Mengelers M, te Biesebeek JD, Schipper M, Slob W, Boon PE
RIVM Report 2018-0017
As a result of emissions from the DuPont/Chemours chemicals company in Dordrecht, the substances GenX and PFOA have been emitted into the environment via the air. As a consequence, persons with a vegetable garden in the vicinity of the company are not sure whether it is safe to eat their home-grown vegetables. A study carried out by RIVM concludes that the threshold values of GenX and PFOA that apply to exposure are not exceeded via food. However, residents are also exposed to these substances via air and drinking water. Therefore, RIVM advises that vegetable garden crops grown within a radius of 1 kilometre from the company should be consumed in moderation (not too often or too much). The concentrations found within this area were somewhat higher. Outside this area, the concentrations were so low that the crops can be safely consumed even if one takes into account the two other sources of exposure.
The study at hand is based on the calculation of the exposure to GenX and PFOA via home-grown vegetables for persons with a vegetable garden located within a radius of 4 kilometres from the factory. At the end of August 2017, samples were taken of vegetables at ten different locations, namely at three locations in Dordrecht and Papendrecht and at four locations in Sliedrecht. A location in Bilthoven was sampled for purposes of comparison. Samples were taken of three categories of vegetables at all the locations, namely leafy vegetables, root vegetables, and fruiting vegetables. At one of the locations, two fruit crops were also sampled. A total of 81 samples were analysed.
GenX and/or PFOA were found to be present in approximately 40% of the samples in the vicinity of the factory. GenX was found to be present in measurable quantities in 14% of the samples in the vicinity of the factory, and the same was true of PFOA in 4% of the samples. At concentrations less than 1 nanogram per gram, it was not possible to determine the exact quantity, but only that the substance was present. At one location, less than 1 kilometre north-east of the factory, higher concentrations of GenX (in endive, beets, celery, lettuce, and tomatoes) and of PFOA (in beets) were found to be present in vegetables than at the other nine locations close to the factory.
The highest concentrations were used to calculate the exposure. The calculation was based on the assumption that the persons in question would eat daily only vegetables from their own garden throughout their lifetime. The calculated results are therefore probably higher than the actual exposure to GenX and PFOA of vegetable garden owners in the vicinity of the factory. Under these worst-case circumstances, the exposure to both substances via food did not exceed the threshold values that are considered safe (the so-called health-based guidance values).