18.01.2017 change 18.01.2017

History smelling of mould

Parchments, silk fabrics, and even the file of TW "Bolek" have been examined by scientists to see if these objects were threatened by mould, destructive for old documents and works of art. They analysed the smell, indicating the activity of mould attacking historical object.

In the past two years researchers examined various objects from many places in Poland, including 23 churches and monasteries in Kraków. "We tested various objects - parchments, silk and wool fabrics, old books, on which there were changes indicating the presence of mould. We checked whether the mould on each of these objects is active or inactive" - told PAP Tomasz Sawoszczuk from Cracow University of Economics.

The researchers conducted their analysis using a completely new method they had developed: "sniffing" historical objects. They analysed the odour released by mould in the objects.

First - in the framework of the project financed by the National Science Centre - they analysed the "smells", or mixtures of organic compounds emitted by historical objects attacked by mould. Of the approximately 150 volatile organic compounds emitted by various species of fungi growing on samples of historical materials, they selected three groups of compounds. These compounds indicated biological activity of microorganisms, so-called bio-indicators of metabolic activity of mould. In total, they distinguished approximately 12 compounds indicating the presence of active mould.

They allow you assess the risk of destruction of the object by the growing mould. A sample of the mixture of compounds released from the affected surface of the historical object is collected and analysed. The presence of bio-indicators shows whether mould is present in the object in an active, growing form, or not.

What does such a test involve? "We have a fibre, at the end of which there are three different sorbents, and touch the affected spot with it" - the researcher explained. Chemicals present on the object attach to the fibre. Enriched with valuable chemical information, the fibre is heated to a temperature of 250 deg. C in the laboratory, and the aroma is released directly into gas analyser - gas chromatograph.

"Based on this measurement, we can give an answer to a conservator: whether the change that he sees on the surface of, for example, a page from an old book, is an active fungus that will destroy the object, or it is an inactive fungus and there is no need for intervention and disinfection. In some cases, such as silk fabrics, such disinfection is very disadvantageous and may even advance the material degradation" - described Dr. Sawoszczuk.

The results of the test in 93 percent cases confirmed or ruled out the presence of active mould. In the remaining 7 percent cases the amount of compounds was so small that it was impossible to detect anything. The results of the method have been verified with standard microbiological tests.

"Currently, conservators use microbiological and genetic methods for historical objects. However, in their case, the response time is much longer. A sample collected from the surface of the object has to be cultured for about 5-7 days. Only after all this time we get the result. In the case of molecular methods, collected material must be proliferated and marked. In the case of our method, in a few hours we can answer whether the mould is activate, and whether the object must be disinfected and isolated" - explained the researcher.

During the development of the method, the researchers collaborated, among others, with the National Museum in Kraków; Cathedral Museum at Wawel; Academy of Fine Arts in Warsaw; Faculty of Fine Arts of the Nicolaus Copernicus University; University College of London; Geological Survey Department of the Ministry of National Infrastructure of Israel.

"This method, although it can be considered new, enjoys high credibility among archivists and art conservators. It has been included among the methods, which were used to examine the TW Bolek files after they were transferred to the Institute of National Remembrance in Warsaw" - the researcher told PAP.

PAP - Science and Scholarship in Poland, Ewelina Krajczyńska

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