Those concerned about the mercury in compact fluorescent light bulbs should consider what the primary source of mercury contamination in North America is: coal-fired power plants. A report prepared earlier this year expects mercury levels in the Pacific to double by 2050, as the result of emissions from new coal plants.
This is especially relevant in places where summers are hot, since we might be paying a double climate and mercury price for the heat being produced by incandescent bulbs. If air conditioning is being used to get rid of it, the bulbs may well have negative efficiency in addition to their role in poisoning water supplies through those coal plant emissions.
All this is yet another reason why coal is the enemy of the human race.