# A Broad Mixture of Linear and Branched Perfluoroalkyl Substances (PFAS) in Hay: Results of an Interlaboratory Comparison

## TL;DR

This study finds high levels of PFAS in contaminated hay, with a notable portion being branched isomers.

## Contribution

The study provides new insights into branched PFAS isomer concentrations in hay through an interlaboratory comparison.

## Key findings

- PFAS concentrations in hay reached up to 148 μg/kg based on 88% dry weight.
- Branched PFAS isomers contributed 31% of the total PFAS content.
- 93% of laboratory results were within acceptable z-score limits.

## Abstract

Poly- and perfluoroalkyl substances (PFAS) are a class
of compounds
with significant economic impact and various applications since the
1950s. Many PFAS accumulate in the environment and pose a threat to
consumers through their transfer along the food chain, and are, therefore,
classified as persistent organic pollutants. In this interlaboratory
comparison, nine laboratories analyzed hay, grown on a highly contaminated
field in Germany, for its PFAS content. In addition, three of these
nine laboratories quantified branched PFAS isomers individually. The
results show that PFAS are present in high concentrations (up to 148
μg/kg based on 88% dry weight; dw), with a considerable contribution
(31%) of branched PFAS in the hay. The study also highlights challenges
in the quantification of branched PFAS due to the lack of commercially
available standard solutions. The performance of the participating
laboratories was excellent, with 93% of the results falling in a z-score range within the acceptable limits of |±2|.