Sea-level rise and Arsenic-rich soils: A toxic relationship

Authors: IZADITAME, FATEMEH - The University Of Texas At Dallas; LEMONTE, JOSHUA - Brigham Young University; SEIBECKER, MATTHEW - Texas Tech University; YU, XUAN - Chinese Academy Of Sciences, Nanjing Branch; Fischel, Matthew; TAPPERO, RYAN - Brookhaven National Laboratory; SPARKS, DONALD - University Of Delaware

Submitted to: Journal of Hazardous Materials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2024
Publication Date: 5/10/2024
Citation: Izaditame, F., Lemonte, J., Seibecker, M., Yu, X., Fischel, M.H., Tappero, R., Sparks, D. 2024. Sea-level rise and Arsenic-rich soils: A toxic relationship. Journal of Hazardous Materials. 472: Article e134528. https://doi.org/10.1016/j.jhazmat.2024.134528.
DOI: https://doi.org/10.1016/j.jhazmat.2024.134528

Interpretive Summary: Arsenic is a toxin that impacts human and environmental health across the globe. It is a common pollutant in soils and water released from industrial manufacturing and some rocks. In this study we determined the amount of arsenic pollution in an industrial site in Wilmington, Delaware that faces future disturbance from sea level rise and storm events. The experiments showed exceptionally high levels of arsenic, but the chemistry indicates it was mostly in a stable form that is less toxic. These results help inform decisions to clean up this site and others like it all along the eastern United States. The results also help inform scientists and policy makers of the level of risk associated with arsenic in coastal areas with future climate change to help reduce harm to human and environmental health.

Technical Abstract: Arsenic, one of the most prevalent toxic elements in the environment, occurs commonly within the urban sediments as a result of abundant industrial and agricultural-related activities. Within the United States, As has been detected in nearly 20% of public groundwater supplies, and elevated levels of As are present at more than a third of the U.S. EPA’s superfund sites on the National Priorities List. The risks that As-bearing sediments pose to ecosystems and humans depend on the solid-phase chemical speciation of As and its environmental mobility. In this study, we adopt an integrated geochemical approach to investigate and determine the long–term fate of As in urban coastal sediments taken from a Superfund site in Wilmington, DE. The distribution, speciation, and mineral phases of As in sediments are studied using synchrotron-based X-ray micro–fluorescence (µ-XRF) coupled with micro-focused X-ray absorption spectroscopy (µ-XAS), bulk X-ray absorption near edge spectroscopy (XANES), and micro X-ray diffraction (XRD) analysis. The spectroscopic analysis is further combined with a five-step sequential extraction technique to assess the geochemical distribution of As in the sediments. Total As content in the collected sediments ranged from 400 – 60,000 mg kg–1 with 32% of the average total As in the residual As fraction. Results show that As(III) and As(V) species are present in the sediments and are mainly associated with Fe- and Mn-oxides. The µ-XRF images demonstrate a concomitant occurrence of As, Mn, and Fe. Being mainly sorbed to Fe and Mn oxides suggests that As in these sediments could potentially desorb from these oxides if these phases undergo a reduction in anoxic conditions such as flooding and sea-level rise (SLR). The information provided in this study will help in deciding on the best remedial action strategy for this and other As contaminated sites.