Jump to ContentJump to Main Navigation
Soil Water Dynamics$
Users without a subscription are not able to see the full content.

Arthur W. Warrick

Print publication date: 2003

Print ISBN-13: 9780195126051

Published to Oxford Scholarship Online: November 2020

DOI: 10.1093/oso/9780195126051.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2021. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 23 June 2021

Solute and Contaminant Transport

Solute and Contaminant Transport

(p.298) 7 Solute and Contaminant Transport
Soil Water Dynamics

Arthur W. Warrick

Oxford University Press

We now look at the transport of materials in soil systems. Not only do water and liquids move, but so also do a variety of chemical and biological constituents. In this chapter, the emphasis will be on flow processes involving water that is carrying different types of solute. The solutes of interest can be harmful or they can be beneficial. The same chemical species could be desirable when contained within one region and undesirable if it escapes to another—such as from the root zone to the ground water. Both conservative and reactive tracers will be discussed. A conservative tracer is assumed to move freely with the soil water and is non-reactive, non-volatile, and non-absorbing. Of course, this is only an ideal case, and all materials carried with water will react in some way with the solid phase. The degree of interaction depends on the solute, the soil, and the flow regime. However, if there is little interaction, the solute can often be treated as a conservative tracer. Examples are tritium and, to a lesser degree, bromide. Other materials are only slightly soluble, readily react with the solid phase, or perhaps can change into alternative phases that are clearly non-conservative. In some cases, whether a solute can logically be considered as a conservative or non-conservative tracer depends on the time scale and where the process is occurring—for example, perhaps the reaction rates are low, and for a short time scale the process is conservative; alternatively, perhaps the reaction rate is driven by whether oxygen is available or whether a specific microbe or catalyst is present at a particular time and place. Most of the discussion is directed toward “miscible displacement” processes. For a miscible displacement process, the invading fluid mixes freely with the fluid that is being driven out. An example is the displacement of water of a concentration differing from that of the antecedent water. Miscible displacement of a low molecular weight alcohol with water is another example. Many problems of environmental concern are included, such as leaching of nitrates from the soil surface to the groundwater.

Keywords:   anion exclusion, breakthrough curves, conservative tracers, dispersivity, evapotranspiration, finite pulse solution, gas flow, immiscible displacement, miscible displacement

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .