El mercurio en las bombillas de bajo consumo
3. Do mercury emissions due to light bulb use and disposal pose a risk to the environment?
- 3.1 How much mercury is released by different light bulbs during use and disposal?
- 3.2 How much mercury is released into the environment from other sources?
- 3.3 Do mercury releases from light bulbs pose a risk to the environment?
3.1 How much mercury is released by different light bulbs during use and disposal?
Several types of light bulbs contain
mercury. These include
compact fluorescent lamps, straight
fluorescent tubes, as well as other lamps such as high-pressure sodium lamps.
However, at present there is not sufficient information on how many lamps of each
type are sold, how long they last and how they are disposed of, so it is not
possible to fully assess the risk that their use poses to the environment.
In 2007, approximately 4% of the total electricity consumption in the EU-27
was used to provide power to light bulbs (excluding spot lights) and three
quarters of this electricity is used in homes. In 2007, the best-selling lamps in
Europe were frosted incandescent bulbs. Compact
fluorescent lamps sold half as much as these, closely followed by clear
Power generation based on coal implies emissions of
mercury to air. [According to the DG Joint
Research Centre, the generation of 1 kWh emits 0.016 mg of mercury to
air, assuming that 31 % of the electricity used in the EU comes from
coal.] Therefore, using any type of light bulb contributes indirectly to mercury
emissions, even if the lamp itself does not contain mercury. To assess the
contribution of each type of lamp to the total amount of mercury released, it is
necessary to add the mercury emissions associated with energy production for their
use to the amount of mercury that reaches the environment when the lamp breaks.
Of the lamps investigated, incandescent
lamps result in the highest emissions of
mercury to the environment per unit of
light produced, and halogen lamps the least per unit of light produced.
Compact fluorescent lamps lie somewhere
in between. This calculation is based on the assumption that only 20% of the lamps
would be recycled at the end of their useful life. In this case, three quarters of
the overall mercury release by CFLs would
occur at the end of the lamps’ lifetime when the CFL is not disposed of
appropriately, i.e. thrown with unsorted household waste and not recycled.
Overall, for the light bulbs sold in 2007 over 5000 kg of mercury would be
released to the environment in the EU as a result of light bulb usage and
3.2 How much mercury is released into the environment from other sources?
Worldwide, an estimated 3400 to 5300 tonnes of
mercury are released into the environment
each year. 1400 to 2300 tonnes are due to natural events (e.g. volcanic activity,
weathering of rocks) but the remaining 2000 to 3000 tons of emissions are the
result of human activity.
Mercury is released into the soil, water
and atmosphere, but most of the human emissions are to the soil, mainly due to
An important use of mercury is in
dental amalgams used for tooth fillings.
Some of this mercury finds its way into the environment through wastewater
discharges from dental practices and through the leaching of mercury from the
teeth of deceased people.
3.3 Do mercury releases from light bulbs pose a risk to the environment?
The mercury emissions due to the use and
disposal of household lamps (incandescent, halogen & CFLs combined) are
approximately 20 times lower than those from dental practices and represent a tiny
proportion of the overall mercury released from all human activities so they are
considered very unlikely to pose any risk to the environment. However, sites that
collect and dispose of light bulbs could be a local risk if they do not deal with
potential mercury releases appropriately.