Academic journal article Journal of Environmental Health

Assessing Occupational Mercury Exposures during the On-Site Processing of Spent Fluorescent Lamps

Academic journal article Journal of Environmental Health

Assessing Occupational Mercury Exposures during the On-Site Processing of Spent Fluorescent Lamps

Article excerpt

Introduction

Fluorescent lamps are an efficient, and thus commonly used, source of lighting in office buildings, retail establishments, and schools (U.S. Environmental Protection Agency [U.S. EPA] Office of Solid Waste, 1998). In order to operate efficiently, all fluorescent lamps contain some amount of mercury. Typically, fluorescent lamps consist of a sealed glass tube coated with a powdered phosphor material and filled at low pressure with argon gas and mercury vapor. Tungsten coils coated with an electron-emitting material form electrodes at either end, and when voltage is applied, electrons pass through the tube, striking the argon atoms and releasing more electrons. These electrons strike the mercury atoms, causing the orbital electrons to move to an excited state, and upon relaxation, the mercury atoms emit ultraviolet light, which strikes the phosphor, causing it to fluoresce and produce visible light (U.S. EPA, Control Technology Center, 1994).

When fluorescent lamps are discarded or recycled, and subsequently broken, mercury may be released into an occupational setting or the surrounding environment, resulting in possible adverse health or environmental effects. When mercury is released into the environment, it can be converted into organic forms such as methylmercury and can bioaccumulate through the food chain (Raposo & Roeser, 2001). All forms of mercury are toxic to humans, adversely affecting the endocrine and nervous systems (Aucott, McLinden, & Winka, 2003).

According to U.S. EPA, 881 million fluorescent lamps were projected to be discarded in 2003, and the National Electrical Manufacturers Association (NEMA) estimated that 661 million lamps were discarded in 2000 (NEMA, 2000; U.S. EPA Office of Solid Waste, 1998). While U.S. EPA and NEMA numbers for lamps disposed on an annual basis vary somewhat, the likely true number of lamps discarded is still on the order of several hundred million per year and will probably continue to increase as U.S. EPA promotes the use of fluorescent lamps for energy conservation measures. In supporting the use of fluorescent lamps through its "Green Lights Program," U.S. EPA recognized NEMA's claim that mercury released into the environment by lamp disposal is significantly offset by energy conservation since the reduction in mercury emitted from anthropogenic sources, such as coal-fired power production, would be reduced by the use of fluorescent lamps (U.S. EPA Control Technology Center, 1994).

Historically, the processing of spent lamps involved removal of the spent lamp from the light fixture and either placement in the municipal waste stream or accumulation in fiberboard boxes for possible recycling. Modifications to applicable hazardous waste regulations and demands for spaces occupied by large volumes of spent lamps combined to make the on-site processing of spent lamps a desirable alternative. While on-site processing (inclusive of spent-lamp handling, movement, crushing, and residue collection) can help prevent the introduction of mercury into the municipal waste stream, the process represents a possible source of mercury exposure to workers. This circumstance is of particular concern because on-site lamp processing is rarely carried out in facilities specifically designed for this operation. A characterization of the possible exposures inherent to these on-site operations would be useful to determine if excessive occupational exposures were possible.

Universal Waste Rule

To reduce the amount of mercury potentially released into the environment by fluorescent lamps, U.S. EPA added used mercury-containing lamps to the list of "universal wastes" on July 6, 1999 (Hazardous Waste Management System, Modification of the Hazardous Waste Program, Mercury-Containing Lamps Proposed Rule, 1994). Universal wastes are hazardous waste that are widely generated and include used batteries, pesticides, mercury-containing thermostats, and paint and paint-related wastes. …

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