American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California. Fairfax, VA: American Industrial Hygiene Association, 2002 Jun; :31
During the past two centuries, millions of botanical specimens in museum and university study collections were treated with mercuric chloride as a prophylactic against mold and insect pests. Over time, mercuric chloride disassociates into elemental mercury vapor, accumulating in closed storage. Collections facilities typically have hundreds of cases, each posing a potential health hazard to staff and visiting scientists. Practical and affordable means for mercury vapor detection and mitigation were explored. A commercially available mercury indicator powder was mixed into a water slurry, applied to glass slides, and placed inside multiple cases. Ambient concentrations inside the cases were measured at time intervals with a direct measurement instrument and confirmed to correspond to varying degrees of indicator color changes (verified by Munsell color charts). The indicator slurry application provided a quick, inexpensive qualitative detection method for mercury vapor, even at extremely low levels (0.003-0.005 mg/M3). Next, the efficacy of case aeration as a prudent work practice was examined. A random direct measurement sampling of 184 collections cases was conducted within 6 inches of the front of the open case, at 15, 30, 45, and 60 second intervals per case. Comparison of the arithmetic means of each interval's sample set revealed their statistical distinction. In the presence of good general ventilation, a true and significant reduction of mercury vapor concentration (to less than 0.025 mg/M3) was achieved by sixty second case purging. Finally, a scavenger product in commercial development (paper sheets coated with a treated char- coal mixture) was tested in a random sample of collection cases. Preliminary results indicated that the product was effective in reducing accumulated mercury vapor concentrations, with the potential as an affordable and easily applied product.
American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California