In Vivo Bioavailability and In Vitro Bioaccessibility of Perfluorooctanoic Acid (PFOA) in Food Matrices: Correlation Analysis and Method Development

Abstract

Food is a major source of human exposure to perfluorooctanoic acid (PFOA), however, PFOA bioavailability in food has not been studied. An in vivo mouse model and three in vitro methods (unified BARGE method, UBM; physiologically based extraction test, PBET; and in vitro digestion method, IVD) were used to determine the relative bioavailability and bioaccessibility of PFOA in the presence of 17 foods. PFOA was mixed with foods of different nutritional compositions and fed to mice over a 7-d period. PFOA relative bioavailability was determined by comparing PFOA accumulation in the liver following PFOA exposure via food to that in water. PFOA bioavailability relative to water ranged from 4.30 ± 0.80 to 69.0 ± 11.9% and was negatively correlated with lipid content (r = 0.76). This was possibly due to competitive sorption of free fatty acids with PFOA onto transporters on intestine epithelial cells. Besides, cations in the gastrointestinal tract, such as Ca(2+) and Mg(2+), are capable of complexing PFOA and partitioning to the lipid phase. On the other hand, when assessed using in vitro assays, PFOA bioaccessibility varied with methods, being 8.7-73% (UBM), 9.8-99% (PBET), and 21-114% (IVD). PFOA bioaccessibility was negatively correlated with lipid content when assessed using UBM (r = 0.82); however, a poor correlation with food composition was observed for PBET and IVD (r = 0.01-0.50). When in vivo and in vitro data were compared, a strong correlation was observed for UBM (r = 0.79), but poor relationships were observed for PBET and IVD (r = 0.11-0.22). This was probably because the higher lipolysis ability and presence of Ca(2+) and Mg(2+) in the gastrointestinal fluid of UBM resulted in a lower potential to form stable micelles compared to PBET and IVD. These results indicated that PFOA relative bioavailability was mainly affected by lipid content in foods, and UBM has the potential to determine PFOA bioaccessibility in food samples.

Significance of Cooking Oil to Bioaccessibility of Dichlorodiphenyltrichloroethanes (DDTs) and Polybrominated Diphenyl Ethers (PBDEs) in Raw and Cooked Fish: Implications for Human Health Risk

“…Apparently BA% values were not significantly different between native and spiked fish on the basis of either individual DDT components or total DDTs (Figure 2). This confirmed the validity of utilizing spiked samples 14,27,37 to mimic field samples in in vitro digestion experiments. At the same time, previous studies have documented that bioaccessibility was not affected by analyte concentrations at a fixed ratio of the digestive fluid volume to the mass of foodstuff.…”

“…Data Analysis. The bioaccessibility of DDTs and PBDEs in fish, defined as BA%, was calculated by the fraction of target compound mobilized from fish into the gastrointestinal phase with in vitro digestion 14,29…”

“…Bioaccessibility is often estimated with in vitro models, which have been used for heavy metals and persistent organic pollutants (POPs) − among others. As in vitro models may reduce the need for use of laboratory animals and account for matrix effects in risk assessment, they have been used to estimate the bioaccessibility of POPs in different environmental media by many researchers. ,− For example, the bioaccessibility of POPs in food was estimated by a spiking approach to minimize potential analytical uncertainty; , however, it was unclear whether the result was altered artificially due to the use of the spiking method. Fish used for assessing bioaccessibility of POPs are often raw, − but fish consumed are largely cooked.…”

Oral bioaccessibility of semi-volatile organic compounds (SVOCs) in settled dust: A review of measurement methods, data and influencing factors

“…For PCBs 52 and 118 in soil, the relative bioavailability measured in rats' blood was greater than 87% and could not be linked to their bioaccessibility measured by PBET, which produced underestimated results (40% to 80%) [68]. An in vivo/in vitro validation study was also undertaken for PFOA in food, and showed a good correlation (r=0.76, p<0.01) between PFOA bioaccessibility, assessed with the UBM method, and its bioavailability measured in rats' liver [70].…”

Concentrations of perfluoroalkyl substances in human milk from Ireland: Implications for adult and nursing infant exposure

“…While an absorption efficiency of 91% was assumed for both PFOS and PFOA by Thompson et al (2010); other studies (Alves et al 2017;Li et al, 2015) have reported lower values of 11-99% for PFOA -with most solid foods below 70% -and 62 ± 5.6% for PFOS in fish. On this basis, we apply here an intermediate absorption efficiency value of 81%.…”