4-Nonylphenol in Sierra Nevada glaciers, California, USA

ABSTRACT

Persistent organic pollutants are stored in environmental reservoirs globally. Tracking the mass and movement of these pollutants is critical for assessing environmental health for human and wildlife populations. Recently, glaciers have been identified as secondary reservoirs for persistent organic pollutants. Downstream lakes and rivers have increased risk of exposure with climate change and loss of glacier mass. Two glaciers, Palisade and Middle Palisade Glaciers, in the Sierra Nevada Mountains, California, United States, were modeled for total mass of the persistent organic pollutant, 4-nonylphenol (4NP). The model used LiDAR measurements of surface snow and geographic information systems (GIS) to extrapolate vertical and horizontal 4NP gradients. Concentrations of 4NP in surface snow were sampled in locations based on a range of topographical shielding indices and analyzed via gas chromatography–mass spectrometry. The Middle Palisade Glacier, the smaller and more shielded glacier, had a total mass of 1,677 ± 560 kg 4NP/km². The Palisade Glacier, which is larger and more exposed to atmospheric deposition, held an estimated 3,456 ± 843 kg 4NP/km². Meltwater concentrations for the Middle Palisade and Palisade Glaciers were 1.3 ± 0.05 μg/L and 6.1 ± 1.3 μg/L, respectively. These values demonstrate that both glaciers store a significant amount of 4NP and will act as secondary sources of 4NP for downstream water bodies.

KEYWORDS:

• Persistent organic pollutants
• glacier reservoirs
• 4-nonylphenol
• Sierra Nevada mountains

Acknowledgments

This work could not have been done without the support of the Center for Spatial Studies at the University of Redlands. Specifically, we thank Nathan Strout and Lisa Benvenuti for their contributions. We also acknowledge the hardworking students who helped with the fieldwork, specifically Anthony Hua, Tyler Strabel, Graeme Cubitt, Sebastian Gallardo, and Sasha Karapetrova. As always, thanks to Dr. Jim Bentley for his thoughtful and thorough statistical assistance. We appreciate the helpful modeling suggestions from Dr. Andreas Linsbauer at the University of Zurich.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded in part by a Spatial Inquiries Grant from the Center for Spatial Studies at the University of Redlands.