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Answer by labsupport on question Biological preserved specimens

Submitted by sat on 28 February 2020

Storage of preserved biological specimens

Traditionally, solutions of formaldehyde were used for preserving biological specimens.  Many old existing preserved biological specimens in schools contain formaldehyde and or other hazardous solutions. Schools are not prohibited from having biological specimens in formaldehyde, unless it is banned by their school jurisdiction or sector.  It should however be understood that there are risks associated with exposure to formaldehyde.  If your school has specimens in formaldehyde, it is important to be aware of the hazards and ensure that suitable controls are in place to reduce your risk of exposure. If the specimens in formaldehyde are in well-sealed jars the risk of exposure is very low. Preserved biological specimens may now be purchased in less hazardous solutions.

Storage advice for preserved biological specimens:

Evaporation of the storage solution may indicate that the seal on the jars is not adequate. If the specimens are stored in the classroom and the teacher is in the classroom all day every day, then they are more at risk of exposure to hazardous fumes than students who would probably only be in the classroom for a few lessons per week. The only way to determine if workplace exposure standards have been exceeded is to undertake air monitoring for formaldehyde. The most effective control to reduce the risk of exposure is to remove or eliminate the hazardous chemical.

If your specimens are in good condition: you may wish to keep them. A range of strategies could be used to minimise that risk of exposure such as:

If your specimens are in poor condition: then it may be best to arrange for disposal of the specimen and the solution, by a licenced chemical waste contractor. Consideration could be given to finding an alternative, such as specimens embedded in resin, which are very resilient to student handling.

If you do not know what the storage solution is: then you should not top up the jars, as you may be combining incompatible chemicals resulting in the generation of new substances that have unknown properties and unknown hazards, creating a potentially violent chemical reaction or damage to the specimen.

Note: Science ASSIST strongly advises against formaldehyde (methanal) being used in a school science setting. It is a Category 1 (known) human carcinogen, has acute toxicity, and is a Category 2 drug precursor. See references for further information. Formaldehyde is not included in the Science ASSIST List of recommended chemicals because of its acute health hazards, and because it is not regarded as essential or important to the science curriculum. 

Disposal of biological preserved specimens

The best way to dispose of biological preserved specimens is to arrange for disposal ‘as is’ from a licenced chemical waste contractor.

It is a good idea to combine a disposal of these with any other chemicals that need disposal. Science ASSIST recommends that you:

Previous Q&As

We refer you to some of our previous Q&As, that provide further information:

preserved specimens which contains detailed information about

Preserving sheep brains without formalin which contain detailed information about

Calf Foetus which contain detailed information about

References and further reading

Bocaege, E., Cooke, M., & S. J. M. M. Alberti, 2013. Endangered specimens, endangered skills: a museum conservation initiative. Papers on Anthropology22, 303-308.

‘Formaldehyde - technical fact sheet’, SafeWork NSW website,  (Accessed February 2020) (See Health effects and Exposure Standards and air monitoring)

‘Formaldehyde in laboratories’, National Industrial Chemicals Notification and Assessment Scheme (NICNAS) website,  (Accessed February 2020) (See ‘Recommendations’ and ‘Occupational exposure standard’)