If you drive on the highway between Bern and Zurich, you will see at some point (in Kölliken) a huge metallic, white structure somewhat looking like one of these artificial ski resorts which have been flourishing here and there around the world. However what this gigantic cage contains is not snow, but roughly 550 000 tons (!) of waste, mostly toxic chemicals, stored here completely unlabeled, unclassified and without any kind of precaution. Among others, drums with production residues from the chemical industry, electroplating sludges, phosphoric waste, oil contaminated soil, or bag containing unsorted loose waste were delivered to the landfill. In 1985, foul smells and strangely-colored dusts lead to the dump to be closed – at that time, this meant the waste was covered by around 10 meters earth… It was then observed that underground water was becoming polluted, threatening the drinking water. The authorities finally decided the site had to be decontaminated and the waste properly treated.

An impressive draining system was build to prevent water flowing under the contaminated area from polluting further ground water. Then the huge building (of a total surface equivalent to that of ten football pitches) covering the whole area was built, and kept under slightly reduced pressure such as to prevent any escape of dust, gas or odors. The access to the main building is severely restricted, and one can enter only fully equipped with airtight suit and oxygen supply. There, samples are prelevated from rust covered tanks to try and identify what had been buried 25 years ago. The waste are then separated and sent for proper treatment. This goes not without any risk, since in summer 2008 a violent fire suddenly broke out, due to fortuitous contact between magnesium and air moisture…

A view of the inside of the main building.

This is shown in this impressive video recorded by safety cameras (in Swiss-German, but the images really show how ruined the place is, and what are the working conditions. Another video (in French) can be found here telling about the landfill.

If everything goes as planned, the waste evacuation should last until 2012, and the area should ‘look like before’ in 2015. The cost of the whole operation will likely reach 1 billion swiss francs (ca. 965 millions US$) – a good sum just to repare mistakes from the past. The good news is that is was acknowledged at some point that these mistakes were putting populations and environment at risk, and appropriate arrangements were made in order to fix the situation, whatever the costs were to be. There are some lessons to take home there!

For more informations

The society responsible for the decontamination of the landfill: SMDK (in German)

Osmium (named after the greek ‘osme’, meaning smell) is a trace element found in sea water and earth crust, particularly in platinum ores. It is usually mentioned in undergrad teaching for being the heaviest element with a density of 22600 kg/m³ or because its above-mentioned derivative, osmium tetroxide, is extremely toxic (it is also a smelly compound, hence the metal’s name).

A team led by Mukul Sharma at Dartmouth College investigated the osmium-187 vs osmium-188 ratios in various locations on earth. In deep seawater (samples were collected 2000m deep in Atlantic ocean) this ratio is roughly equal to 1, whereas in platinum ores, there is usually 5 times more Os-188 than Os-187. Remarkably, samples obtained from surface seawater or rain showed an intermediate ratio, i.e. enriched in Os-188 compared to deep seawater. It is then very likely that extracted osmium (i.e. with an increased amount of Os-188) from (mainly) platinum ores is slowly dissipated into the atmosphere. Platinum is indeed widely used for the production of automobile catalytic converters. Refinement processes of platinum after mining occur at very high temperatures (~1000°C), and osmium traces can be converted into very volatile osmium tetroxide. In the absence of appropriate exhaust gases scrubbing systems, osmium is then released in the atmosphere. This, the authors say, is not directly endangering us since the involved quantities are far too small, but it provides us with another hint on how industrial processes are able to modify our ecosystems, sometimes in unexpected ways!

Ref:

C. Chen et al., Proc. Natl. Acad. Sci. USA 2009, 106, 7724. doi: 10.1073/pnas.0811803106