Fluorotelomer precursors in soil constitute a reservoir for perfluoroalkyl acids (PFAAs) in the environment. In the present study, precursor degradation and transfer rates of seven fluorotelomer precursors and F-53B (chlorinated polyfluoroalkyl ether sulfonates) were investigated in pot experiments with maize plants (Zea mays L.). The degradation of fluorotelomer precursors to perfluoroalkyl carboxylic acids (PFCAs) and their uptake spectra corresponded to those of fluorotelomer alcohol (FTOH) in terms of the number of perfluorinated carbon atoms. Short-chain PFCAs were translocated into the shoots (in descending order perfluoropentanoic, perfluorobutanoic, and perfluorohexanoic acid), whereas long-chain PFCAs mainly remained in the soil. In particular, fluorotelomer phosphate diesters (diPAPs) were retained in the soil and showed the highest degradation potential including evidence of α-oxidative processes. F-53B did not degrade to PFAAs and its constituents were mainly detected in the roots with minor uptake into the shoots. The results demonstrate the important role of precursors as an entry pathway for PFCAs into the food chain.

In this study, 6:2 and 8:2 polyfluoroalkyl phosphate diester (diPAP) were individually investigated in lysimeters under near-natural conditions. Leachate was sampled for 2 years, as was the soil after the experiment. In the leachate of the diPAP-spiked soils, perfluorocarboxylic acids (PFCAs) of different chain lengths were detected [23.2% (6:2 diPAP variant) and 20.8% (8:2 diPAP variant) of the initially applied molar amount]. After 2 years, the soils still contained 36-37% 6:2 diPAP and 41-45% 8:2 diPAP, respectively, in addition to smaller amounts of PFCAs (1.5 and 10.6%, respectively). Amounts of PFCAs found in the grass were low (<0.1% in both variants). The recovery rate of both 6:2 diPAP and 8:2 diPAP did not reach 100% (63.9 and 83.2%, respectively). The transformation of immobile diPAPs into persistent mobile PFCAs and their transport into the groundwater shows a pathway for human exposure to hazardous PFCAs through drinking water and irrigation of crops.

Blood sampling by venepuncture is a routine procedure in animal experiments and veterinary diagnostics. It can cause stress due to restraint and pain associated with a penetration of the skin by a needle. When stressful procedures are repeated, stress can increase through anticipation after negative experiences or decrease due to habituation and/or positive reinforcement. The aim of this study was to describe the reaction to repeated blood sampling on the affective state of the animals. We wanted to observe how repeated blood sampling would effect stress parameters in goats in a experiment with repeated blood sampling that underwent an intensive cooperative vet care training and were handled with focus on gentle handling. Eight dairy goats underwent weekly blood sampling over a four-month period as part of a transfer study. Stress parameters were assessed by serum cortisol concentration, temperature changes in the inner corner of the eye measured by infrared thermography, and an ethogram of voluntary and aversive behavior. Neither the serum cortisol concentration nor the eye temperature changed significantly over time during blood sampling. However, the ethogram showed that the goats approached the blood sampling position significantly faster and more voluntarily. In this study we observed that repetition of blood sampling not necessary lead to increased stress. However, the voluntary behavior of the trained goats increased over time as a result of positive reinforcement training and habituation.

Blood sampling by venipuncture is a routine procedure used in animal experiments and veterinary diagnostics. It can cause stress due to restraint and pain associated with penetration of the skin by a needle. When stressful procedures are repeated, stress can increase through anticipation after negative experiences or decrease due to habituation and/or positive reinforcement. The aim of this study was to describe the reaction to repeated blood sampling on the affective state of the animals. We wanted to observe how repeated blood sampling would affect stress parameters in goats that underwent an intensive cooperative vet care training protocol and were managed with a focus on gentle handling. Eight dairy goats underwent weekly blood sampling over a four-month period as part of a transfer study. Stress parameters were assessed using serum cortisol concentration, temperature changes in the inner corner of the eye measured by infrared thermography, and an ethogram showing voluntary and aversive behavior. Neither the serum cortisol concentration nor the eye temperature changed significantly over time during blood sampling. However, the ethogram showed that the goats approached the blood sampling position significantly faster and more voluntarily. In this study, we did not observe changes within the measured physiological stress parameters due to repeated blood sampling over three months. However, the voluntary behavior of the trained goats increased over time as a result of positive reinforcement training and habituation.

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic substances, which moved to the scientific focus due to their ubiquity in the environment. Several thousands of individual PFAS are known, which differ in chemical structure as well as in their chemical and physical properties. Due to the huge number of substances, the assessment of their environmental behaviour is challenging. Still, more information about these substances, which are partly already declared PBT (persistent, bioaccumulative and toxic), is needed for risk assessments and remediation.The overall aim of this study was to describe the environmental behaviour in soil during leaching of ten different PFAAs (perfluoroalkyl acids), a group of persistent PFAS, and two diPAPs (polyfluoroalkyl phosphate diesters) with physical equations and parameters to gain knowledge about substance-related characteristics. For this purpose, we simulated the leaching of all surveyed PFAAs and of the biodegradable precursors 6:2 diPAP and 8:2 diPAP, which can transform into PFAAs. Soil and percolation data received from two experimental studies, a laboratory soil column study and a field lysimeter study, were used to evaluate the leaching and transformation behaviour using the MACRO model. In both studies the behaviour of diPAPs were simulated, which enables a comparison between natural and unnatural conditions. Modelling results from the laboratory study, in which climate impacts are limited, were used as input for the field study with natural climatic conditions. Parameters used for calibration were substance-related such as the adsorption distribution coefficient (KD). The amount of non-recovered PFAS, which is potentially related to the formation of non-extractable residues (NERs), was described using a first-order degradation equation. The evaluation of simulations was done using the goodness-of-fit function KGE (Kling-Gupta Efficiency) and a fitting score comparing simulated and observed soil and percolation data. Optimisation was done using the caRamel evolutionary algorithm with multi-objectives within the GNU R environment and up to 15,000 runs per substance, which resulted in a pareto front. Results of parameter values were then used to describe their leaching behaviour as transformation products (PFAAs) of diPAPs in two steps: (1) optimisation of leaching and transformation of diPAPs with soil data, (2) simulation of leaching of transformation products using results of PFAA simulations. The preliminary modeling results are promising for simulating the behavior of PFAAs as well as their precursors with MACRO.

The transfer of per-and polyfluoroalkyl substances (PFAS), in particular of perfluoroalkyl acids (PFAAs), via feed into livestock and subsequently into food of animal origin represents a relevant pathway for consumer exposure. We investigated the transfer and toxicokinetics of multiple linear (n-) and branched (br-)PFAA isomers in lactating dairy goats fed hay from a contamination site in Germany for eight weeks, followed by a twelve-week depuration. Samples of hay, blood serum, milk and milk fractions were analyzed for PFAA content using UHPLC-MS/MS. Hay averaged 1034.7 µg/kg PFAAs (43% branched isomers). PFAAs accumulated in blood serum and transferred to the milk, reaching maximum total concentrations of 1757.5 µg/L and 59.6 µg/kg, respectively. Overall, 2.7% of ingested PFAAs were excreted via milk. The milk transfer rates were highly substance- and isomer-specific, peaking for long-chain PFSAs and PFCAs at 10.4% (n- and br-PFOS) and 8.9% (n-PFDA), beyond which they declined linearly. Linear isomers exhibited significantly higher transfer rates than their branched counterparts. While PFBA and PFOA were eliminated rapidly, long-chain PFAAs showed slow elimination. PFCAs showed significantly longer milk half-lives than PFSAs with equivalent perfluorinated chain lengths. The longest milk half-lives were 89.6 days (br-PFUnDA) and 42.5 days (n-PFDA), while n-PFOS reached 31.0 days. Milk fractionation revealed preferential PFAA accumulation in fat- and protein-rich matrices; cream contained the highest levels (176.1 µg/kg dry matter). Ultimately, the transfer potential and slow elimination of several PFAAs underscore their relevance for human dietary exposure, supporting the inclusion of linear and branched isomers in future food safety risk assessments.