Chromium speciation and mobility in contaminated coastal urban soils affected by water salinity and redox conditions

Piyapas Sricharoenvech; Matthew G Siebecker; Ryan Tappero; Gautier Landrot; Matthew H H Fischel; Donald L Sparks

doi:10.1016/j.jhazmat.2023.132661

Chromium speciation and mobility in contaminated coastal urban soils affected by water salinity and redox conditions

J Hazard Mater. 2024 Jan 15:462:132661. doi: 10.1016/j.jhazmat.2023.132661. Epub 2023 Sep 29.

Authors

Piyapas Sricharoenvech¹, Matthew G Siebecker², Ryan Tappero³, Gautier Landrot⁴, Matthew H H Fischel⁵, Donald L Sparks⁶

Affiliations

¹ Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USA. Electronic address: pypschrv@udel.edu.
² Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA.
³ Photon Sciences Division, Brookhaven National Laboratory, Upton, NY 11973, USA.
⁴ Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin 91192, Gif-sur-Yvette, France.
⁵ Sustainable Agricultural Systems Laboratory, USDA-Agricultural Research Service, Beltsville, MD, 20705, USA.
⁶ Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, USA.

PMID: 37837776
DOI: 10.1016/j.jhazmat.2023.132661

Abstract

Chromium (Cr) is a redox-sensitive element in contaminated coastal urban soils. Sea level rise (SLR) with subsequent soil inundation may facilitate Cr transformation and mobilization through alterations in local redox conditions and porewater ion composition. We investigated the impact of water salinity and redox conditions on Cr chemistry in these environments. Synchrotron-based X-ray spectroscopy and wet chemical analyses revealed that the soils contained very high levels of Cr (up to 4320 mg kg^-1) and that chromite (∼52%) and Fe-Cr hydroxide coprecipitates (∼44%) were the predominant Cr species. The abundance of these two components resulted in low Cr mobility under non-flooded conditions. Chromium(II) was identified in the soils, potentially derived from the waste parent material. Seawater and anoxic conditions resulted in lower Cr release compared to freshwater and aerobic conditions. Up to three to eight times more Cr was released under aerobic conditions versus anaerobic conditions in the freshwater versus saltwater, respectively, with total dissolved Cr values remaining below 0.02 mg L^-1. The decrease in Cr release was likely due to Cr reduction by Fe(II) and sulfide. This work provides important information on how salinity and redox fluctuations impact Cr cycling which is likely to occur during SLR.

Keywords: Chromite; Cycling; Flooding; Sea level rise; X-ray absorption spectroscopy.