Nature has unexpected sensors. Students are always astonished to learn that litmus, the simplest of acid-base indicators, is extracted from lichens. Lichens, which have no roots but a thallus, also bioconcentrate SO2 pollution and radioactive fallout from the air. The thallus is the non reproductive part of the lichen that, depending on the genus, can have a variety of appearances as shown below.

There are at least three examples of how lichens have ended up concentrating radioaoctive isotopes:

(1) In studies of fallout following atomic bomb tests in the 1950s, it was found that both Alaskan Eskimos and Scandinavian Laplanders had unusually high levels of radioactive strontium and cesium. This happened even though polar regions received less fallout than tropical areas. The cause? In polar areas, bioconcentration by lichens and subsequent bioaccumulation occurred as the isotopes moved through the food chain from caribou ( who eat reindeer moss which is a lichen) , which are then hunted by Eskimos and Laplanders.

(2) Through the same mechanism, reindeer (what Laplanders call caribou) also became unfit for human consumption after the Chernobyl accident of 1986.

(3) More recently, the concentration of cesium isotopes (¹³⁴Cs and ¹³⁷Cs ) in lichen within a 30 km radius of Fukushima were more than 3 times the acceptable limit.

The Fukushima disaster is a dim reminder of the dire consequences that nuclear energy can have, even when it’s used “peacefully”. A 20-kilometre zone around the reactors had to be evacuated. Food was contaminated and six years later, 97 000 people have still not returned to the area. This includes people who still have to be barred from the region, not just those who opted to live elsewhere. Although it seemed initially that the tidal wave was the primary cause of the nuclear accident, there was in fact serious damage to piping in at least one of the reactors before the tsunami hit them. In the 2015  film Fukushima-a-nuclear-story former Prime Minister Naoto Kan reveals that Tokyo and all of Japan was saved from a much greater catastrophe by chance when a faulty gate caused water to accidentally flow and cool the top of a reactor.

Largely in response to the Fukushima disaster, Switzerland almost voted in favour of a strict timetable for a nuclear power phaseout. And a long-term plan to shift to renewables does exist in a country which presently derives 45% of its electricity from nuclear energy.

Even though nuclear energy is hailed as being carbon-free, I have long held my reservations about the technology. Here’s why.

 (1) There are presently no long-term solutions for the storage of nuclear wastes.

(2) Using nuclear technology to generate electricity is far more expensive than other forms.

(3)  A thorium-based technology is currently not being used, even though it would create less waste. Part of the reason it wasn’t chosen as a fuel is simply because countries have always wanted the plutonium from current uranium-based technology for weapons-purposes. But thorium’s short term radiation from its fission products is harder to contain, which would further raise the costs.

(4) Because of the magnitude of a large-scale explosion, the low probability of its occurrence will be no consolation if it actually occurs. And the likelihood will increase if nuclear power becomes more ubiquitous.

(5) The record of the industry has been far from impeccable and its attitude far from sincere. Things will not get any better with ageing reactors.

Here’s a list of countries that do not use fission reactions to boil water to turn turbines —who,  as I once heard an activist say, “don’t burn the house down to make toast.”

• Australia
• Austria
• Belize
• Cambodia
• Colombia
• Costa Rica
• Greece
• Ireland
• Italy
• Latvia
• Liechtenstein
• Lithuania
• Nepal
• New Zealand
• Peru