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 University of Michigan School of Public Health study
of candles purchased from stores in southeast Michigan shows
that some candles on the market today are made with wicks that
have either lead or lead cores that emit potentially dangerous
levels of lead into the air.
 The
study is by Jerome Nriagu, a professor of environmental health
sciences, who examined lead emissions from 15 different brands
of candles made in the United States, Mexico and China. He also
examined the concentration levels of lead that lingered in the
air in an enclosed space, such as a room measuring 12 feet by
12 feet and 10 feet high, after one hour and then again for five
hours.
Nriagu's study
showed that lead emission rates for the candles ranged between
0.5 and 327 micrograms per hour. After burning the candle for
one hour, the lead levels in the air of an enclosed space were
estimated to range from 0.04 to 13.1 micrograms per cubic meter,
which compares to the US Environmental Protection Agency recommendation
of 1.5 micrograms per cubic meter for ambient air. After one
hour, five of the candles Nriagu tested emitted unsafe levels
of lead into the air that measured greater than 1.5 micrograms
per cubic meter.
After five
hours, the lead levels in an enclosed space ranged from an estimated
0.21 to 65.3 micrograms per cubic meter. Candles produced in
China and the United States released the highest levels of lead
into the air. Regular exposure to lead in this manner in confined
spaces could pose health risks to people with weak immune systems,
especially children and the elderly, Nriagu said.
"Lead
poisoning remains one of the most serious environmental health
diseases in this country and other parts of the world. It affects
many organ systems and biochemical processes with the most serious
sequelae often occurring in the central nervous, cardiovascular
and blood systems," Nriagu said.
Nriagu's findings
are consistent with an Australian study due to be published in
the journal Science of the Total Environment. In that
study, Mike van Alphen of Lead Sense, an independent consultancy
in Australia involved in environmental lead testing, lead exposure
investigations and consumer product testing, examined a single
brand of candle sold in Australia. The candle he examined released
up to 1,130 micrograms of lead per hour.
Studies have
shown that the central nervous system of children is particularly
sensitive to lead. Some of the most damaging neuropsychological
effects of lead poisoning of young children include learning
disabilities, reduced psychometric intelligence and behavioral
disorders. These effects have been associated with chronic low-level
exposure to lead and are believed to be irreversible.
Not all candles
are made with wicks that have metallic cores. The practice is
primarily used with candles that are needed to burn longer, such
as scented or ceremonial candles. A metal core is used to provide
rigidity to the wick, which provides an even and slower burn
rate, and to reduce the mushrooming at the tip. Since lead and
its alloys melt at relatively low temperature, a large fraction
of the wick core material is volatilized as the candle is burned.
"Because
it is costly and difficult to control lead once it is released
to the environment and medical treatment does not fully reverse
the health effects, the optimal strategy for minimizing the risk
involves the reduction or elimination of exposure in various
forms. This study shows that there are still other important
domestic sources of lead exposure that have escaped public scrutiny
and legislative control. Leaded candles were recently banned
in Australia, and we recommend a similar action in this country,"
Nriagu said. 
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