(SV*)null
interpreting the void as SamV
According to various sources cited by Wikipedia, Mercury in fluorescent bulbs is in elemental form, at a negative pressure (ie, close to vacuum). Otherwise, the bulb wouldn't work.
As the bulb gets old, the mercury starts to stick to the side of the glass, presumably bonding with something in the phosphorescent coating. Eventually, the mercury runs out and the bulb takes a while to start, flickering. When the mercury is fully gone the bulb will glow a different colour, such as pink if the base gas is argon.
The level of Mercury emitted per bulb is small, but only if the bulb is old and the amount of mercury that was put in the bulb was closely matched to the length of life of the phosphor (the element in the fluoro) - according to the EPA. Actually, their figure assumes a very low mercury content bulb.
The bad news is that elemental mercury in the environment is converted by bacteria into methyl mercury. And it raises the immediate question about whether in a landfill it matters that the mercury is fused to the glass - it may eventually be converted to methyl mercury and concentrate in river-life anyway. On the other hand, with NZ's size it's entirely possible that natural mercury sources This makes a strong case for thoughtful disposal of CFLs. This might make the plans to ban incandescents look like a waste of resources, but I wouldn't go that far until seeing how much the cost of recycling adds onto the lifetime cost, especially in a post-ETS world where the carbon cost of marginal power use must be considered.
I think that this calls for Mercury Credits - people that refine and extract mercury from sealife (eg, fish oil manufacturers) or otherwise scrub it can sell it back to those using mercury in their products for big bucks. This is just one reason I like Kyoto and the ETS - it provides a handy framework to hang minor pollutants like this off, to recycle emissions of all forms.
Speaking of ETS and CFLs, I noticed a message on the side of a recently purchased bulb:
Upon purchasing this bulb you agree that the CO₂ credits it generates belong to [the manufacturer]
What? This device consumes power, but somehow it creates Carbon credits? So, if I go and buy 1,000 bulbs and rig them into a big display, I've just saved the world?