(115q) The Permeation of Mercury Vapor through Various Materials

As the world looks for more energy efficient ways of lighting, Compact Fluorecent Lightbulbs (CFLs) have become an increasingly popular alternative to the incandescent light bulb. CFLs contain an inert gas (typically argon) mixed with a small amount of mercury, and when electric current passes through the gas, ultraviolet light is emitted. The UV light then excites a phosphor coating on the inside of the glass tubing of the light bulb, causing it to emit light. CFLs last about 10 times as long as the common incandescent light bulb, and consume about 75% less energy. CFLs also produce 75% less heat than the common light bulb and can save a common household about $30 per light bulb in energy costs. The incandescent light bulb will begin to be phased out by the government beginning in 2012.

The average fluorescent light bulb contains 3-5 mg of elementary mercury. This presents itself as a disadvantage as mercury vapor released from a broken bulb can enter the human blood stream. Elemental mercury can cause various symptoms including: loss of vision, coughing, dyspnea, chest pains, rashes, weight loss, continuous tremors, erethism, gingivitis, and deafness. As a result of these health effects, the federal Occupational Health and Safety Administration's (OSHA) Permissible Exposure Limit (PEL) to mercury vapor is recommended at 100 ug/m3. Other organizations, such as the American Conference of Governmental and Industrial Hygienists recommend 25 ug/m3, and the Agency for Toxic Substances and Disease Registry (ATSDR) recommend PELs of .2 ug/m3 as a safe exposure limit for children. If released into the environment, elemental mercury can take on a more toxic form of methylmercury which can contaminate fish as well.

Three percent of CFLs are being recycled today, and many more technologies are being developed in order to help recycle products containing mercury. In order to prevent the release of mercury into the environment due to health and occupational hazards, new methods of containing mercury are being developed. Johnson et al have developed a novel nano-Se sorbent that is able to absorb and contain mercury. This allows for better handling of small amounts of mercury release (e.g. from a broken CFL). Waste Management has developed a box return recycling system which involves a consumer storing broken light bulbs in a card board box containing a metal coated bag, and mailing the box to be recycled. Ikea, Home Depot, and Wal-mart have taken recycling initiatives by starting recycling programs at stores.

However, even as various methods to develop better mercury containment are developed, there is still no published report on the permeability of mercury vapor through materials. Federal regulations recommend cleaning up a CFL bulb breakage by placing bulb debris into a double layered plastic bag. The Maine Department of Environmental Protection, however, reports that double layer plastic bags show signs of mercury vapor permeation, and recommend using glass jars for CFL bulb clean up. The goal of this study is to (i) study the permeability of various standard materials to see how well each can contain mercury vapor, (ii) to see which common house hold materials (e.g. Ziploc ® bags, garbage bags) can prevent the permeation of mercury vapor into the outside environment, and (iii) see which of these containers can prevent mercury vapor release in the long run. This study is intended to be a source for better recycling and disposal methods of mercury vapor releasing products.