Wednesday, February 8, 2012

Mercury in compact fluorescent light bulbs: A cause for concern?

It's no surprise the compact fluorescent light bulbs, or CFL's, have become widely used.  Compared to a traditional incandescent bulb, a CFL requires about a quarter of the energy and lasts up to 10 times longer, which saves money and energy.  However, the contents of the CFL have caused concern among customers. 

On average, a CFL is likely to contain 4 milligrams of mercury.  Mercury, which was once present in household thermometers (that contained about 15 milligrams of mercury), is known to have detrimental effects on the nervous system, especially in children and developing fetuses.  With this potentially harmful chemical being contained by nothing but some fragile, glass tubing, legitimate concerns about the safety of CFL's have emerged.

One major source of unease is the disposal of the bulbs.  When they break in a landfill, will mercury seep into soil or water sources, or will it evaporate into the air? 

Of course, keeping mercury out of natural spaces is important.  If mercury, specifically in the form of methylmercury, enters certain ecosystems, it gets passed up the food chain through a process known as biomagnification.

Many lakes in the U.S. contain fish with staggering levels of mercury. 
source: U.S. Geological Survey

Surprisingly, using CFL's will theoretically reduce the amount of mercury to enter these natural spaces.  As mentioned previously, CFL's use about a quarter of the energy that incandescent bulbs use.  The energy to power the bulbs is likely coming from a coal plant.  Coal naturally contains traces of mercury, and when the coal is burned, the mercury is released into the atmosphere.  So, burning coal to harness energy to fuel an incandescent light bulb will emit more mercury than in the case of a CFL because the incandescent requires more energy altogether.  For this reason, Julianne Pepitone at Popular Mechanics asserts that the total mercury emission resulting from the use of an incandescent bulb will exceed that of a CFL by 4.65 milligrams (source).

So, to reduces the amount of mercury being released into the atmosphere, use CFL's.  But, be sure to dispose of them properly.  Many communities have environmental services that take care of recycling potentially hazardous waste, like CFL's.  For Meadville, ECS&R is a reliable source.  As mentioned in the Popular Mechanics article, can help readers locate such service centers.

If you still feel uncomfortable about using a mercury-containing CFL, be assured that the are attempts to reduce the amount of mercury in the bulbs.  From 2007 to 2008, the amount of mercury in bulbs dropped 20 percent (source I).  Hopefully, the trend will continue.

For reference, here are instructions to deal with a broken CFL.

Free CFL's are available for Allegheny College Students!  Contact an EcoRep for your free bulb.

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