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Candles sold in Australia have
been found to have lead wicks which when burnt can cause lead poisoning or even death.
Adelaide lead assessor, Mike van Alphen found that these candles, all imported from China
could release 500 to 1000 micrograms of lead per hour into the air (up to tested candles
finding some with wick cores of lead wire and others with lead tin and zinc. The lead wick
candles were capable of transferring some into the air for outdoor air quality is 1.5
micrograms of lead per cubic metre of air.
Intensive testing and risk
assessment by Lead Sense has identified a consumer product that has a high
probability of producing moderate to severe lead poisoning.
The particular* items tested
are a 38 cm tall candle having a wick that contains a central wire that is composed of
lead (Pb). There are many related candle products having metal wick cores that may or may
not present a hazard; the full range of candles has not been tested. Some candles have
been found to have wick cores of lead-tin (Pb-Sn) alloy and Zinc (Zn). All candles seen
with metal and lead wick cores have been made in China.
The candles* tested were
capable
The candles tested can burn for
over 100 hours and emit over 100,000 micrograms of biologically available, sub-micron size
Pb particulate into the air.
Modelling of a number of
residential scenarios and detailed exposure assessments readily demonstrate that daily
candle* burning of several hours duration would result in elevated blood lead levels. The
burning of multiple candles in a confined space for greater than 3-6 hours daily would
readily result in severe Pb poisoning.
Particular concern exists in
households where candles are used as a long term source of lighting. This of course is
readily the case in developing countries and can be the case in the homes of the very
poor.
Long-term use of these candles*
would result also in the contamination of carpets and soft furnishings in houses by fine
particulate Pb. While the short-term high exposure risks are via inhalation, longer term,
child lead exposure will be due to high lead-in-dust loadings on surfaces that children
come into contact with.
Recommendations For
the Public
1) Do not use candles*
containing Pb wick cores and in the short term be suspicious of any candle containing a
metal wick core.
2) Authorities should recall
all candles known to have a Pb wick cores, and suspend sales or ban the sales of all
candles having metal wick cores (unless determined to be safe).
3) If you have recently
burnt such candles* for greater than an hour per day or for longer than 5 hours and have
young children or pregnant women in your household; consider going to your GP for a
referral for a blood lead test.
4) If burning of such candles
has been extensive and there is in addition evidence of elevated blood lead levels it will
be important to ensure that accumulations of Pb in house dusts do not continue to Pb
poison children (particularly less than 3-4 years old) in the house due to normal child
hand-to-mouth activity.
Advice from public health or
environmental health professionals may be required. Specialists in Pb exposure
investigation and Pb testing such as Lead Sense will be able to conduct detailed
investigations if and when required.
Particular Investigations
Carried Out by Lead Sense to Date
Detailed testing has been
carried out, this work has been accepted for publication in an international scientific
journal.
The work involved has included:
- design and building of a
stainless steel combustion/testing chamber
- sampling of emissions from 38cm
candles
- testing wick cores by SEM/EDS to
check for the presence of elements other than Pb
- evaluation of the total amount
of Pb per unit length of wick core
- analysis of chamber emission
filters by AAS for Pb to determine air Pb emission rates
- analysis of chamber emission
filters by XRD to demonstrate that the Pb compounds emitted are of a highly bioavailable
form
- investigation of emission
particles by FESEM to demonstrate that deposition of particles in the lung is likely to
occur due to particle size
- calculation of the candle Pb
emission rate
- calculation of the proportion of
Pb wick core emitted to air
- modeling of the air Pb
concentrations over time under different candle burning, room volume and ventilation
scenarios
- calculation by two methods of
likely child Pb uptake or child blood lead levels (PbB) based on a range of human exposure
factors and known associations with Pb in air and Pb exposure.
- FESEM Field Emission Scanning
Electron Microscope
- SEM/EDS Energy Dispersive
Analysis in a Scanning Electron Microscope
- XRD X ray Diffraction
- AAS Atomic Absorption
Spectroscopy
- PbB Blood Lead Level
As you may appreciate, this
work, funded and carried out by Lead Sense has been both time consuming and has
incurred modest expenses.
Further Investigations
Recommended ( More Information Required )
Given appropriate funding and
support there are a number of additional matters that could be readily investigated by Lead
Sense.
1) Is there a population of Pb
poisoned people that can be identified and prioritised as a result of use of these candles
with a view to conducting cleanups of residential settings and eliminate ongoing Pb
hazard.
2) There are a range of candles
having metal core wicks that may pose hazards due to the toxicity of other heavy metals
and more wide ranging investigation may be warranted.
3) There is a need to evaluate
the proportion of Pb fallout INDOORS related to the use of these candles so as to
determine the extent of "long-term" house contamination by the combustion of
candles with Pb core wicks.
Such further investigations are
important. Lead Sense is the best placed consultancy in Australia to respond to and manage
such investigations.
Lead Sense has the capacity to
investigate consumer products using a wide range of analytical techniques and conducts
evaluations of human exposure, indoor air quality and environmental contamination. An
associated business is Environmental Contaminant Investigation.
What to Look For in Candles
The candles having a metal wick
core come in such a vide variety of colours, shapes and containers that it is likely to be
pointless at this stage to focus on the general size, shape, colour etc and other
‘external’ characteristics so as to identify problematic candles. These candles
are unbranded and are poorly labelled as to ‘origin’ or manufacturer. They can
be found in chain-stores specialising in the sale of low-cost items from China.
You need to examine the wick
of the candle.
If you can see a silvery or
dark metallic core to the fabric of the wick then you have a candle that you should be
suspicious of. This is of course easy to do if the candle is new. Some of the metallic
wick cores are solid metal 0.4 mm diameter and some metal cores are up to 0.8 mm diameter
with a central hole in the core resembling electrical solder wire.
If the candle has been burning
and you have noticed silvery droplets at the wick tip, and silvery metallic droplets at
the base of the molten wax pool this is another sign of metal wick cores.
If you take a pin and scratch
into the tip of a charred burnt wick you should ‘feel’ the metallic core of the
candle. [Mike also said that using a needle to separate the strands of the wick of a new
candle will readily reveal the metal core.]
Further Information
For further information such as
graphics or photographs, please call Mike van Alphen at +61 8 8241 7055. If Lead Sense
or Environmental Contaminant Investigation can assist you with consumer product testing,
human exposure or environmental test work projects please get in touch.
Mike
van Alphen
Lead Sense
PO Box 242
Hindmarsh SA 5007
AUSTRALIA
Phone +61 8 8241 7055 ###
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