2011 CWAM Grant Recipient

University of Colorado Museum of Natural History, Zoology Section

Mariko Kageyama, Collections Manager for Vertebrate Zoology

In May 2011, the University of Colorado Museum of Natural History's Zoology Section was awarded a CWAM grant in the amount of $500. Upgrading the fluid-preserved zoology collection by the introduction of a purified water system is the title of our 2-year grant project. In conjunction with a conservation project grant we concurrently received from the Greenwood Fund of the Denver Foundation, we were able to purchase and install in our lab a compact water purification system that was deemed best suited for our specific application in the preservation of over 30,000 lots (=jars) of wet zoological specimens including reptiles, amphibians, mollusks, fish, and mammals housed at the CU Museum.

The management of fluid-preserved collections poses a unique set of challenges in many respects, as you need to monitor not only climatic factors such as light, temperature and relatively humidity at the room and storage unit level, but also control and monitor the fluid condition in order to achieve the preservation goal of the collections. Roughly two thirds of the catalogued vertebrate and invertebrate specimens in our collection are stored in fluid, either 70-80 % ethanol, 50% isopropanol, or other known types of chemicals. These standard solutions are prepared by diluting the original concentrated alcohol with water in the lab. The final preservative solutions that come in direct contact with specimens, labels, and containers, in addition to various molecules, minerals, and free ion present in the fluid, all come into play as chemical variables that affect the long-term preservation of the material. Organic and inorganic molecules include protein, lipid, and pigments exuded from the animal bodies and dissolved into fluid, as well as a trace amount of formaldehyde as is normally introduced to carcasses for an initial fixation treatment. In essence, whatever substances may end up introduced to a closed equilibrium system, they would stay and create heterogeneous and complex microenvironment at each container level, and can potentially cause an irreversible effect on the specimens being preserved.

Until a new water purification system was purchased, tap water from faucets was the only accessible supply of H2O in our building to prepare alcohol preservative. Although campus tap water is supposed to be safe enough for human consumption according to the university's Environmental Health and Safety department, previous lab results for a campus water sample indicated a detectable amount of foreign elements such as calcium, iron, copper, fluoride and nitrate. These residual contaminants in water, even though insignificant in amount, may contribute to an undesirable chemical reaction in fluid such as salt precipitation or change in acidity. Therefore, the best practice is to use purified water free from chemical contaminants in preparing preservative. After careful research and comparison among various lab water solutions, we decided to purchase a wall-mountable ion-exchange water purification system that can produce deionized water on demand out of regular feed water. Its compact unit size takes less space than typical water boilers for distillation, its capability to produce sufficient quality and amount of fresh water at a reasonable speed at room temperature on demand, and the ease and convenience of maintaining and replacing ion exchange filtration columns, made us choose this particular product. We installed the system in our lab in late May 2011 with the assistance of professional carpenters from the campus Facilities Management.

The wet collection rehousing work primarily involved transitioning the specimens gradually from degraded, weakened, or acidified alcohol to contaminant-free preservative made with purified water. It was also a good opportunity to switch old and deteriorated food-canning containers with poor sealing made of rusty metal lids to museum-quality flint glass jars closed with polypropylene screw-on lids. Our museum budget has covered the cost for purchasing new alcohol and new glass containers in order to fully implement the conservation upgrade for the entire wet collection. Reducing the stress of the overcrowded specimens in each jar has also been our focused effort. We placed priority on the herpetological and ichthyological collections in 2011 and 2012, and with the help of dedicated student assistants and a volunteer, thus far an estimated 200 gallons of 70% ethanol containing an equivalent of 60 gallons of purified water generated through the new water system was integrated into the collections.

We are really thankful to the generosity of CWAM in supporting this project, which allowed us to provide a new effective solution to improve our wet natural history collection stored today in chemically more stable fluid. The project will continue until eventually the entire wet collections undergo staged transition to cleaner fluid, one container at a time. We are committed to making significant progress over the next few years. Anyone who is interested in introducing purified water to your collection conservation project or fluid-preserved collection on a smaller scale is welcome to contact us for further information and discussion.

Click to see pictures of project 

Contact: Mariko Kageyama, Collections Manager for Vertebrate Zoology, 303-492-0160, mariko.kageyama@colorado.edu