Mercury exposure from compact fluorescent lights

September 27, 2011

A commenter on a previous post asked about potential mercury exposure from broken compact fluorescent lights (CFLs). There are also various stories floating around the internet (such as this one) about the dangers of mercury in CFLs. So I thought I’d take the opportunity to look at how much mercury someone could be exposed to from a broken CFL, and whether there were any risks from that level of exposure.

A CFL typically contains about 4 mg of mercury (according to US EPA); a lot of newer CFLs contain 1 mg or less. I’ll look at the worst-case exposure, so let’s go with 4 mg of mercury in a bulb. In reality that mercury isn’t going to all be in the air right away – the evaporation rate of mercury is about 56 micrograms per hour per square centimetre – but figuring out the rate at which it enters the air requires assumptions about the area covered by the spilled mercury, temperature, pressure, etc. To keep things simple and to make sure I’m considering the absolute worst case, I’ll assume that all of that mercury instantly volatilizes.

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Phthalates in children’s toys

January 18, 2011

The Government of Canada has just announced new legislation that will significantly restrict the levels of six phthalates in children’s toys and child care products. Europe imposed similar restrictions several years ago, and the US in 2009. Today I’ll briefly look at why these restrictions are in place, why they only apply to toys and child care products, and what it all means.

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Canada declares BPA toxic

October 13, 2010

Canada has now officially declared BPA (bisphenol A) to be toxic. But what does that mean? Is it going to be banned? The short answer is, probably not.

As I have discussed previously, when the Canadian government declares something to be toxic, it has a fairly specific legal definition. It means that either it may be having adverse effects on the environment or biological diversity, it may pose a danger to the environment on which life depends, or it may constitute a danger to human health.

In the case of BPA, it was declared toxic for 2 reasons. The primary reason was actually related to the environment, and specifically BPA in sewage effluent affecting aquatic organisms. The second reason was that, even though Health Canada concluded that exposures were below levels known to cause harm, the margin of safety was too small for formula-fed infants.

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