Arsenic Mobility at the Groundwater-Surface Water Interface


This project focuses on the factors controlling the mobility of heavy metals, including arsenic, at the groundwater-surface water interface. Arsenic is a carcinogenic heavy metal that is elevated in groundwater in many aquifers worldwide. In some cases elevated arsenic concentrations can be attributed to anthropogenic activities (e.g., mining and industry) but often arsenic is naturally occurring in aquifers.

Iron minerals are the main natural sources of arsenic and redox cycling of these minerals is strongly linked to arsenic occurrence and mobility in groundwater. Shifting redox conditions in aquifers, as often occurs near the groundwater-surface water interface, can lead to the accumulation of arsenic on the mineral phases with subsequent release to the surface waters. Natural nanoparticles, which are abundant in groundwater systems, can also serve as a potential vector for arsenic transport. Mechanisms governing nanoparticle transport (e.g., Brownian motion, aggregation, sedimentation, pore exclusion) differ from that of purely dissolved phase species. As such consideration of nanoparticle facilitated arsenic transport may be required to fully understand arsenic cycling in aquifers.

Project Objectives

The research aims to evaluate:

  1. Influence of dynamic groundwater-surface water interactions on redox cycling and arsenic mobility.
  2. Factors controlling the accumulation and mobilization of arsenic at the groundwater-surface water interface.
  3. Importance of nanoparticle facilitated arsenic transport and implications for the traditional thermodynamic approach to reactive species transport.

Project Team

Team Members: