Environmental Release of Mercury from Broken Compact Fluorescent Lamps

Abstract

This article presents an original study on the releases of mercury (Hg) from broken compact fluorescent lamps (CFLs) under various environmental conditions. Leaching of Hg in liquids was examined using the U.S. Environmental Protection Agency's standard procedures Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure. Emission of Hg in vapor phase from broken CFLs was detected using an emission monitoring system. CFLs of eight different brands and four different wattages were tested. Results show that Hg contents in CFLs varied significantly with brand. Total amount of Hg contained in each CFL ranged from 0.1 to 3.6 mg, and only <4% of the Hg was TCLP-leachable. Hg concentrations in TCLP extracts of all the new CFLs tested were lower than the regulatory level of 0.2 mg/L and thus the discarded CFLs do not fall into the hazardous waste category. Hg concentrations in Synthetic Precipitation Leaching Procedure extracts were lower than those in the TCLP extracts. Hg vapor emission test revealed that the CFLs continuously release Hg vapor once broken and the release can last over 10 weeks. Total amount of Hg vapor released from a broken CFL can exceeds 1.0 mg, which can cause Hg level in a regular room to exceed the safe human exposure limit under poor ventilation conditions. Results provide useful implications in guiding the handling and treatment of CFLs during and after use.