Toxic Art – Alexander Calder’s Mercury Fountain

As an occupational hygienist, when visiting the Alexander Calder exhibition at Tate Modern last week I couldn’t help but stop and take notice of the pictures and description of one of the works created by this American artist well known for his mobiles and other “kinetic sculptures” . A mercury fountain.

While I was looking at the display, I overheard a comment by a young woman to her partner as they too read about this work

“It couldn’t have been real mercury could it. That would be dangerous”

I couldn’t help responding

“It was, and it is ”

Mercury, the magical Quicksilver, has been known since ancient times. A metal that’s a liquid at room temperature that flows like water.  Being a liquid, vapours are given off which can be inhaled and it can also be absorbed through intact skin. It’s highly toxic, affecting the brain, gastrointestinal system and kidneys. It’s particularly noted for causing neurological and behavioural disorders due to brain damage. Symptoms include tremors, insomnia, memory loss, neuromuscular effects, headaches and cognitive and motor dysfunction. In Victorian times mercury compounds were used in the manufacture of felt for hats and the workers in that industry were particularly affected. This is said to have inspired Lewis Carroll’s “Mad Hatter” from Alice’s Adventures in Wonderland. This was disputed by the esteemed Professor Hugh Waldron back in 1961, but the myth persists.

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The exhibition website tells us the story of the fountain’s creation

In 1937 Calder was one of the contributors to the Pavilion of the Spanish Republic designed by Josep Lluís Sert for the International Exposition in Paris, where his Mercury Fountain was installed in proximity to Picasso’s painting Guernica. In the middle of the Spanish Civil War, Calder showed his support for the embattled Republic by creating a fountain that would run with mercury from the mines at Almadén – a valuable economic and strategic resource. (Tate website)

A 2007 study of historical exposures of the workers in Almadén mines to mercury indicated that had been very high

In the mine, the highest exposures occurred during drilling, with values up to 2.26 mg/m3 in air, 2194 μg/l in urine and 374 μg/l in blood. Furnace operation and cleaning were the tasks with the highest values in metallurgy, peaking up to 3.37 mg/m3. The filling of bottles with mercury by free fall gave values within a range of 1.13–2.43 mg/m3 in air; these values dropped to 0.32–0.83 mg/m3 after introducing a new ventilation system.

Occupational exposure limits for mercury are typically set at between 0.02 and 0.03mg/m3

I found it a little ironic that a work of art created in support of a government dedicated to improve the lot of working people celebrated an industry likely to have been responsible for poisoning the workers in the mine where it was extracted.

Although it seems likely that visitors to the exhibition back in the 1930’s would have been exposed to mercury vapours, given the relatively short period that they would have been in the vicinity their exposure would have been limited and its highly unlikely there would have been a significant risk to their health. However, I’d be more concerned about the staff working in the Spanish Pavilion.

Today the fountain can be seen at the Fundació Joan Miró museum in Barcelona – carefully displayed under glass. Hopefully appropriate measures are taken to protect the workers who have to maintain it from the toxic liquid and vapours.

Mercury fountain

Picture from the Fundació Joan Miró museum website

Mad as a lighthouse keeper?


Souter Lighthouse, Whitburn

I was up in the North East over the weekend for a family wedding. We stopped overnight and on the way home decided to visit the Souter Lighthouse at Whitburn. Opened in 1871 and operated until 1988, it is now owned by the National Trust. Standing in a dramatic location on the cliffs between the Tyne and Wear, it was the first lighthouse to be powered by electricity.

After looking round the living quarters and the working areas of the complex we were able to climb the tower, accompanied by a guide. It was a steep climb up a spiral staircase and then an almost vertical ladder. According the NT website for the property, there are 76 steps – but it seemed like more!

There was a good view of the coast from the top of the tower, but the main attraction for me was the lamp mechanism.  There are actually two fresnel lenses, one on top of the other. The beam from the lower lens was white while the upper one gave a red light. The whole lamp assembly weighs over four tonnes. It’s supported on a bath of mercury, one and a half tons of the stuff, which has two purposes. First of all it keeps the lamp perfectly level. Secondly it makes it easy to rotate the lamp assembly by reducing friction. We were able to prove this for ourselves by pushing it around with our fingers.

A lighthouse fresnel lens (Source: Wikipedia)

Mercury, of course, is highly toxic, and the lighthouse keepers must have been exposed during their day to day activities, particularly when they had to remove impurities from the top of the bath and also when they had to periodically clean the liquid metal by passing it through a chamois leather, which they had to do every few months. Like most occupational hygienists I’m quite “sad”, I couldn’t help but wonder about what the lighthouse keepers were exposed to, so when I got home I did a search to find out whether anyone has done any work on tthis. I didn’t find much, just two relevant references.

A study on airborne mercury concentrations in lighthouses along with evaluation of urinary mercury levels was carried out in a lighthouse in  Canada in the 1980’s by van Netten and Teschke of  the University of British Columbia (1). The results from the air samples ranged from 4.4 to 26.3 μg/m3.  We don’t have a WEL for mercury in the UK, but the ACGIH TLV is 25 μg/m3 , so the survey certainly suggested that there was some risk that the TLV could be exceeded. Swabs taken on surfaces indicated that there was considerable accumulation of mercury on surfaces in the area of the light rotation mechanism, and other areas in the lighthouse. Urinary levels, however, were relatively low at  <4 μg/24 hr urine. The authors of the study concluded that “mercury levels in this lighthouse appeared to be under control through effective convective ventilation and employee awareness“. I couldn’t find any other studies, but I wonder whether this was typical of lighthouses in general. Today, lighthouses are usually automated and there is much less risk of exposure. However, the levels  reported in the study by van Netten and Teschke from the 1980’s were certainly of concern and it is likely that in the past exposure was even higher.

The second paper I unearthed was particularly interesting. One of the main concerns with mercury is the effect on the central nervous system causing effects such as short-term memory loss, incoordination, weakness, confusion, and psychological changes including the manic behaviour associated with the “mad hatter”.  The paper, by Michaela Walter of the   University of Calgary (2) discussed the possibility of mercury exposure being the cause of  “madness” amongst lighthouse keepers in Canada. According to this paper

“Keepers were not aware of the many dangers of mercury and did not wear protective gear in those days.Another prevailing factor was the amount of time they spent in the area where the lens and lighting system was kept. Keepers routinely cleaned and maintained the lens and mercury bath, lit and cleaned the lamp, as well as reset the gears every three hours t o allow the light to rotate. All of this additional time in the upper area of the lighthouse where the mercury bath was would have allowed for greater exposures to mercury vapour.”

Of course, psychological problems could be explained by other reasons – for example the pressures of working in an isolated location for long periods of time. However, her conclusion is that

“although difficult to substantiate, exposure to potentially toxic levels of mercury is a plausible  explanation for the actions and behaviours displayed by lighthouse keepers during the early 1900’s on the West Coast of Canada.”

We’ve all heard the term “mad as a hatter”, often attributed to the incidence of psychological effects due to mercury amongst workers in the hat manuffacturing industry. Perhaps “mad as a lighthouse keeper” is an alternative!

1. van Netten and Teschke, Assessment of mercury presence and exposure in a lighthouse with a mercury drive system, Environmental Research Volume 45, Issue 1, February 1988, Pages 48-57

2.Lighthouse keeper’s madness: Folk legend or something more toxic? M Walter – History of Medicine Days