To assess the risks over the longer term, it is necessary to document dietary exposure to pollutants associated with the fire that could accumulate and migrate via other environmental media such as water, soil and plants. Soil can lead to contamination through direct ingestion by animals, transfer to plants that are then ingested by animals and humans, or transfer through the hydrological network.
ANSES's recommendations for the surveillance strategy are designed to protect consumer health from chronic exposure to contaminants through food.
ANSES's experts incorporated into their work the results from 606 samples taken from food products up to 18 October 2019. Their analysis mainly involved mapping the distribution of samples for the four main food families: eggs, dairy products, vegetables and animal feed, according to INERIS's modelling of the impact of soot deposition from the plume. Analysis of the maps did not show any clear correlation between deposition intensity and concentrations of contaminants analysed in the samples, apart from a trend for dioxins, furans and polychlorinated biphenyls in eggs.
On the basis of this analysis and a draft plan drawn up by the authorities, the Agency is issuing recommendations in order to finalise the surveillance strategy to be put in place.
ANSES reiterates the importance of measuring environmental contamination, particularly in the soil. The recommended surveillance scheme can then be adapted according to the results of these samples, which are not yet available.
The experts identified and prioritised different substances to be screened for in each food family: plant products for humans and animals, milk, meat, eggs from free-range farms, farmed fish, honey, livestock feed stored outdoors and pasture grass. The substances correspond to the contaminants screened for during the first sampling phase: dioxins and furans, PCBs, PAHs, trace metal elements and fire-extinguishing products.
The Agency recommends determining the sampling sites within the area affected by the plume, which was identified by INERIS's modelling. This sampling is expected to be carried out over a year, taking into account the agricultural production seasons. In addition, some samples should be taken from the farms already involved in the first phase, in order to measure changes over time since the fire.
Furthermore, priority should be given to open-field crop production over crops grown in greenhouses or tunnels, and to production from animals reared outdoors.
On the basis of its previous opinions, ANSES recommends that samples mainly be taken from:
- foodstuffs of animal origin intended for human consumption: milk, eggs (with an emphasis on free-range farms) and farmed fish;
- root vegetables;
- maize silage.
Compiling all the data from these environments will help identify the contaminants associated with the smoke plume produced by the fire and guide the various efforts to monitor population exposure.