The toxic underbelly of green lightbulbs

Want to reduce energy consumption and expense? Change your light bulbs-all of them. Increasing numbers of households, campuses, and businesses are reducing their energy consumption by replacing incandescent bulbs with compact fluorescent light [CFL] bulbs. It's an easy, inexpensive way for the average American to be "green." CFLs can pretty much replace any incandescent bulb, as long as people keep in mind that they usually can't replace dimming lights. But what most people might not know is that when they break they can be toxic, because they contain small amounts of mercury (Hg).  This why CLF disposal should follow a few rules:

1) dispose of them in recycling facilities specially equipped to deal with CFLs

2) when they break, you should open a window and make sure a vacuum isn't used around the area for a while.

3) throw away bedding or clothing that has come into contact with the powder from the broken bulb

Wait a minute, this is getting complicated. Where is the nearest CFL disposal facility? In fact, Home Depot has the nation's most widespread recycling program for CFLs in the US⁽¹⁾. Without something comparable to Europe's WEEE legislation that requires corporations to be responsible for disposal costs and labor, the US must completely rely on corporate resources for now.

My school's campus is full of energy and water saving features, and while I trust my school to maximize "green" projects in buildings, unfortunately I can't say the same for my fellow students. High-achieving young men and women though they may be, they are still college students who have a hard enough time getting out of bed in time for class. Would every single one of them carry through with proper CFL disposal, especially considering how often light bulbs break in rowdy college dorms?  Since I started off my summer working as a student porter cleaning out dorm rooms after the big summer move-out, my empirical research says,  um...no.

Ok, so a few bulbs break. Minute amounts of inorganic mercury leak out. What's the big deal?

Well, inorganic mercury, the kind found in a freshly broken CFL, is itself not that harmful. Problems arise when this inorganic mercury, through various interactions with the surrounding environment and microorganisms, turns organic.  The addition of one or two seemingly innocent methyl groups to mercury converts mercury into its organic forms, methyl and dimethyl mercury, that are dangerous because they can cross the blood-brain barrier. Put simply, they're neurotoxins that can permanently derail brain and body functions, and even kill you at high enough doses. A not-so-comforting study^{(2, 3)} found that various landfills in Florida released into the air both dimethyl mercury and methyl mercury in amounts significantly above background levels.  Something many people tend to forget is that, even though it's a metal, mercury is volatile enough that it's possible to get mercury poisoning just by breathing it in.

Finally, methyl and dimethyl mercury also have the rather sinister ability to bioaccumulate, which means they don't degrade and instead build up in muscle tissue over time. On top of that, this mercury can biomagnify, meaning this bioaccumulation is carried up through the food chain. Eventually, these originally small amounts add up exponentially to hazardous levels over only a few years. Things become disastrous when these tiny amounts end up in our food⁽⁴⁾ or water⁽⁵⁾ supply, which can happen through seepage into groundwater⁽⁶⁾. One study⁽⁷⁾ reported that things get even worse from there: mercury actually becomes more mobile in the presence of landfill effluent, i.e. trash-juice.

Does this news about mercury mean we should give up CFLs? Absolutely not—they are doing what we hoped they would, which is reduce greenhouse gas emissions by using less energy. They also have the added bonus of lasting much longer than incandescent bulbs. At the moment, many CFL manufacturers are cutting down on the amount of mercury used, so that's at least one small improvement. But even smaller amounts will add up in landfills and watersheds, so as a "green" alternative, they contribute more toxic waste than they should.

Similarly, we should be cautious with other well-intentioned "green" efforts. As with many other movements that are picked up by the larger public, the potential for unforeseen consequences tragically rises to Murphy's Law-esque levels. The policies that regulate them matter as much as the care individuals put in when using them.

1. Rosenbloom, Stephanie. "Home Depot Offers Recycling for Compact Florescent Bulbs." New York Times, June 24, 2008, Business section. 

2. Lindberg, S.E., Wallscläger, D., Prestbo, E.M., Bloom, N.S., Price J., D. Reinhart. Methylated mercury species in municipal waste landfill gas sampled in Florida, USA. Atmospheric Environment 35, issue 23 (August 2001) 4011-4015. 

3 Lindberg, S.E., Southworth, G., Prestbo E.M., Wallscläger, D.,Bogle, M.A., J. Price. Gaseous methyl- and inorganic mercury in landfill gas from landfills in Florida, Minnesota, Delaware, and California. Atmospheric Environment 39, issue 2 (January 2005) 249-258.

4. Turtle Island Restoration Network, Mercury Calculator. Calculate how much mercury you're eating!

5. Environmental Health Department, Ministry of the Environment, Government of Japan. "Minamata Disease The History and Measures." 2002.

6. Stephans, Tim. "Groundwater Fingered as a Source of Methylmercury in Coastal Waters." UC Santa Cruz. June 8, 2009, Press Releases. 

7. Niebla, E.E., Korte, N.E., Alesh, B.A., W.H. Fuller. Effect of municipal landfill leachate on mercury movement through soils. Water, Air, & Soil Pollution 5, issue 4 (June 1976) 399. 

Other resources:

Check out Europe's WEEE bill!

Zerowaste has a summary of findings about mercury in landfills, and a good description of what happens at a proper CFL recycling facility.

Where to go to dispose of CFLs? Look it up at the EPA! 

For even more information, the EPA has a thorough FAQ about CFLs as well.

Illustration by Justine Chow.