Occurrence of arsenite in surface and groundwater associated with a perennial stream located in Western Nebraska, USA

Authors

Arindam Malakar, University of Nebraska - LincolnFollow
Rajesh Singh, National Institute of Hydrology, Roorkee, India
Jeffrey Westrop, University of Nebraska-LincolnFollow
Karrie A. Weber, University of Nebraska-LincolnFollow
Christopher N. Elofson, University of Nebraska Lincoln
Manish Kumar, Indian Institute of Technology Gandhinagar
Daniel D. Snow, University of Nebraska-LincolnFollow

Date of this Version

2021

Citation

Published in Journal of Hazardous Materials 416 (2021) 126170

doi:10.1016/j.jhazmat.2021.126170

Comments

Copyright © 2021 Elsevier B.V. Used by permission

Abstract

Dissolved arsenic typically results from chemical weathering of arsenic rich sediments and is most often found in oxidized forms in surface water. The mobility of arsenic is controlled by its valence state and also by its association with iron oxides minerals, the forms of which are both influenced by abiotic and biotic processes in aqueous environment. In this study, speciation methods were used to measure and confirm the presence of reduced arsenic species in the surface water of Frenchman creek, a gaining stream that crosses the Colorado- Nebraska border. Selective extraction analysis of aquifer and stream bed sediments shows that the bulk of the arsenic occurs with labile iron-rich oxy(hydroxide) minerals. Total dissolved arsenic in surface and groundwater ranged from ~3–18 μg L^–1, and reduced arsenic species comprise about 41% of the total dissolved arsenic (16.0 μg L^–1) in Frenchman creek. Leachable arsenic in the aquifer sediment samples ranged up to 1553 μg kg^–1, while samples from Frenchman creek bed sediments contained 4218 μg kg^–1. Dynamic surface and groundwater interaction sustains arsenite in iron-rich surface headwaters, and the implied toxicity of reduced arsenic in this hydrogeological setting, which can be important in surface water environments around the globe.