonal indoor air sampling, for a one-year period. Molecular biology methods complemented with morphological observation were used for the identification of fungal organisms. Direct sampling of 8 contaminated paintings allowed the retrieval of 10 fungal isolates (3 different genera and 4 different species). In addition, 19 fungal isolates (5 different genera and 9 different species) were retrieved from 7 contaminated wooden sculptures. The air sampling process provided a total of 150 isolates (24 different genera and 43 different species), from which the most common genera were Aspergillus, Cladosporium and Penicillium, and the most frequent species were Aspergillus versicolor, Cladosporium cladosporioides, Penicillium copticola and P. corylophilum. Although the number of airborne CFU was considerably low in all seasons, some fungal species with known biodeterioration capability and adverse human health effects were found. The relevance of air contamination monitoring as a single tool for biodeterioration risk assessment is discussed, as are the currently available norms and recommendations. Preventive measures are advised and considerations are made regarding potentially more effective approaches.