Natural science collections include objects that demonstrate physical links to the natural world around us. The ongoing preservation, care and study of these collections help us gain a better understanding of all the world has to offer.
Natural science collections are built up of all the different types of animals, plants and geological specimens found around the world. Taxidermy mounts, animal skeletons, fluid preserved specimens, minerals, gems, fossils and shells are some of the types of collection areas found in natural science museums.
Common types of deterioration
Materials found in natural science collections can vary greatly, including natural materials (plant fibres, resins, wood) to inorganic materials (stone, ceramic). As some natural science collections may include very fragile items such as feathers, skin and turtle shell, older objects may face many preservation issues to do with the inherent instability of organic materials.
Biological damage such as mould and bacteria, or pest damage from rodents and insects can cause staining and structural damage to collections that have a high organic material content. Silver fish, clothes moths and wood-boring insects thrive in environments containing high relative humidity and feast on organic and animal-based materials.
Splitting, cracking and warping of organic materials such as wood, plant fibres, skins and textiles are common problems when humidity and temperature fluctuates in a storage or display environment.
Treatment of natural science collections often involves minimal intervention and instead focuses more on preventive conservation methods in order to make sure the storage and display requirements of the materials are met. This involves assessing and monitoring conditions within an environment such as light levels, temperature, humidity and air quality.
Maintaining a stable humidity and temperature means organic materials are less at risk of embrittlement and accelerated deterioration. Using conservation grade storage and display materials that are acid-free, chemically inert and provide adequate physical support to the objects within are an important part of the role of a conservator.
When objects have deteriorated, are broken or have areas of loss, it requires decision-making on behalf of the conservator and the owners of the cultural material. A conservator’s role in this instance is to stabilise and reduce physical or chemical damage rather than ‘restore’ the object to its original condition.
In regards to natural science specimens that may be deformed or warped, conservators often use treatments of humidification. Light application of deionized water using ultrasonic technology to humidify can return the natural shape of organic materials, such as plant fibres in basketry or the shape of an animal’s ear.
Integrated Pest Management (IPM) is another important component of preventive conservation. Managing and reducing the opportunity for pests to access a collection in the first place is significant, although freezing objects can kill biological activity such as insects and mould.
Natural science collections should be treated with particular care due to the possibility of contamination with hazardous materials. Many objects such as taxidermy mounts will have been treated to prevent mould or pest infestation with pesticides and preservatives such as ethylene oxide, arsenic, dichlorvos, tobacco, camphor, strychnine, mercuric chloride, naphthalene, paradichlorobenzene (PDB), DDT, methyl bromide, cyanide and compounds of cyanide.
Due to the difficulty of knowing exactly what kind of toxic material might be present in a specimen, it is recommended to treat any biological specimen collected and prepared prior to 1980 as containing arsenic. The assumption an object is contaminated is always preferable to the accidental handling of arsenic. Ideally, such objects should be enclosed in a clear polyethylene bag with a label stating “possible arsenic hazard”, until it is able to be confirmed by consulting a professional.
Australian Museum conservator, Sheldon Teare invites the Sydney Morning Herald’s Peter Munro into his lab to explain the process of conserving historic museum specimens for the Wild Planet exhibition.
AICCM has a Special Interest Group for those interested in the conservation of objects, including natural science collections. Join this group, contribute to its activities, or speak to a specialist conservator.