Evaluation of Active Cap Materials for Metal Retention in Sediments

Anna Sophia Knox, Michael Huntz Paller, Kenneth Lamar Dixon

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This study evaluated chemically active amendments used to construct active caps for remediating contaminated sediments. Three experiments assessed the effects of apatite, organoclay, zeolite, and biopolymers (chitosan and xanthan) on metal mobility, retention, and speciation. The first showed that the amendments individually and in mixtures (2 percent dry weight) reduced the concentrations of Cr, Co, Ni, and Pb in water extracts from reduced sediment. The second experiment, which used sequential extraction procedures to evaluate the effects of the amendments on metal speciation, showed that the amendments reduced the potentially mobile fractions of Pb, Zn, Ni, Cr, and Cd that are likely to be bioavailable. Last, column studies showed that active caps composed of the amendments prevented the diffusive transport of metals from contaminated sediment over six months. In addition, there was a "zone of influence" beneath the caps in which water extractable concentrations of metals declined substantially compared with untreated sediment.

Original languageEnglish (US)
Pages (from-to)49-69
Number of pages21
Issue number3
StatePublished - 2014
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Engineering
  • Waste Management and Disposal
  • Pollution


Dive into the research topics of 'Evaluation of Active Cap Materials for Metal Retention in Sediments'. Together they form a unique fingerprint.

Cite this