Pathways and factors for food safety and food security at PFOS contaminated sites within a problem based learning approach

• Food of animal origin can play a pivotal role in food exposure in PFOS hot spot areas.
• Eggs from rural flocks may represent an emerging PFOS source.
• Advisories and implemented farming practice may reduce PFOS food intake by up to 75%.
• PFOS contaminated sites are problematic, due to its bioaccumulative feature.
• Level of soil contamination may represent a key factor both for food safety.

Perfluorooctanesulfonic acid (PFOS) and related substances have been listed in Annex B of the Stockholm Convention. The implementation requires inventories of use, stockpiles, and environmental contamination including contaminated sites and measures for (risk) reduction and phase out. In most countries monitoring capacity is not available and therefore other approaches for assessment of contaminated sites are needed. Available informations about PFOS contamination in hot spot areas and its bio-accumulation in the food webs have been merged to build up a worst-case scenario We model PFOS transfer from 1 to 100 ng L−1 range in water to extensive and free-range food producing animals, also via the spread of contaminated sludges on agriculture soils. The modeling indicates that forages represented 78% of the exposure in ruminants, while soil accounted for >80% in outdoor poultry/eggs and pigs. From the carry-over rates derived from literature, in pork liver, egg, and feral fish computed concentration falls at 101, 28 and 2.7 ng g−1, respectively, under the 1 ng L−1 PFOS scenario. Assuming a major consumption of food produced from a contaminated area, advisories on egg and fish, supported by good agriculture/farming practices could abate 75% of the human food intake. Such advisories would allow people to become resilient in a PFOS contaminated area through an empowerment of the food choices, bringing the alimentary exposure toward the current Tolerable Daily Intake (TDI) of 150 ng kg−1 body weight d−1 proposed by the European Food Safety Authority (EFSA).