Phosphorus speciation and solubility in aeolian dust deposited in the interior American West

Environmental Science & Technology
By: , and 



Aeolian dust is a significant source of phosphorus (P) to alpine oligotrophic lakes, but P speciation in dust and source sediments and its release kinetics to lake water remain unknown. Phosphorus K-edge XANES spectroscopy shows that calcium-bound P (Ca−P) is dominant in 10 of 12 dust samples (41−74%) deposited on snow in the central Rocky Mountains and all 42 source sediment samples (the fine fraction) (68−80%), with a lower proportion in dust probably because acidic snowmelt dissolves some Ca−P in dust before collection. Iron-bound P (Fe−P, ∼54%) dominates in the remaining two dust samples. Chemical extractions (SEDEX) on these samples provide inaccurate results because of unselective extraction of targeted species and artifacts introduced by the extractions. Dust releases increasingly more P in synthetic lake water within 6−72 h thanks to dissolution of Ca−P, but dust release of P declines afterward due to back adsorption of P onto Fe oxides present in the dust. The back sorption is stronger for the dust with a lower degree of P saturation determined by oxalate extraction. This work suggests that P speciation, poorly crystalline minerals in the dust, and lake acidification all affect the availability and fate of dust-borne P in lakes.

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Publication type Article
Publication Subtype Journal Article
Title Phosphorus speciation and solubility in aeolian dust deposited in the interior American West
Series title Environmental Science & Technology
DOI 10.1021/acs.est.7b04729
Volume 52
Issue 5
Year Published 2018
Language English
Publisher ACS Publications
Contributing office(s) Geosciences and Environmental Change Science Center
Description 10 p.
First page 2658
Last page 2667
Country United States
State Arizona, Colorado, New Mexico, Utah
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