Chemical Speciation of Antarctic Atmospheric Depositions

Both inorganic and organic complexation of metal cations in clouds or rainwater is essential to describe the global biogeochemical cycles of metals, because complexation can increase metal solubility and stabilize some of their oxidation states. Within a Project of the National Research Program in t...

Full description

Bibliographic Details
Published in:Applied Sciences
Main Authors: Stefano Bertinetti, Silvia Berto, Mery Malandrino, Davide Vione, Ornella Abollino, Eleonora Conca, Matteo Marafante, Anna Annibaldi, Cristina Truzzi, Silvia Illuminati
Format: Text
Language:English
Published: Multidisciplinary Digital Publishing Institute 2022
Subjects:
Online Access:https://doi.org/10.3390/app12094438
Description
Summary:Both inorganic and organic complexation of metal cations in clouds or rainwater is essential to describe the global biogeochemical cycles of metals, because complexation can increase metal solubility and stabilize some of their oxidation states. Within a Project of the National Research Program in the Antarctica, atmospheric depositions were collected during the Antarctic summer 2017ā€“2018 in eight sampling sites. The main ionic components occurring in water extracts of these atmospheric depositions were quantified, and a chemical model was applied, in order to identify the main species occurring in the samples. The speciation study showed that most cations were present as aquoions, except for Fe, which occurred predominantly in hydrolytic forms. The model allowed us to foresee the effect of an increase in the concentration levels of all the solution components, by simulating what could happen when the original particles act as cloud condensation nuclei. The role of inorganic anions as complexing agents becomes important when increasing total concentrations of all the solutes by a factor >100 compared to the water extracts, while the presence of organic acids acquires significance for samples having organic acid concentration higher than 10āˆ’5 mol Lāˆ’1. Moreover, it was possible to pinpoint the formation constants that mostly affect the chemical system, and to gain insight into the behavior of metals in wet depositions, which is fundamental knowledge in atmospheric photochemistry studies and in the modeling of the biogeochemical cycles of metal cations.