Environmental Science and Pollution Research

, Volume 21, Issue 21, pp 12279–12293

A reactive transport model for mercury fate in soil—application to different anthropogenic pollution sources

  • Bertrand Leterme
  • Philippe Blanc
  • Diederik Jacques
Research Article

DOI: 10.1007/s11356-014-3135-x

Cite this article as:
Leterme, B., Blanc, P. & Jacques, D. Environ Sci Pollut Res (2014) 21: 12279. doi:10.1007/s11356-014-3135-x

Abstract

Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg2+ to Hg0 was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg2+ with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg2+ sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of contaminated sites are discussed.

Keywords

Mercury Hg Reactive transport modelling HP1 Geochemical speciation Vadose zone Leaching 

Supplementary material

11356_2014_3135_MOESM1_ESM.docx (101 kb)
Online Resource 1Selection of the Hg species for the Thermoddem database (DOCX 101 kb)
11356_2014_3135_MOESM2_ESM.docx (24 kb)
Online Resource 2Reactions and exchange constants used in the model but that are not part of the Thermoddem database (DOCX 24.1 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Bertrand Leterme
    • 1
  • Philippe Blanc
    • 2
  • Diederik Jacques
    • 1
  1. 1.Performance Assessments, Institute for Environment, Health, and SafetyBelgian Nuclear Research Centre (SCK•CEN)MolBelgium
  2. 2.D3E/BGE, Bureau de Recherches Géologiques et Minières (BRGM)OrleansFrance