Mercury in CFL vs Fish

Posted on September 29th, 2009 by Bruce

Mercury in CFL vs Fish

We have certainly heard lots over the years about the mercury we add to our bodies by eating certain fish and seafood (Tilefish, Shark, Swordfish,Tuna). Lately, Mercury levels in CFL lights has hit the news. How do these Mercury concerns compare? Which is more dangerous?

How Much Mercury is Safe?

According to the U.S. Environmental Protection Agency (EPA), the safe upper limit of mercury consumption is about 0.1 microgram per kg of body weight per day. The U.S. Food and Drug Administration (FDA) and the World Health Organization (WHO) believe the safe dose is 3 times higher, 0.3 micrograms/kilogram/day . For someone weighing 150 pounds (68 kilograms), that’s 6.8 to 20 micrograms per day.

Mercury in Fish/Seafood

Mercury in fish, which is actually methylmercury to be specific, is a legitimate problem.

For most fish & seafood, you won’t come close to that limit if you don’t eat it every day. Small fish typically contain less mercury per gram, because they don’t live as long and ingest as much mercury. Flounder, for example, has 1.1 micrograms of methylmercury per ounce. If you ate 4 ounces of flounder every day for a week you would still be under the recommended dose. That’s not true of all fish, though.

Larger fish contain the most mercury. Check out this table from the FDA, to see how much mercury is in each species of fish.

Mercury in CFLs

A compact fluorescent light (CFL) bulb contains 2.3 milligrams to 5 milligrams of mercury. Though these levels are much higher than the mercury levels found in fish, you are not ingesting any mercury at all. Only if a CFL breaks, are you in danger of inhaling the mercury vapor and even then, your risk is very limited. If a CFL breaks, open area windows and close doors to the room if possible. If you have the room closed off and windows open, give it a few minutes for any mercury vapor to dissipated, then clean it up thoroughly with a broom, not a vacuum. Vacuums can expel the mercury into the air. Seal all the debris in a plastic bag and dispose of it at an approved site.

The roughly 4 mg of mercury found in CFLs is quite small when compared to mercury levels found in: Watch battery — up to 25 milligrams; Thermometer — up to 2 grams; Tilt thermostat — up to 3 grams.

Conclusions

As mercury exposure via CFLs depends entirely on breaking the bulb and not correctly cleaning up, fish definitely pose a greater risk when it comes to mercury poisoning. We actually eat the mercury when we eat the fish. However, paying attention to the fish species you eat, can provide a balance between the proven health benefits of eating fish and the small amount of mercury you might be ingesting.

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