Zniszczenia mikrobiologiczne zbiorów na tle warunków przechowywania w wybranych bibliotekach i archiwach w Polsce

The aims of this work were to assess the biodeterioration of library and archive collections as well as to identify the causes of the destructive processes. The investigation was carried out in five selected storerooms with particular attention being paid to the accumulation of moisture on wall barriers. The measurements of air relative humidity (RH) and temperature as well as the assessment of the biodeterioration of the collections were performed. The samples taken from the objects attacked by microorganisms were microbiologically tested. A direct dependency between the defects of buildings and the accumulation of moisture on wall barriers was confirmed. The source of moisture accumulation in some storerooms were rainwater penetrating the interior of the rooms through a leaky emergency door, through cracks in roof or terrace coverings or water from the overfilled manholes. The floodings resulted in the water stains on walls and ceilings, flaking of paint coatings, or sometimes colourful deposits of moulds or salts. The average values of the air RH in the examined storerooms ranged between 46.0% and 47.4%. However, it was noted that this parameter highly fluctuated up to 30% RH during a year. The average temperatures were between 19.5 and 21.0ºC, which means they were around 1.5 to 3ºC higher than temperatures recommended for library and archive collections. The temperature values were also variable and, to a large extent, dependent on the outdoor conditions. Around a quarter of collections in all examined storerooms was, to a larger or lesser degree, damaged by living organisms (fungi, insects and rodents). Some of the threats were still up-to-date, e.g. the attack of insects in one of the storerooms. However, a great number of other damage, in particular caused by microorganisms, has its beginnings in the past and the microorganisms responsible for the damage may have been inactive for a long time now. Hence, it is very difficult to find a correlation between the results of microscope examinations of deposits taken from the attacked places and the results of cultivation of microorganisms from the same spots. The collections had been stored in the examined storerooms for a relatively short period of time between 10 and 30 years. Their condition of preservation was, to a larger degree, affected by violent conditions (storing in basements, storing in attics, moving places, wars) and moisture, which had accumulated for decades before the collections were placed in the examined storerooms.