Advances in metal(loid) in situ soil remediation and potential influences of changing environmental conditions

Authors: SOWERS, TYLER - Us Environmental Protection Agency (EPA); Fischel, Matthew; PEEL, HANNAH - Us Environmental Protection Agency (EPA); FISCHEL, JASON - Us Environmental Protection Agency (EPA); BETTS, AARON - Us Environmental Protection Agency (EPA); BONE, SHARON - Institute Of Bio- And Geosciences: Agrosphere (IBG-3)

Submitted to: Advances in Agronomy
Publication Type: Review Article
Publication Acceptance Date: 7/25/2025
Publication Date: 8/25/2025
Citation: Sowers, T.D., Fischel, M.H., Peel, H.R., Fischel, J.S., Betts, A.R., Bone, S.E. 2025. Advances in metal(loid) in situ soil remediation and potential influences of changing environmental conditions. Advances in Agronomy. 194:1-53. https://doi.org/10.1016/bs.agron.2025.07.002.
DOI: https://doi.org/10.1016/bs.agron.2025.07.002

Interpretive Summary: Chromium, mercury, arsenic, uranium, and lead are toxic contaminants in soils worldwide that cause significant harm to human health and the environment. However, the procedures used to clean up these contaminants in soils often rely on excavation instead of the newest techniques that employ chemical transformation and stabilization to decontaminate these toxins, which is less costly and more environmentally friendly. This manuscript synthesizes the most recent developments in toxic contamination cleanup and extrapolates their efficacy under current and projected environmental destabilization, including sea level rise, wildfires, and flooding. This literature review includes information on remediation using chemical stabilization with minerals to bind the contaminants, plants to uptake and remove contaminants, and methods to help mitigate contaminant destabilization from natural disasters. The manuscript will aid policymakers in deciding how to regulate the cleanup of sites containing mercury, chromium, lead, arsenic, and uranium using updated techniques and help prevent contaminant transport during natural disasters with the ultimate impact of reducing human exposure and safeguarding human health against these deadly toxins in an ever-changing environment.

Technical Abstract: Soils ubiquitously contain metal(loid)s that may have severe implication on human and ecosystem health. Increased understanding of the toxicity and mobility of metal(loid) contaminants has intensified the need for remediation options that reduce exposure. Metal(loid) biogeochemistry and soil heterogeneity greatly impact design and implementation of remediation methods; however, fluctuating environmental conditions due to sea level rise, flooding, and/or wildfires create further complications. Here, we discuss a subset of in situ remediation methods that represent promising options for treating high priority metal(loid) contaminants. Specifically, lead, mercury, arsenic, chromium, and uranium are discussed to evaluate unique chemistries expected from highly toxic cation, oxyanion, and radionuclide contaminants. Mobility of these elements when subjected to significant environmental changes – sea level rise, flooding, and wildfires – are also explored. Ultimately, there is a dearth of insight into how remediated contaminants may respond when exposed to changing soil conditions promoted by shifts in the surrounding environment. Further exploration of these phenomena is essential to understanding inorganic contaminant biogeochemical cycling and estimated reduction in exposure post-remediative action.