Improving Long-term Monitoring of Contaminated Groundwater at Sites where Attenuation-based Remedies are Deployed

Abstract

This study presents an effective approach to tackle the challenge of long-term monitoring of contaminated groundwater sites where remediation leaves residual contamination in the subsurface. Traditional long-term monitoring of contaminated groundwater sites focuses on measuring contaminant concentrations and is applicable to sites where contaminant mass is removed or degraded to a level below the regulatory standard. The traditional approach is less effective at sites where risk from metals or radionuclides continues to exist in the subsurface after remedial goals are achieved. We propose a long-term monitoring strategy for this type of waste site that focuses on measuring the hydrological and geochemical parameters that control attenuation or remobilization of contaminants while de-emphasizing contaminant-concentration measurements. We demonstrate how this approach would be more effective than traditional long-term monitoring, using a site in South Carolina, USA, where groundwater is contaminated by several radionuclides. A comprehensive enhanced attenuation remedy has been implemented at the site to minimize discharge of contamination to surface water. The immobilization of contaminants occurs in three locations by manipulation of hydrological and geochemical parameters, as well as by natural attenuation processes. Deployment of our proposed long-term monitoring strategy will combine subsurface and surface measurements using spectroscopic tools, geophysical tools, and sensors to monitor the parameters controlling contaminant attenuation. The advantage of this approach is that it will detect the potential for contaminant remobilization from engineered and natural attenuation zones, allowing potential adverse changes to be mitigated before contaminant attenuation is reversed.

A Review on Applications of Time-Lapse Electrical Resistivity Tomography Over the Last 30 Years : Perspectives for Mining Waste Monitoring

“…Electrical resistivity could then be used as a proxy indicating possible AMD generation or migration from the wastes, as it has already been done in the past for other types of contaminants (e.g., Denham et al. ( 2020 ); Heenan et al. ( 2015 )).…”

Reactive transport modeling for supporting climate resilience at groundwater contamination sites

“…Changing climate may pose a major risk in environmental remediation, especially with regard to fate and transport, including both hydrologic and reactive processes (Maco et al, 2018). In particular, many sites are managed with monitored natural attenuation strategies where an expanded contamination plume with high concentrations of tritium, uranium, and other chemical species remains in the subsurface (Denham et al, 2020). Hydrological shift has been identified as one of the key drivers influencing such risk and uncertainty.…”

Metodologia para Confecção de Mapas Potenciométricos em Aquíferos Cársticos e Físsuro-Cársticos: Estudo de Caso na Alta Bacia do Rio Corrente, Mambaí, GO

“…A potenciometria pode ser definida como a energia mensurável da água, que é responsável pelo seu movimento e fluxo no interior do aquífero (Denham et al, 2020). A partir da avaliação das linhas isopiezas, o fluxo percola de um ponto de carga hidráulica maior para um de menor potencial (Peralta e Kowalski, 1986;Roy e Zahid, 2021).…”