The authorities have posted online Wednesday the mapping of lead dust samples on the ground since the fire of Notre-Dame in April, while the latest child screening did not reveal new cases of over-contamination .
The Regional Health Agency (ARS) of Ile-de-France has put online a “dynamic cartography” recording the samples taken from the public space – by the public authorities or the communes – and made public a modeling of the plume of smoke cleared during the disaster, confirming that the fallout in lead are the strongest close to the fire .
1,072 lead level measurements
At the end of October, 1,072 measurements of lead levels were carried out since the April 15th fire on children and young people in the districts of Paris closest to the cathedral (1st, 4th, 5th, 6th and 7th).
Twelve cases exceeded the threshold for mandatory reporting of lead poisoning (50 micrograms of lead per liter of blood) “which remains at the level of the global population, but does not present at this stage of over-contamination,” said the regional director of the ARS Aurélien Rousseau. In 11 of these 12 cases, “we found a source of contamination at home”, particularly because of the presence of lead in buildings Haussmann, he said presenting these results to the press.
Of the 1,060 other cases, 96 revealed a “vigilance” threshold requiring a six-month check. The previously noted trends are therefore confirmed.
From Paris to Mantes-la-Jolie
In addition, the ARS commissioned the Ineris (French institute for the industrial environment and risks) to model the smoke plume of the fire, in order to specify its trajectory towards the west and to evaluate the quantity of lead dust that he could lead.
While recognizing “significant uncertainty”, Ineris estimated that some 150 kilograms of lead dust were released into the atmosphere, with some 460 tons of lead in the roof and spire of the cathedral.
The plume stretched to Mantes-la-Jolie in the Yvelines is almost 50 kilometers. In the three scenarios modeled, the neighborhoods of Paris or the suburbs located on the path of the plume were the most affected.
No contamination in Yvelines and Hauts-de-Seine
The ARS has made a hundred additional samples taken during November, following this modeling. In Yvelines and Hauts-de-Seine, no measurement exceeded 300 micrograms per square meter, for a “benchmark” of 5,000 μg / m2, beyond which the ARS has set up targeted screening and decontamination operations. In Paris, all measurements were less than 1,000 μg / m2, except one at 1,400. These measures “do not present inconsistencies with respect to modeling,” said Laurence Rouil, head of “environmental modeling” of Inéris.
In addition, they confirm the initial hypothesis that the largest fallout of lead occurred in the 800-meter zone around the cathedral – not modeled by the Ineris – by projections during collapses, for example by the smoke.
The forecourt of the cathedral still contaminated
Thus the rates recorded on the forecourt, still closed to the public, are still high, with measures at 30,000 or 40,000 μg / m2, said Aurélien Rousseau. “Several cleaning campaigns have lowered these levels, but not enough,” he said, noting that “the very nature of the pavement (soil) makes cleaning very difficult.” Moving rubble can also lead to “reissues” of lead.
The reconstruction site remains “permanently monitored”, including blood lead exams for people working there, said the head of the ARS.