Some web searching led me to suspect that the safe level of methylmercury in water is about 0.12ng/l, which gives a mercury concentration of about 0.3ppm in 3-year-old fish.
The environmentalists are again showing their dishonesty. There is obviously good mercury and bad mercury. Good mercury comes from light bulbs, and should be feed to your children to make them strong and healthy. Bad mercury comes from power plants and should be banned.
“Frankly, the public simply does not know if some of our high-risk fish are safe to eat or not,” said Ms Kedgley. “We need to take the FSANZ warning seriously and begin an urgent testing regime.
“Seven years ago the Total Diet Survey called for increased monitoring of mercury levels in fish
in New Zealand, but so far nothing has happened.
But now we need to use mercury bulbs, and in fact ban all other types, because they save us burning more coal. Oh dear.
Environmentalists also raised the alarm about CFL bulbs just last year:
But now they are onside:But environmental problems do not end with organic matter. There is growing concern about the heavy metals associated with e-waste, treated timber, batteries, CFL bulbs and the like.
Each year we spend approximately $660 million on electricity for lighting in this country, generating about 2.65 million tones of greenhouse gas emissions. New Zealanders will be able to save almost $500 million by 2020, just by changing the lights.
That ignores the heat created by bulbs which will need to be substituted when it is cold. Also, put it into perspective. The 40 GWhrs generated in NZ each year is worth about $8bn at retail, so lighting is a small part. How about investing in some serious global warming, or bring back coal burners, to try to cut heating bills?
Then there was this story in today's Herald:
Is the mercury in CFLs dangerous?
No. A current generation CFL has probably got less than five milligrams or about the size of the end of a ballpoint pen.
By comparison, a typical thermometer has between 500 and 3000mg of mercury.
That's a bit like saying it's OK to drink a car tank dry of petrol because petrol station tanks contain 200x as much.
The type of mercury in those lamps is in a semi-solid state. It's quite soft and it doesn't exist as a vapour after the lamp is broken or when the lamp is cold.
You can't inhale it.
It only vapourises about a minute after the lamp has been switched off.
This is about as clear as mud. Mercury is a liquid at room temperature so of course it is 'soft'. The lamps work by vapourising Mercury within the tube to cause it to emit radiation. It is vapourised from the moment it is turned on to when it is turned off.
Mercury also vapourises at room temperature. If you smash a bulb, don't breath in. The safe level of mercury according to the environmentalists own protection agency (EPA) is about 0.2ug per m3 of air. If your room is say an average 35m3 then breaking a bulb has the potential raise the level to 140 ug per m3, which is 700 times the limit*. Of course it will do this slowly, but it is still dodgy.
5mg of Mercury is enough to contaminate about 400,000 litres of water in a lake. If we buy 10 million light bulbs a year, and they all get thrown out in 5 years, that is 50kg of Mercury, or 4 million cubic metres of contaminated water. Put another way, just one year's dumping of these bulbs could contaminate the water behind the proposed Coalgate Dam that the environmentalists are complaining about.
So what is my point? Well, let people choose what bulbs they want in their house, what fillings they want in their teeth and what type of thermometers they have in the house. Forcing people to fill their house up with mercury bulbs is not the way to go.
Also, environmentalists are guilty of hypocracy for going on about Hg poisoning from power generation, but actively encouraging it from bulbs.
* Like environmentalists trying to make a point I have omitted a key fact - did you spot it? Unless you have hot carpet or brush / vacuum the mercury, or try to rub it out of the carpet with detergent, it doesn't all vapourise instantly - it could take up to an hour to fill the room to a dangerous level. So the risk is not 700x higher than the limit, in practice. Of course the bad news is that it doesn't vapourise instantly: it will still be at detectable levels in the room for months, and there is enough mercury to keep the level dangerous for a month. Make sure you get it all!
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