We are concerned about exposure to some of our specimens preserved in formaldehyde. Do we have to discard them?
You may have biological specimens on your premises that are preserved in formaldehyde. You are justly concerned about exposing yourself and your students to the material, yet you do not want to discard the expensive animals. It is possible to displace the present formaldehyde solution with a substitute liquid.
Your specimens were probably packaged in a large container, e.g., jar, bucket, pail, etc. Your first step is to acquire a quantity of formaldehyde substitute material sufficient to replace the volume of liquid in your jar or bucket. Flinn Scientific sells a formaldehyde substitute known as "Formalternate" (Flinn Catalog No. F0056). Formalternate contains no formaldehyde!
Formalternate is a concentrated solution. The instructions accompanying each bottle will direct you to dilute the concentrate by a ratio of 9 parts water to 1 part Formalternate concentrate.
Once the substitute material has been acquired, you are ready to displace the formaldehyde in your jar or bucket. The room in which this process is undertaken should be generously ventilated. Place the jar or bucket in a large sink. Attach a length of tubing to the cold water outlet and, wearing gloves, force the exit end of the tubing into the very bottom of the bucket. We suggest you do this by taping the exit end of the tubing to a long stick and slowly working the stick to the bottom of the container.
Turn the water on very slowly. You may want to start the water flowing before you force the tubing into the bucket to better gauge and control the water flow. A very slow, but steady, flow is desirable.
Allow the water to flow into the bottom of the vessel forcing the formaldehyde preservative to overflow into the sink. Continue overnight or for a period of 10-12 hours.
After the washing cycle is complete, turn off the water, remove the stick and tubing, and drain all the remaining water from the container. Now replace the water with the formaldehyde substitute you acquired earlier.
No, you will not have washed every vestige of formaldehyde from your specimen, but you have removed a great deal of it. When an animal or specimen is opened as part of the dissection process, the residual formaldehyde will still be evident. However, your risk has been drastically reduced. We strongly suggest that you ventilate the room, wear gloves, and continue to implement prudent laboratory practices.
If you are still concerned about the presence of formaldehyde, simply elect to discard any formaldehyde preserved materials and start with new, non-formaldehyde preserved specimens.
Let's now address the issue of museum jars or other display jars. We suggest you do not replace the formaldehyde liquid in such jars. Despite claims to the contrary, the formaldehyde substitutes will not preserve the display animals for decades and decades as is the case with formaldehyde.
To protect against formaldehyde evaporation from these kinds of containers, acquire some paraffin wax, (Flinn Catalog No. P0003). You can also buy this kind of wax at your local grocery store. It is used to seal home prepared canned goods.
To seal your container, melt enough wax in a melting vessel to enable you to completely immerse the cap or closure portion of your museum jars. Allow the hot wax to thoroughly surround the cap of the museum jar. This wax will give you a seal that will last for years and years.
If you have further questions about formaldehyde substitutes, please call or write our technical services department at (800) 452-1261. We will be glad to assist you in any way we can