# Temperature Modulates PFAS Accumulation and Effects on Metabolic Performance in Sheepshead Minnows

## TL;DR

Warmer temperatures increase the effects of PFAS pollution on fish metabolism and health, potentially harming coastal fish populations.

## Contribution

This study reveals how warming temperatures interact with PFAS to alter fish physiology and detoxification costs.

## Key findings

- Temperature altered PFAS accumulation in fish tissues, especially promoting PFOA redistribution to eggs.
- At higher temperatures, PFAS exposure reduced maximum metabolic rates and aerobic scope in fish.
- PFAS exposure increased hepatosomatic index, suggesting increased detoxification costs.

## Abstract

Climate warming and
chemical pollution shape aquatic ecosystems,
yet the physiological mechanisms underlying their combined effects
remain unclear. We investigated how projected increases in mean summer
surface water temperature alter per- and polyfluoroalkyl substance
(PFAS) toxicokinetics and their effects on the physiological performance
of sheepshead minnows (Cyprinodon variegatus). Adult fish were chronically exposed to an environmentally relevant
PFAS mixture (perfluorooctanesulfonate (PFOS) + perfluorooctanoate
(PFOA)) under current and projected mean-temperature scenarios. Tissue
PFAS concentrations, whole-organism metabolic rates, swimming performance,
reproductive output, and somatic indices were assessed. Temperature
modified PFAS tissue concentrations in a compound- and tissue-specific
manner, notably promoting PFOA redistribution to eggs. Metabolic responses
were temperature-dependent: at 26 °C, higher tissue PFAS concentrations
were associated with elevated standard and maximum metabolic rates
(SMR and MMR), maintaining aerobic scope (AS). At 28.5 °C, SMR
remained stable while MMR and AS declined with rising PFAS, indicating
less oxygen for energetically demanding activities. Despite unchanged
performance outcomes for swimming and reproduction, increase in hepatosomatic
index with increasing tissue PFAS concentrations and altered PFAS
distribution suggests detoxification costs. These findings indicate
that increases in mean water temperature are likely to exacerbate
contaminant stress, with consequences for coastal fish population
resilience and offspring development. PFAS risk assessment should
consider costressors under projected warming.