Featured Research

from universities, journals, and other organizations

Methodology applied to historical walls may explain why moss gathers and how paint blackens

Date:
September 13, 2011
Source:
Elhuyar Fundazioa
Summary:
For the correct restoration of deteriorated works of cultural heritage, it helps to know what causes the degradation in the first place. There are studies that characterize these types of damage in detail, but that rarely touch on the origin and development of the deterioration. A chemist has now come up with an analytical methodology with the intention of filling this need.

For the correct restoration of deteriorated works of cultural heritage, it helps to know what causes the degradation in the first place. There are studies that characterise these types of damage in detail, but that rarely touch on the origin and development of the deterioration. Chemist Maite Maguregui has come up with an analytical methodology with the intention of filling this need: considering the material of origin of the historical heritage and the product that substituted over time (the decay product), in order to appropriately understand the development of the degradation process.

She presented her PhD thesis at the University of the Basque Country (UPV/EHU), with the title, A new diagnosis protocol to assess the impact of environmental stressors on historical bricks, mortars and wall paintings.

Ms Maguregui characterised the deterioration caused by infiltrating water, atmospheric acid gases and microorganisms, and observed that human intervention has had much to do with all this. Specifically, she applied this methodology to bricks, mortars and wall paintings; amongst others the paintings in dwellings of old Pompeii. Ms Maguregui and her colleagues have published an article in Analytical Chemistry based precisely on the work undertaken in the Roman city and entitled Thermodynamic and spectroscopic speciation to explain the blackening process of hematite formed by atmospheric SO2 impact: the case of Marcus Lucretius House (Pompeii).

Diversity of techniques

This methodology included different analyses. To begin with, use was made of non-invasive spectroscopic techniques in order to characterise both the original compounds and the decay products. Moreover, microdestructive techniques were applied to the quantification of soluble salts, given that the considerable presence of these causes damage to works of cultural and historical heritage. Chemometry was employed for treatment of data and, in order to understand the development of the process of deterioration, chemico-thermodynamic models were used. In the final part, Raman spectroscopy and depth profiling were used, with the aim of determining the distribution of the components, both of the original compound and of the decay products.

With this analysis, it was seen that sulphur dioxide and oxides of nitrogen are amongst the principal causes of deterioration -- compounds that are found in industry, automotion, food industry, and so on. Thus, it is human activity that is responsible for the deterioration of cultural and historical heritage.

Also thanks to this analysis, Ms Maguregui concluded that environmental factors do not negatively affect heritage works in an isolated manner, but each item can deteriorate in diverse ways. In Pompeii, sulphur dioxide had damaged plaster, on which, in turn, moss grew. It was thus concluded in the thesis that there may be a nexus between these two phenomena. In fact, other researchers have already mentioned that gypsum could be a good nutrient for colonising microorganisms. Thus, the sulphation caused by sulphur dioxide on the plaster attracts microorganisms, which is why moss grows and accumulates.

Acceleration of the process

The data gathered with the new methodology enabled the researcher to make hypotheses about how the process takes place and what mechanisms take part in each case. But, besides explaining this at a theoretical level, she has validated it. She copied the supposed process of deterioration in some of the cases, applying it experimentally using a series of techniques that accelerated the development of the process, a series which the researcher, herself, designed.

Concretely Ms Maguregui carried out an experiment on the wall paintings of the Marcus Lucretius House in Pompeii. The zones that originally contained red haematites were blackened, as these had been substituted by magnetite and iron (III) sulphate nonahydrate. According to the researcher, both decay products would have appeared as a result of sulphur dioxide; a hypothesis that she verified thanks to the experimentation accelerating the process. As a result these zones of the wall paintings had blackened due to effect of human activity on the environment.


Story Source:

The above story is based on materials provided by Elhuyar Fundazioa. Note: Materials may be edited for content and length.


Cite This Page:

Elhuyar Fundazioa. "Methodology applied to historical walls may explain why moss gathers and how paint blackens." ScienceDaily. ScienceDaily, 13 September 2011. <www.sciencedaily.com/releases/2011/09/110913092418.htm>.
Elhuyar Fundazioa. (2011, September 13). Methodology applied to historical walls may explain why moss gathers and how paint blackens. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2011/09/110913092418.htm
Elhuyar Fundazioa. "Methodology applied to historical walls may explain why moss gathers and how paint blackens." ScienceDaily. www.sciencedaily.com/releases/2011/09/110913092418.htm (accessed September 30, 2014).

Share This



More Fossils & Ruins News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

2,000 Year Old Pre-Inca Cloak on Display in Lima

2,000 Year Old Pre-Inca Cloak on Display in Lima

AFP (Sep. 27, 2014) A 2,000 year-old Pre-Inca cloak that is believed to represent an agricultural calendar of the Paracas culture is on display in Lima. Duration: 00:39 Video provided by AFP
Powered by NewsLook.com
Original Mozart Sonata Manuscript Found in Budapest

Original Mozart Sonata Manuscript Found in Budapest

AFP (Sep. 26, 2014) Considered lost for over two centuries, the original manuscript of one of the most famous works of Mozart's Sonata in A major has been uncovered in a library in Budapest. Duration: 01:04 Video provided by AFP
Powered by NewsLook.com
Underground Art Reveals WW1 Soldiers' Hopes and Fears

Underground Art Reveals WW1 Soldiers' Hopes and Fears

AFP (Sep. 25, 2014) American doctor and photographer Jeff Gusky reveals the underground quarries used by the soldiers of World War One, and the artwork they left behind which illustrates their hopes and fears. Duration: 02:15 Video provided by AFP
Powered by NewsLook.com
Raw: Ice Age Wooly Mammoth Remains for Sale

Raw: Ice Age Wooly Mammoth Remains for Sale

AP (Sep. 23, 2014) A rare, well-preserved skeleton of a woolly mammoth is going on sale at Summers Place Auctions hope the 11.5-foot tall, almost intact specimen will fetch between $245,000 to $409,000. (Sept. 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins