Levels of dioxins and furans were detected in the heights of Lausanne. Following tests carried out in collaboration with the canton on 49 sites in town, eighteen exceeded the limit value. Access to nine of them considered sensitive has been restricted.
Dioxin pollution was observed within the framework of the agro-ecological park project on the plots of the City between Chailly and La Sallaz. “The file is serious, but we are not in a state of alarming crisis”, declared Natacha Litzistorf, Lausanne director of housing, environment and architecture, Wednesday in front of the press.
No danger for drinking water
Following this discovery, the City turned to the township, which carried out additional analyzes on 49 nearby sites. The authorities want to be reassuring: by respecting the usual preventive measures, this old pollution does not present an imminent threat to health. It is probably linked to the operation of the former Vallon factory, added the municipal. Analyzes on the site will provide more information.
Dioxins are organic substances that are persistent, in principle, generated by a combustion process and deposited on the ground by the air. They were generated between the years 1920 to 1970. Today, these releases are severely limited, continued Cornélius Neet, Director General of the Environment in the canton of Vaud.
The current facilities, the Tridel factory, the Vidy WWTP and the Montoie crematorium are not in question. The city’s drinking water supply is not threatened by this pollution either.
Measurements at nine sites
Of the 18 places where the limit value of 100 “toxic equivalent nanograms per kilogram of soil”, decreed by the Confederation, has been exceeded, nine so-called sensitive require emergency measures. In particular to protect young children likely to ingest soil, explained the Vaud environmental manager.
This is essentially the area around playgrounds and sports fields, at Sauvabelin, at the Hermitage or at the Place du Nord, said Natacha Litzistorf. As a preventive measure, information panels and barriers will be put in place within a week.
“However, a child would have to absorb soil daily for it to constitute a danger,” explained Professor David Vernez, head of the Health, Work and Environment Department at Unisanté, responsible for assessing the risks of this. contamination.
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A “diffuse and low” risk
The area where land is likely to contain this dioxin goes from the Usine du Vallon to Victor-Ruffy and may concern private gardens. It is recommended to wash and peel vegetables and wash your hands after gardening. The molecules do not attach to vegetables, said the professor.
As dioxin accumulates in animal fats, it is better to avoid eating meat or eggs from chickens evolving on these grounds. The City also asks the public not to consume the woolly pig rillettes from Sauvabelin and to bring them back to their places of purchase.
If the ingestion of polluted soil proves to be harmful or even carcinogenic in the long term, it would be necessary to absorb a significant quantity of it, four times a week throughout the year for this to represent a danger. The risk is diffuse and low. It’s not Seveso, noted Cornelius Neet [en référence à la catastrophe écologique et sanitaire qui s’est produite dans la commune italienne du même nom en 1976, ndlr].
Sanitation measures to be defined
The City immediately shelved its agro-ecological park project where the former Aeby farm and its market were located. Who in his time was able to sell vegetables from contaminated land. But these are generally washed before consumption, noted Natacha Litzistorf.
As for what follows, investigations will be carried out to examine other sensitive sites by the end of July. Then, the canton will decide on reorganization measures. An information line for the general public has been opened on 021 315 96 96.
The authorities have also noted that if worrying values have been discovered (between 100 and 300), the danger threshold has been established at 1000 in France and Germany. In addition, in Switzerland, there were almost no concrete cases of dioxin pollution analyzed that would have allowed the comparison, noted the municipal.