Exposure analysis of accidental release of mercury from compact fluorescent lamps (CFLs).

Mercury release after breakage of compact fluorescent lamps (CFLs) has recently become an issue of public health concern, especially in the case of early life infants. Preliminary, screening type calculations have indicated that there is potential for increased intake of mercury vapor by inhalation after breakage of a CFL. Several experimental and computational studies have shown that, when modeling the breakage of a CFL, the room space must be segregated into different zones, according to the potential of mercury vapor to accumulate in them after accidental release. In this study, a detailed two-zone model that captures the physicochemical processes that govern mercury vapor formation and dispersion in the indoor environment was developed. The mercury fate model was coupled to a population exposure model that accounts for age and gender-related differences in time-activity patterns, as well as country differences in body weight and age distribution. The parameters above are used to determine the intake through inhalation (gas phase and particles) and non-dietary ingestion (settled dust) for each age, gender group and ethnicity. Results showed that the critical period for intake covers the first 4h after the CFL breaks and that room air temperature significantly affects the intake rate. Indoor air concentration of mercury vapor may exceed toxicological thresholds of concern such as the acute Reference Exposure Limit (REL) for mercury vapor set by the Environmental Protection Agency of California. Ingestion intake through hand-to-mouth behavior is significant for infants and toddlers, counting for about 20% of the overall intake. Simple risk reduction measures including increased indoor ventilation followed by careful clean-up of the accident site, may limit dramatically the estimated health risk.