Controls on the persistence of aqueous-phase groundwater contaminants in the presence of reactive back-diffusion
Landon James Szasz Halloran & Daniel Hunkeler
| Résumé |
The persistence of groundwater contaminants is influenced by several
interacting processes. Physical, physico-chemical, and
(bio-)chemical processes all influence the transport of
contaminants in the subsurface. However,for a given
hydrogeologicalsystem, itisgenerally unclear to whichdegree each of
these phenomena acts as a con-trol on plume behaviour. Here, we
present a comprehensive investigation of these processes and their
influenceson plume behaviour and persistence in layered sedimentary
systems. We investigate different scenarios that
rep-resentfundamental configurationsof common
contaminantsituations. A confined aquifer over- and underlain
byaquitard layers is investigated in a source-removal scenario and
a constant-source equilibrium scenario. Addi-tionally, an aquitard
overlain and underlain by high permeability units is investigated
in a source-removal sce-nario. In these investigations, we vary
layer thickness, as well as parameters governing advection,
(back-)diffusion, sorption, and degradation. Extensive analysis of
these results enables quantification of the influenceof these
parameters on maximum down-gradient concentration, plume
persistence duration, and plume spatialextent. Finally,
parameterspace dimensionality reductionisused to establishtrends
and regimes inwhichcertainprocesses dominate as controls. A lower
limit to plume extent as a function of a novel constructed
parameter isalso determined. These results provide valuable
quantitative information for the assessment of the fate
ofgroundwater contaminants and are applicable to a wide range of
aqueous-phase solutes. |
| Mots-clés |
Plume persistence; Back-diffusion Sorption Sensitivity analysis Groundwater contaminants; Reactive transport |
| Citation | James Szasz Halloran, L., & Hunkeler, D. (2020). Controls on the persistence of aqueous-phase groundwater contaminants in the presence of reactive back-diffusion. Science of the Total Environment, 722, 137749-137764. |
| Type | Article de périodique (Anglais) |
| Date de publication | 3-2020 |
| Nom du périodique | Science of the Total Environment |
| Volume | 722 |
| Pages | 137749-137764 |
| URL | https://doi.org/10.1016/j.scitotenv.2020.137749 |