Transfer of Per- and Polyfluoroalkyl Substances (PFAS) from Feed into the Eggs of Laying Hens. Part 2: Toxicokinetic Results Including the Role of Precursors

Abstract

A feeding study was performed to examine the bioaccumulation of per-and polyfluoroalkyl substances (PFAS) in laying hens' tissues and plasma and feed-to-egg transfer rates and half-lives. A 25 day exposure was followed by a 42 day depuration period. A target analysis revealed substantial amounts of the precursors N-methyl and N-ethyl perfluorooctane sulfonamidoacetic acid (Me-and EtFOSAA), perfluorooctane sulfonamidoacetic acid (FOSAA), and perfluorooctane sulfonamide (FOSA). In tissues and eggs, the highest bioaccumulation was found for PFHxS, PFHpS, PFOS, and PFOA. Low levels of PFHxS (all samples), PFOS, and FOSAA (in yolk) were measurable even after the depuration period. The egg elimination half-lives of PFOS and aforementioned precursors were estimated to be 4.3 days, while the transfer rates of PFOS and all precursors taken together were 0.99. The transfer rate of PFOA was around 0.49. PFHxS and PFHpS showed apparent transfer rates of >100%, which is hypothesized to indicate the presence of precursors.

Degradation and Plant Transfer Rates of Seven Fluorotelomer Precursors to Perfluoroalkyl Acids and F-53B in a Soil-Plant System with Maize (Zea mays L.)

“…17 Many studies have investigated the pathways of PFASs, especially PFAAs, from aerobic soils to leaching and uptake into agricultural plants, as this makes them an important source of human exposure via drinking water, 26 plant-based foods (such as cereals) 27 and food-producing animals. 28 Recently, Lesmeister et al presented a review on the uptake of PFASs in crops and included studies on precursor degradation. 29 Existing studies on precursor degradation in soil and PFAS plant uptake have generally considered only a few precursors in one study.…”

PFAS: forever chemicals—persistent, bioaccumulative and mobile. Reviewing the status and the need for their phase out and remediation of contaminated sites

“…By means of the TOP assay (Total Oxidizable Precursorsee "Sum parameters for PFAS" section), which also recognizes numerous unknown precursors, it can be shown that the concentrations of the PFAS sum in sediments and in bream are often many times higher than the values of individual determinations [113,114]. The transfer of contaminants to humans via food can be seen, for example, in the analysis of eggs from chickens that were fed with feed from a contaminated site [115,116].…”

Food, Beverage, and Feedstock Processing Facility Wastewater: a Unique and Underappreciated Source of Contaminants to U.S. Streams

“…Many of the products produced by facilities in this study originate from the production of livestock and crops. Research has documented multiple agricultural pathways for PFAS exposure, including municipal biosolids application, municipal wastewater irrigation, livestock waste, fertilizers, and pesticide containers. − In addition to the possible raw food material source, industrial uses of PFAS could contribute to the detections in FPWW; the U.S. Food and Drug Administration lists gaskets, O-rings, and other parts used in food processing equipment, processing aids to reduce buildup on manufacturing equipment, and grease-proofing agents in paper and paperboard food packaging as authorized uses of PFAS in food contact applications . The variation in both the number of PFAS detections and concentrations is supported by the variety of industry types sampled.…”