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LEAD IN CANDLE EMISSIONS
Wasson*, S, Z Guo*, J. McBrian, AND L. O. Beach. LEAD IN CANDLE EMISSIONS. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier Science BV, Amsterdam, Netherlands, 296(1-3):159-174, (2002).
The candle-using public should be made aware that the core of candle wicks may contain lead. Used as a stiffening agent to keep the wick out of the molten wax, lead can be emitted as particulate to the air and then deposited on indoor surfaces. To define the problem, 100 sets of candles (two or more identical candies) were purchased locally. The criterion for purchase was that the candles must appear to contain a metal-cored wick or be covered by a metallic pigment. Of the candles purchased, 8% contained lead wicks. The wicks were 39 to 74% lead, and the lead cores had linear densities of 13 to 27 mg/cm. Candles were burned to completion in a closed chamber to capture the air emissions, and the candle residue was extracted to close the lead mass balance. It was found that individual candles emitted lead to the air at average rates that ranged from 100 to 1700 micrograms/hr. Assuming realistic indoor conditions, these emission rates were modeled to project room concentration, child inhalation, and indoor deposition scenarios. Results showed that burning single candles can easily raise the source room concentration above the ambient air lead concentration limit of 1.5 micrograms/m3 set by EPA. Burning multiple candles can elevate it above OSHA permissible exposure limits of 50 micrograms/m3 . Although blood lead levels have dropped precipitously in the United States since lead was phased out of gasoline in 1986, over 1 million children still have levels above 10 micrograms/dL. Considering that candle sales in the U.S. are estimated at $1 to 2 billion per year, and considering that children may spend as much as 90% of their time indoors, it is reasonable to suspect that some blood lead elevation in children arises from indoor microenvironments where lead-wicked candles are burned.