Determination of Total Metallic Mercury in Compact Fluorescent Lamps (CFLs)

The United States Environmental Protection Agency/Environmental Response Team (US EPA/ERT), in conjunction with St. John's College, Dr B R Ambedkar University, Agra, India, is conducting a study to determine mercury vapor emission rates resulting from broken compact fluorescent lamps (CFLs) in a residential setting. The overall objectives of the study are to obtain a mercury emission model and provide a homeowner with cleanup procedures and disposal options for broken CFLs. An important component in achieving these objectives is the determination of the total mercury content in CFLs for the selection of bulbs to be used in the emission study. Most of the currently available CFLs in the United States (U.S.) market are manufactured in China for U.S. companies. Several different types of CFLs were purchased from local stores and the cap and electronic parts were removed without breaking the bulb. The bulb was then placed into a 2-L polypropylene bottle containing glass stoppers or glass marbles in a mixture of nitric acid and bromine monochloride solution (BrCl). The mixture was shaken to break the lamp and allow the mercury to be completely absorbed by the BrCl. The digested samples were analyzed for mercury using standard cold vapor atomic absorption (CVAA) methods. This CFL preparation method provides excellent results for laboratory control samples (typically, 90%-110% recovery) and good repeatability for CFL bulb analyses. The sampling and analysis phases of this study are discussed in this paper.