Application of Inorganic Nanomaterials in Cultural Heritage Conservation, Risk of Toxicity, and Preventive Measures

Abstract

Nanotechnology has allowed for significant progress in architectural, artistic, archaeological, or museum heritage conservation for repairing and preventing damages produced by deterioration agents (weathering, contaminants, or biological actions). This review analyzes the current treatments using nanomaterials, including consolidants, biocides, hydrophobic protectives, mechanical resistance improvers, flame-retardants, and multifunctional nanocomposites. Unfortunately, nanomaterials can affect human and animal health, altering the environment. Right now, it is a priority to stop to analyze its advantages and disadvantages. Therefore, the aims are to raise awareness about the nanotoxicity risks during handling and the subsequent environmental exposure to all those directly or indirectly involved in conservation processes. It reports the human–body interaction mechanisms and provides guidelines for preventing or controlling its toxicity, mentioning the current toxicity research of main compounds and emphasizing the need to provide more information about morphological, structural, and specific features that ultimately contribute to understanding their toxicity. It provides information about the current documents of international organizations (European Commission, NIOSH, OECD, Countries Normative) about worker protection, isolation, laboratory ventilation control, and debris management. Furthermore, it reports the qualitative risk assessment methods, management strategies, dose control, and focus/receptor relationship, besides the latest trends of using nanomaterials in masks and gas emissions control devices, discussing their risk of toxicity.

Evaluation of Eco-Friendly Consolidating Treatments in Pugliese Tuff (Gravina Calcarenite) Used in Italian Heritage Buildings

“…The treatment with nanolimes is proposed as effective in consolidating damaged areas, although it is less effective than the double-applied bioconsolidant in this case under study. However, this type of treatment with nanoparticles can present risk of toxicity, according to some authors [58].…”

“…Some authors point out that nanotechnology may have contraindications with nature [58], which is why it is important to know and try other eco-friendly alternative treatments, such as bioconolidants or lime water.…”

Recent Advances in the Application of Metal Oxide Nanomaterials for the Conservation of Stone Artefacts, Ecotoxicological Impact and Preventive Measures

“…Nanomaterials dispersed in a solvent or mixture of solvents can be applied on building materials through three procedures: brushing, immersion, and spraying. In the case of application through immersion, the piece can be removed from the area and placed in a solution containing a mixture composed of nanomaterials for impregnation through capillary rise [31]. The application of coating through spraying processes can be considered the most hazardous procedure [168], as nanomaterials can enter into the body during the application process through the skin, mainly via the face, hands, and arms, in addition to possible access through the eyes, nose, and ears [31].…”

“…However, although on the one hand these nanomaterials possess discrete self-cleaning properties, they possess a certain toxicity as well. In fact, over the years an increasing number of studies have pointed out the risks of nanotoxicity, including mortality rates, new diseases linked to contact between nanomaterials and the human body, and commonly, impacts on other living beings [31].…”

New Biocide Based on Tributyltin(IV) Ferulate-Loaded Halloysite Nanotubes for Preserving Historical Paper Artworks

“…Inorganic nanomaterials are promising as an emerging strategy for the conservation of cultural heritage materials, although specific risks of toxicity should be considered [19]. In this context, clay minerals such as imogolite have exhibited antibacterial properties attributed to their inner Al-rich surfaces and the sorption of essential metals such as Fe, Co, Cu, and Zn that are vital for bacterial survival [20].…”