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, Palisades and Middle Palisades Glaciers, in the Sierra Nevada Mountains, CA, USA were modeled for total mass of the persistent organic pollutant, 4-nonylphenol (4NP). The model used LiDAR measurements of surface snow, and 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 GC/MS. The Middle Palisades Glacier, the smaller and more shielded glacier, had a total mass of 1677±560 kg 4NP/km². The Palisades Glacier, which is larger and more exposed to atmospheric deposition, held an estimated 3456±843 kg 4NP/km². Meltwater concentrations for the Middle Palisades and Palisades Glaciers were 1.3±0.05 μg 4NP/L meltwater 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.