Nitrogen for Biodeterioration Control on Museum Collections

Abstract

A method of microbial control and insect eradication has been developed using inert gases, nitrogen, and low relative humidity in a hermetically sealed case. Radioactive tracers were used to assess the biological activity of fungal contaminants inoculated on new parchment samples and exposed to a nitrogen atmosphere at fixed relative humidities. Bacterial growth was evaluated by membrane filtration and epifluorescence microscopy using ancient parchment under different levels of relative humidity and oxygen. The lethal effect of nitrogen as anoxant for eliminating insect populations was determined using Drosophila melanogaster (fruit fly) as an experimental model. A significant decrease of the biological activity and bacterial growth was found on contaminated material exposed to low levels of relative humidities and oxygen concentrations. Using D. melanogaster as a model it was found that a nitrogen atmosphere under controlled temperature and relative humidity is an effective means for eradicating all the stages of insect life cycle including eggs. Similar results were obtained using the termite species Cryptotermes brevis, the West Indian drywood termite, often found in museums.