# Seasonal Shift in Exposure and Accumulation of PFAS and Heavy Metals in High Arctic Reindeer

## TL;DR

This study finds that reindeer in the Arctic have higher levels of certain pollutants in autumn, likely due to seasonal foraging and long-range transport of contaminants.

## Contribution

The study provides new insights into seasonal variations of PFAS and heavy metals in Arctic reindeer, linking them to long-range transport and environmental change.

## Key findings

- Higher concentrations of THg, Cd, and PFAS were observed in October compared to August.
- PFAS profiles suggest exposure to long-range transported contaminants rather than local sources.
- PFAS concentrations have increased over the past decade, while Cd and Pb have decreased.

## Abstract

Seasonal fluctuations
in contaminant concentrations are an important,
yet often overlooked, aspect of Arctic wildlife monitoring, particularly
in species like the Svalbard reindeer (Rangifer tarandus
platyrhynchus), which exhibit annual fattening and
fasting cycles. While seasonal variation in metal concentrations has
been observed in this species, little is known about how other contaminant
groups, such as per- and poly-fluoroalkyl substances (PFAS), vary
with season. In the present study, we report concentrations of total
mercury (THg), cadmium (Cd), lead (Pb), and 13 PFAS in the liver and
muscle of Svalbard reindeer culled in August 2022 and October 2023.
Seasonal differences were observed, with higher concentrations of
THg, Cd, and several PFAS in October, likely reflecting an extended
foraging time following the winter fasting. The PFAS profiles, dominated
by PFOS and long-chain PFCAs, primarily suggest exposure to long-range
transported contaminants rather than local sources, highlighting that
even remote terrestrial wildlife is affected by emissions from industrialized
regions. While Cd and Pb concentrations have decreased compared to
levels reported in the 1980s, PFAS concentrations have increased over
the past decade. These findings underscore the need for continued
monitoring of Arctic terrestrial wildlife, particularly in the context
of environmental change and remobilisation of legacy contaminants.