Every upside, almost by definition, has a downside. For example...

Upside: The western world is increasingly switching to
fluorescent, energy-saving lightbulbs.
Downside: They contain mercury, while traditional incandescent bulbs do not.

The bulbs emit the mercury when they're disposed of in dumps. Their makers say this is OK because the amount of mercury emissions from power stations that occur as a result of powering the old-style bulbs is greater than the mercury contained in the energy-saving bulbs.

But, researchers are now saying that the mercury emitted from fluorescent bulbs in landfills is in a vaporous state. This means it gets into the food chain more easily than the mercury emitted by coal-powered power stations. Read more here.

And in case you're wondering: yes, the mercury is necessary. Fluorescent bulbs make light when mercury atoms shift their energy state as a result of a stream of electrons bumping into them.

More environmental downsides to apparent environmental solutions include:

• The presence of benzene, a carcinogen, in lead-free petrol (this problem was recently highlighted in South Africa, but remains problematic in the UK and US as well)
  
• Nickel cadmium, another carcinogen, in most rechargeable batteries
  

Can you think of any others?

Catherine Brahic, online environment reporter

Labels: energy-saving bulbs, mercury