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January 5, 2021
LIFE PHOENIX: environmental monitoring results

The monitoring activity carried out within the LIFE PHOENIX project made it possible to quantify the level of irrigation water and agricultural soil contamination in one of the areas most impacted by PFAS release. The study was specifically focused on PFAS determination in plants, in which these compounds were occasionally found. In particular the attention was paid on PFAS uptake in edible crops in order to provide information for human risk assessment due to vegetable consumption.

Figure 1 shows the concentrations of PFAS recorded in the considered environmental matrices. The levels of these compounds in irrigation waters are characterized by a high variability due to the different water supply throughout the year. Events of higher contamination were occasionally recorded. On the other hand, soil pollution reflects the area classification based on different levels of PFAS pressures: the highest concentrations were indeed found in samples from the red area while the lowest levels were detected in those from the green area. This matching was not observed in plants whose contamination level was similar in the three areas, regardless of sampling site. It is also noteworthy that PFAS concentrations in edible plant samples (onion, lettuce, corn kernels) were lower than those measured in spontaneous species and never exceeded 2 ng/g per wet weight.

Figure 1: PFAS concentrations in samples. The range (min and max) and the average level (in brackets) are shown in table. LOD (Limit of Detection) represents the analytical detection limit.
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Figure 1: PFAS concentrations in samples. The range (min and max) and the average level (in brackets) are shown in table. LOD (Limit of Detection) represents the analytical detection limit.
Figure 2: PFAS contamination in samples. Short- (C<8) and long-chain (C≥8) compounds are represented in shade of blue and red, respectively.
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Figure 2: PFAS contamination in samples. Short- (C<8) and long-chain (C≥8) compounds are represented in shade of blue and red, respectively.
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PFAS is a group of heterogeneous substances with different chemical-physical properties. The behaviour of these compound is mainly driven by the length of their fluorinated alkyl chain. In accordance with this, regardless of sampling site, irrigation water contamination was dominated by more water-soluble short-chain compounds (C <8), while soil was mainly polluted by more lipophilic long-chain PFAS (C≥8). On the contrary, the composition of vegetal contamination was affected by the sampling site (Figure 2). In particular, plants collected in the green area were mainly polluted by long-chain compounds (C≥8), released in the past, while short-chain chemicals (C<8), of more recent origin, were dominant in vegetable samples taken in the red area, which is directly impacted by the fluorochemical plant discharge in surface waters.