11 August 2010

Are we trading our carbon footprint for a mercury one?

David Vaughan
A compact fluorescent lamp (CFL). Photo courtesy Nioxxe

David Vaughan is the Two Oceans Aquarium’s aquatic animal health researcher. He conducts research into various fish parasites and other health issues affecting aquatic animals at the Aquarium.

Awareness of humankind’s negative impact on the planet due to increased amounts of carbon dioxide and other greenhouse gases has increased dramatically over the last few years. One of the major contributors of excessive carbon dioxide emissions is undoubtedly our use of fossil fuels and the by-products of their various chemical constituents.

In April 2008, South Africa experienced mandatory loadshedding as a result of a lack of capacity in Eskom, South Africa’s electricity utility. Eskom currently runs 22 power stations of which 13 (59%) of these are coal-fired, with an additional two coal-fired power stations proposed for future construction in 2012.

Arguably, one of the most successful campaigns to reduce our electricity consumption has seen the inclusion of national electricity consumption alerts on TV and radio, Eskom’s rebate programme and initiatives to replace incandescent light bulbs with compact fluorescent lamps (CFLs).

CFLs, also known as power-saving lamps, typically use only about 30% of the electricity required by their incandescent congeners. Their lifespan, depending on how they are used, can be up to 10 times that of incandescents. Local supermarkets have been actively encouraging and marketing these power-saving lamps, and some stores have almost completely replaced their stock of incandescents with CFLs to increase the incidence of purchase and therefore home-lighting replacement.

This in itself certainly reduces overall electricity consumption in the home and office, helping reduce carbon levels. However, the devil is always in the detail, and most of us fail to recognise how the use of CFLs has increased the amount of mercury waste, and the impact of this on the environment.

Mercury is present in all fluorescent tubes, which includes CFLs, and is also released from coal-fired power stations during the burning process. Ironically, by increasing our usage of CFLs over incandescents, however, we are maintaining our inevitable impact of mercury toxicity on our environment – including the oceans.

“Mercury contamination of fish and mammals is a global public health concern,” says Michael Bender, a member of the Zero Mercury Working Group. “Our study of fish tested in different locations around the world shows that internationally accepted exposure levels for methylmercury are exceeded, often by wide margins, in each country and area covered.”

Carbon-reduction is probably the lesser of these two evils. Historically however, humans seem to replace one problem with another … Something to ponder.

More blogs by David:

Tokolosh discovered at the Aquarium!

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