Occurrence of selected perfluorinated alkyl acids in lunch meals served at school canteens in Italy and their relevance for children’s intake

Uptake of perfluorinated alkyl acids by crops: results from a field study

Four crops with different edible plant parts (radish, lettuce, pea and maize) were grown in outdoor lysimeters on soil spiked with 13 perfluorinated alkyl acids (PFAAs) at 4 different levels. PFAA concentrations were measured in soil, soil pore water, and different plant parts at harvest. Edible part/soil concentration factors ranged over seven orders of magnitude and decreased strongly with increasing PFAA chain length, by a factor of 10 for each additional fluorinated carbon (nCF) for pea. Three processes were responsible for most of the variability. The first was sorption to soil; calculating whole plant concentration factors on the basis of concentration in pore water instead of soil reduced the variability from five orders of magnitude to two. Second, the journey of the PFAAs with the transpiration stream to the leaves was hindered by retention in the roots driven by sorption; root retention factors increased by a factor 1.7 for each nCF. Third, transfer of PFAAs from the leaves to the fruit via the phloem flow was also hindered - presumably by sorption; fruit/leaf concentration factors decreased by a factor 2.5 for each nCF. A simple mathematical model based on the above principles described the measured concentrations in roots, leaves, fruits and radish bulbs within a factor 4 in most cases. This indicates that the great diversity in PFAA transfer from soil to crops can be largely described with simple concepts for four markedly different species.

Determination and assessment of human dietary intake of per and polyfluoroalkyl substances in retail dairy milk and infant formula from South Africa

Dairy milk and infant formula play important roles in the diet of adolescents, adults and infants, respectively, in the South African population. However, data on the occurrence of legacy and emerging contaminants such as PFAS in these important food sources is lacking. In this study, the concentration of fifteen PFAS were measured in 23 pooled retail dairy milk and 7 pooled infant formulas by means of an ultrahigh performance liquid chromatography tandem mass spectrometric method. The concentrations of Σ₁₅PFAS ranged from 0.08-15.51 ng mL^-1 and 0.42-5.74 ng mL^-1 in dairy milk and infant formulas, respectively. PFBA, PFPeA, PFuDA, PFTrDA and PFDoA were the most prevalent PFAS in both matrices with detection frequency > 96%. Highest PFAS concentrations of 2.02 ng ml^-1 and 2.76 ng ml^-1 were recorded for PFDoA in infant formulas and dairy milk, respectively. The concentrations of legacy PFAS -PFOA and PFOS, shows resemblance with global data, however, elevated concentrations of long chain C₉ - C₁₄ PFAS were observed in this study. Though, higher concentrations of PFAS were measured in full cream dairy milk, no statistical significant difference (P = 0.546) was observed for the various classes of dairy milk. The EDI of Σ₁₅PFAS through infant formulas were 184.92, 329.47 and 166 ngkg^-1BWday^-1 for partially breastfed, exclusively formula fed and older infants, respectively. Similarly, the EDI of PFAS through dairy milk for toddlers, adolescents, female and male adults for the rural population were 14.17, 1.09, 2.59 and 3.16 ngkg^-1BWday^-1 respectively while they were 20.41, 3.84, 4.13 and 4.26 ngkg^-1BWday^-1 respectively in the urban population. Although, the EDI of PFAS through the consumption of infant formulas and dairy milk are lower than the daily tolerable limits, the relative importance of long-term exposure and the cumulative effects of multiple exposure pathways cannot be overemphasized.

Children's exposure to perfluoroalkyl acids - a modelling approach

Adults are mainly exposed to per- and polyfluoroalkyl substances (PFASs) via ingestion of food, inhalation of air and ingestion of dust, whereas for children the exposure to PFASs is largely unknown. This study aimed to reconstruct the serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) in children after infancy up to 10.5 years of age and to test if dietary intake is the major exposure pathway for children to PFOA, PFOS and PFHxS after infancy. For this work, a dataset from a Finnish child cohort study was available, which comprised serum concentrations of the studied perfluoroalkyl acids (PFAAs) and PFAS concentration measurements in dust and air samples from the children's bedrooms. The calculated PFAA intakes were used in a pharmacokinetic model to reconstruct the PFAA serum concentrations from 1 to 10.5 years of age. The calculated PFOA and PFOS intakes were close to current regulatory intake thresholds and diet was the major exposure medium for the 10.5 year-olds. The one-compartment PK model reconstructed median PFOA and PFOS serum concentrations well compared to corresponding measured median serum concentrations, while the modelled PFHxS serum concentrations showed a constant underestimation. The results imply that children's exposure to PFOA and PFOS after breastfeeding and with increasing age resembles the exposure of adults. Further, the children in the Finnish cohort experienced a rather constant exposure to PFOA and PFOS between 1 and 10.5 years of age. The PFHxS exposure sources and respective pharmacokinetic parameter estimations need further investigation.

Elevated concentrations of perfluorohexanesulfonate and other per- and polyfluoroalkyl substances in Baiyangdian Lake (China): Source characterization and exposure assessment

Novel 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and legacy PFASs, such as perfluorohexane sulfonate (PFHxS), have been used to replace perfluorooctane sulfonate (PFOS), a known persistent organic pollutant. Thus, it is critical to understand these PFOS alternatives regarding their sources and concentrations in the natural environment. In this study, 41 surface water samples as well as edible aquatic organisms were collected from Baiyangdian Lake, the largest freshwater lake in Hebei Province, China. Perfluorooctanoate acid (PFOA) and PFHxS were the predominant PFASs detected in the surface water, reaching concentrations of 8 397.23 ng/L and 1 478.03 ng/L, respectively, with PFHxS accounting for the greatest proportion (∼80.00%) in most water samples. PFHxS (mean: 87.53 ng/g) and PFOS (mean: 35.94 ng/g) were also the most prevalent compounds detected in aquatic organisms. Estimated daily intake (EDI) values of PFOS (16.56 ng/kg bw/d) and PFHxS (16.11 ng/kg bw/d) via aquatic food and drinking water were the highest among PFASs, indicating potential exposure risks to residents. In addition, fish product consumption was the important exposure pathway for residents to PFOA, PFHxS, PFOS, and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA). This study reports on the highest PFHxS levels ever recorded in surface water, suggesting that further quantification of PFHxS in human serum and assessment of its health risks to local residents are warranted and critical.

Per- and Polyfluoroalkyl Substances (PFASs) in Food and Human Dietary Intake: A Review of the Recent Scientific Literature

Because of the important environmental presence and the potential human toxicity of per- and polyfluorinated alkyl substances (PFASs), in recent years the social and scientific interest in these compounds has notably increased. Special attention has been paid to perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), the most extensively investigated PFASs. Although human exposure to PFASs may occur through different pathways, dietary intake seems to be the main route of exposure to these compounds. In 2012, we published a wide revision on the state of the science regarding the concentrations of PFASs in foodstuffs, the human dietary exposure to these compounds, and their health risks. In the present review, we have updated the information recently (2011-2016) published in the scientific literature. As in our previous review, we have also observed considerable differences in the PFASs detected-and their concentrations-in the food items analyzed in samples from a number of regions and countries. However, fish and other seafood seem to be the food group in which more PFASs are detected and where the concentrations of these compounds are higher. On the basis of the recommendations of the EFSA on the maximum dietary intakes of PFOS and PFOA, human health risks would not be of concern for nonoccupationally exposed populations, at least in the very limited countries for which recent data are available.