An individual living in the 1980s contained lead concentrations 10,000 times higher than those observed in pre-historical skeletons. Pollution linked to the industrial revolution and the use of leaded petrol, at the beginning of the previous century, are not without having a bearing in this respect. Thanks to work done at the ULg on peat bogs, the presence of this metal in the environment is starting to deliver its secrets. On the strength of this knowledge the scientific community can now get down to tackling two other large challenges: understanding better the persistence of lead in today’s environment (despite the banning of leaded petrol) and studying the recent increase in incidents of Saharan desert sand being blown to our latitudes.

Tourists rambling on the Hautes-Fagnes plateau last year would have come across a strange human team harnessed together and weighed down with cumbersome metallic appliances. Its goal: to get to the site known as Misten, one of the best preserved in the natural park, and to dig down into the peat to a depth of a dozen metres. In this genuine ecological jewel, which is difficult to access, even for to scientists, every step counts: vandalising the bog moss by misplaced trampling is out of the question. Through the strictly manual use of a sample taking apparatus these privileged guests contented themselves in delicately taking long samples of peat which were to be split into segments, dried and then analysed in some of the country’s specialised laboratories. The objective: to root out from them information on the history of the last 10,000 years.

Peaks of lead pollution

The ‘Misten’ fen, its heart miraculously spared by activities linked to drainage and exploitation, is however the icing on the cake for the Liège scientists. The peat bogs of the Hautes-Fagnes - we sometimes have a tendency to forget - are some of the best preserved in Europe. ‘They are quite specific,’ comments Gaël Le Roux, a young researcher originally from Brittany, working at the heart of the University of Liège’s Clays, Environmental and Sedimentary Geo-chemistry team (AGEs), formed within the Department of Geology. Their large surface area, their ecological diversity and their geological and geomorphological particularities make of them a natural environment which is unique in Europe. To find others which offer the same interest it is necessary to travel to Scandinavia or northern Scotland. And what is more, there the sites are still being exploited! Biotopes of such a kind have completely disappeared in France and Germany! (1)'

(1) Such peat bogs, fed by exclusively airborne nutriments, are called ‘Ombrotophic’.