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Coupling centrifuge modeling and laser ablation inductively coupled plasma mass spectrometry to determine contaminant retardation in clays

journal contribution
posted on 2009-01-01, 00:00 authored by Wendy TimmsWendy Timms, M Jim Hendry, Jason Muise, Robert Kerrich
Quantifying the retardation (Rd) of reactive solutes as they migrate through low-permeability clay-rich media is difficult, thus motivating this study to assess the viability of combining centrifuge modeling and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) techniques. An influent solution containing Cl-, trace metals, and lanthanide species flowed at 1.0 mL x h(-1) through an undisturbed clay-rich core sample (33 mm diameter x 50 mm long) mounted in a UFA Beckman centrifuge operating at 3000 rpm (N factor = 876 g). During the 87 day experiment the hydraulic conductivity of the core was 3.4 x 10(-10) m x s(-1). Effluent breakthrough data indicate the Rd of Tl to be 10; incomplete breakthrough (non-steady-state) data for 145Nd and 171Yb suggest Rd values of >75 and >85, respectively. At the completion of the transport experiment, longitudinal sections of the core solid were analyzed for 145Nd and 171Yb using a Cetac laser ablation system coupled with an ICP-MS. The longitudinal core sections yielded Rd values of >10000 for 145Nd and 171Yb. This study demonstrates coupling these techniques can provide Rd values for a wide range of reactive solutes with relatively rapid testing of small-scale, low hydraulic conductivity core samples.

History

Journal

Environmental Science & Technology

Volume

43

Pagination

1153-1159

Location

Washington, D.C.

ISSN

0013-936X

Language

eng

Publication classification

C Journal article, C1.1 Refereed article in a scholarly journal

Copyright notice

2009, American Chemical Society

Issue

4

Publisher

American Chemical Society