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Friday, May 8, 2020 | History

4 edition of Colloid mobilization and transport in contaminant plumes found in the catalog.

Colloid mobilization and transport in contaminant plumes

Colloid mobilization and transport in contaminant plumes

field experiments, laboratory experiments, and modeling

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  • 4 Currently reading

Published by U.S. Environmental Protection Agency, National Risk Management Research Laboratory in Ada, OK .
Written in English

    Subjects:
  • Colloids -- Diffusion rate -- Mathematical models,
  • Groundwater -- Pollution -- Mathematical models

  • Edition Notes

    StatementJoseph N. Ryan ... [et al.]
    SeriesEnvironmental research brief
    ContributionsRyan, Joseph N., National Risk Management Research Laboratory (U.S.)
    The Physical Object
    FormatMicroform
    Pagination38 p.
    Number of Pages38
    ID Numbers
    Open LibraryOL17741800M
    OCLC/WorldCa42359080

    colloid-facilitated contaminant transport can be induced by changes in groundwater solution chemistry, for example decreases in ionic strength and increases in pH. In this study, colloid mobilization and its effect on the transport of Th(IV), an analog for Pu(IV), were investigated.   The collection of papers in this special section of Vadose Zone Journal mainly take their origin, but not exclusively, from an international workshop “Colloids and Colloid-Facilitated Transport of Contaminants in Soil and Sediments” held at the Danish Institute of Agricultural Sciences, Denmark, 19–20 Sept. The workshop was.

      The effects of these basic processes on the contaminant transport are studied. Column experiments are conducted to study the effects of the mobilization and migration of colloidal fines, kaolin on the transport of contaminant, and Ni 2+ metal ion through the sand beds containing kaolin particles under both nonplugging and plugging by: Abstract. Naturally occurring mobile colloids are ubiquitous and are involved in many important processes in the subsurface zone. For example, colloid generation and subsequent mobilization represent a possible mechanism for the transport of contaminants including radionuclides in the subsurface environments.

      Goals / Objectives The purpose of the proposed research is to elucidate mechanisms of water flow, colloid mobilization, and colloid transport in the subsurface environment under unsaturated flow conditions. The project has two main areas of emphasis: (1) to identify the key factors that control colloid mobilization under unsaturated flow conditions; (2) to elucidate the mechanisms . It is known that the persistence, dispersal, long-term transport, and the fate of colloids/pathogens are dependent on regional and local geology and hydrology, electrochemical properties of the colloid/pathogen and the soil, the chemistry of the groundwater, land use and management, and the distribution of potential sources of colloids/pathogens.


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Colloid mobilization and transport in contaminant plumes Download PDF EPUB FB2

The major hypothesis driving this research, that the transport of colloids in a contaminant plume is limited by the advance of the chemical agent causing colloid mobilization, was tested by (1) examining the dependence of colloid transport and mobilization on chemical perturbations, (2) assessing the relative transport of mobilized colloids and the chemicals that caused their mobilization, and.

In both the field andlaboratoryexperiments,goodcorrelationswereobserved between the surface properties of the colloid and aquifer grains and their transport and mobilization behavior. The colloid transport model was developed to describe colloid transport in physically and geochemically heterogeneous porous media similar to that encountered at the field site.

Colloid Mobilization and Transport in Saturated Porous Media "Booklet" of kaolinite -- colloids from Cohansey Sand in the New Jersey Pine Barrens.

Magnification x, scale bar 10 µm. Colloid mobilization and transport in contaminant plumes: field experiments, laboratory experiments, and modeling Author: Joseph N Ryan ; National Risk Management Research Laboratory (U.S.).

facilitated contaminant transport under field conditions. port being determined by both the size and stability of There is a clear need for understanding the processes the dispersed colloids in the soil solution, and by the controlling in situ mobilization and transport of colloids pore size and geometry of the actively conducting pore.

ments from previously published experiments on colloid transport during unsteady flow and permits rigorous assess-ment of our numerical model. Experimental Methods Overview [7] We measured the mobilization and transport of silica colloids in four column experiments.

The columns were packed with quartz sand, which was sieved to a size range. mobilization of existing colloids) and transport (limited by deposition) in model colloid and collector systems has been made in the past few decades. This knowledge of the model systems. Recent field and laboratory experiments have identified colloid-facilitated transport of contaminants as an important mechanism of contaminant migration through groundwater.

For colloid-facilitated transport to be important, three criteria must be met: (1) colloids must be generated; (2) contaminants must associate with the colloids; and (3) colloids must be transported through the by: Emphasis is placed on mobilization of existing colloids by chemical and physical perturbations, the kinetics and dynamics of colloid deposition (filtration) and the “blocking” effect, and the effect of surface chemical heterogeneities on colloid deposition and by: Such colloid-facilitated transport can be induced by changes in groundwater chemistry that occur, for example, when high ionic strength contaminant plumes are displaced by infiltrating rainwater.

Results indicate that in situ colloid mobilization from the initially wet and moderately wet 12% clay soils subjected to matrix-dominated flow behavior was controlled mainly by the time-dependent increase in colloid dispersion, while colloid mobilization from the initially dry soils was limited by the strong and persistent association created Cited by: 1.

Introduction [2] Inorganic colloids mobilized during infiltration events may adsorb contaminants, facilitating their movement through the vadose zone [Vinten et al., ; de Jonge et al., ; Sprague et al., ].The recognition of the potential importance of colloids as agents of vadose‐zone contaminant migration has motivated studies on colloid release and transport through water Cited by:   Contaminant transport in ground water is a contentious issue — especially when it comes to possible movement of radionuclides from nuclear test sites or Cited by: About Cookies, including instructions on how to turn off cookies if you wish to do so.

By continuing to browse this site you agree to us using cookies as described in. Here we will first give a brief introduction to the topic of mobilization and transport of colloids in the vadose zone, and highlight previous evidence of colloid‐facilitated transport.

We then introduce the review and technical papers in the special section. on the role of colloids and complexants on radionuclide and has the distinction of focusing attention on colloid transport.

This group organized the first systematic study transport in the vadose zone. of colloids in the subsurface. The Grimsel colloid exer-cise(Degueldreetal.,)examinedcolloidsinaseries.

It has recently been recognized that mobile colloids may affect the transport of contaminants in ground water. To determine the significance of this process, knowledge of both the total mobile load (dissolved + colloid‐associated) and the dissolved concentration of a ground‐water contaminant must be by: Colloids have been implicated in influencing the transport of actinides and other adsorbed contaminants in the subsurface, significantly increasing their mobility.

Such colloid-facilitated transport can be induced by changes in groundwater chemistry that occur, for example, when high ionic strength contaminant plumes are displaced by infiltrating by: 4. Here we will first give a brief introduction to the topic of mobilization and transport of colloids in the vadose zone, and highlight previous evidence of colloid-facilitated transport.

We then introduce the review and technical papers in the special by: In contaminant plumes, colloids are mobilized and transported with the groundwater. If the advance of the contaminant plume is retarded, the colloids will attempt to move ahead of the plume.

When the colloids re-enter the pristine groundwater, they will be redeposited. In sulphate-reducing soils and sediments, metal sulphide precipitation has been proposed3,4,5,6 to generate contaminant-bearing sulphide colloids, which could transport contaminants traditionally Cited by:   Suspended colloids in subsurface water (e.g mineral fragments, clays, and organic particulates) have been implicated in the transport of colloid-associated contaminants (e.g., heavy metals and radionuclides) that result in soil and groundwater contamination.

11−13 Depending on soil texture and composition, colloid mobilization may also Cited by: in colloid mobilization and transport in unsaturated porous media [El-Farhan et al., ; Saiers et al., ]. [14] Baumann and Niessner [] employ a transparent micromodel to analyze the transport of fluorescent latex microspheres in a three-phase system containing water, air, and octanol.

These researchers show most of the micro-Cited by: