Search Results (3)

In recent years, attention has been paid to finding eco-friendly products that could represent an alternative for the chemicals usually used during conservation procedures. In the field of the devitalization of biological patinas, the most studied products are essential oils (EOs). Several works tested EOs in vitro on microorganisms isolated from stone artifacts but few applied these products on real artworks colonized by a complex patina. In the present work, the biocidal effect of two EOs (cinnamon bark and oregano) and two EO-based products (Biotersus and Essenzio) was compared to that of three chemical biocides commonly used in the conservation of stone artifacts (Biotin R1+R2, NewDes50, and Preventol RI50). The products were applied by brush in situ on a marble slab characterized by a green patina. The biocidal activity was evaluated by analyzing the chlorophyll fluorescence and quantifying ATP through biochemical tests. Furthermore, the products’ interference with stone was evaluated by colorimetric measures on sedimentary rock samples. The results indicate that chemical biocides exhibited biocidal activity of greater than 99.5% with a single application, while cinnamon oil (at a 1% concentration) and Essenzio required two applications to achieve the same level of efficacy. Conversely, oregano oil and Biotersus were not able to effectively reduce microorganism vitality, even with repeated applications. Full article

The 17th Century Casa a Ponente of Palazzo Rocca Costaguta’s wall provided an opportunity for an evaluation based on a Life Cycle Assessment (LCA) approach of conservation treatments aiming at removing biological colonization from built heritage surfaces. The investigated surfaces were historic plasters partially covered by a patchy green patina due to biofilm recolonization soon after a previous biocidal treatment. Areas of the biocolonized wall were treated by conservation professionals according to both conventional and “green” (i.e., exploiting natural active principles) biocidal products, including Preventol RI 50 (active substance benzalkonium chloride), Essenzio (active substance essential oregano oil), and hydrogen peroxide. Upon treatment, LCA analysis was conducted to evaluate the environmental impact of the different solutions, including a no-treatment option. LCA analysis was based on on-site investigations of the untreated wall surface with and without biofilm and following the biocidal treatment. The conservation treatment’s impact on the mineral substrate was based on digital microscopy, colorimetry, and water contact angle measurements via an innovative portable method. The results highlighted the impacts of the different biocidal treatments, which, in some cases, have not completely removed the biofilm and, in some cases, have altered the surface properties of the plaster. This pointed out the opportunity to re-think conservation strategy, including LCA analysis as a complementary tool to assess the environmental impact of the different conservation treatments and procedures. Full article

This study is aimed to compare, through laboratory experimentations, the efficiency of UV-C irradiation and an essential-oils-based product as tools to reduce the biofilm identified in a semi-hypogeum room located in the archaeological park of Baia, Italy. During this study, the autotrophic component of the original biofilm, mostly composed of Chlorophyceae and Cyanophycean, was isolated in the laboratory, while simultaneously, the composition of the pigments used for the fresco paintings was examined in situ through X-ray fluorescence. These examinations were necessary for the creation of test samples that were similar to the original surfaces and used for subsequent experiments. The plaster testers were contaminated with artificial biofilm, exposed to UV-C at a distance of 80 cm for a fixed time interval and treated with ESSENZIO©, a product based on oregano and thyme essential oils, to eradicate the biological species. The treatment’s effectiveness was then assessed by employing optical microscopy and spectrometric techniques applied to the areas previously occupied by the biofilm on the different test samples. To obtain an additional parameter to evaluate the treatments efficacy, the concentrations of the photosynthetic pigments were also measured by spectrophotometry. Results showed that biofilms were successfully removed by the irradiation of the surfaces and by the essential-oils-based product at a dilution of 50% in demineralized water with a time of application of 1 h and 30 min; in addition, no visible change of the pigments used on the testers were observed, demonstrating the high efficiency of the treatments against biodeteriogens. The two methods and their different mechanisms of action have provided interesting aspects that suggest a combined strategy to contrast and prevent biological growth in archaeological contexts. Full article