A licenced waste disposal contractor is required to dispose of any mercury or mercury compounds. Although the mercury may be fully enclosed within the thermometer, the toxicity of mercury means there is no other way to dispose of it. These thermometers, as long as they are intact, do not pose any immediate concern. However, if they are put into use, there is a high likelihood that they could be broken, which would create a hazard. Mercury thermometers, which are no longer required and that are not broken, should be collected and securely stored in a container to protect them from damage until collection by a licenced waste disposal contractor.
If any thermometer has been broken, then care needs to be taken to collect the spilt mercury and glass. Information for collecting the spilt mercury can be found in an earlier Science ASSIST document on dealing with mercury spills and disposal, which can be found at Mercury Spills. In summary, the mercury must be collected using a mercury spill kit, sealed, labelled and stored for collection by a licenced waste disposal contractor.
Alcohol thermometers are recommended for use in schools for the temperature range 0° C to 110° C. Whilst mercury thermometers are more accurate, in most circumstances, such precision is not required for secondary school practicals.
Digital or non-contact varieties of thermometers are recommended in place of the clinical mercury thermometers.
Other alternatives are data-logger style temperature probes or sensors.
ASTA, Science ASSIST. 2015. Mercury Spills. Science ASSIST website. http://assist.asta.edu.au/question/2706/mercury-spills