Biological colonization on stone monuments: A new low impact cleaning method

In restoration and conservation practices, biocide treatments are considered one of the most practical approaches to remove biological colonization on artworks, including stone. Numerous studies have focused on the short- and long-term effects of these treatments and recently many alternative methods to reduce their potential hazards to human health and the environment have been proposed. In this study, a solvent gel containing dimethyl sulfoxide (DMSO), already used to clean paintings, was applied on colonized marble artifacts at the monumental cemetery of Bonaria (Cagliari - Italy) to remove biological patinas. The protocol efficiency was evaluated by scanning electronic microscopy, rugosimetric and colorimetric measurements and growth tests. A comparative study also was performed to validate the method using biocides currently used in conservation. The results demonstrate that DMSO solvent gel is efficient at removing patinas on stone, of low impact, easy to use, inexpensive and can be considered a more practical alternative to biocide treatments.