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Title: Laboratory and field scale evaluation of geochemical controls on groundwater transport of nitroaromatic ammunition residues

Abstract

Sorption to soils and sediments of nitroaromatic explosives may be due to interactions with natural organic matter (NOM) or complex formation with clays, which strongly depends on the type of exchangeable cations, i.e., the base saturation of the clays. The authors examined the relative importance of these two processes for NAC sorption at aquifer material and evaluated the potential of decreasing or enhancing the mobility of NACs in contaminated aquifers by stimulated cation exchange. Generally, sorption on NOM of 2,4,6-trinitrotoluene (TNT) and related nitroaromatic compounds (NACs) was low compared to sorption at clays, and no evidence for specific interactions with NOM was found. Adsorbed NOM hardly affected the complex formation of NACs with clays. NAC sorption at pure clays and at aquifer material depended on the K[sup +]-saturation of these materials. Typical aquifer material containing [le]1% NOM and 3-5% clays exhibited similar sorption features than pure clay minerals, suggesting that NAC sorption to the bulk aquifer matrix was dominated by complex formation with clays. They applied these laboratory findings in a two-step field test designed to control the groundwater transport of NACs by the injection of electrolytes. 4-Nitrotoluene (4-NT) and KCI were injected into a sandy aquifer, and their groundwatermore » transport was monitored at an extraction well. Subsequent injection of CaCl[sub 2] remobilized the previously adsorbed 4-NT due to ion exchange of Ca[sup 2+] for K[sup +] at clays present in the aquifer matrix. The susceptibility of NAC sorption to the composition of exchangeable cations at clays was confirmed for TNT and related NACs. Controlling the base saturation of the aquifer matrix by electrolyte injections thus opens new perspectives for gentle remediation of sites contaminated with nitroaromatic explosives.« less

Authors:
; ;  [1];  [2]
  1. Swiss Federal Inst. of Technology, Duebendorf (Switzerland)
  2. Dresdner Grundwasserforschungszentrum e.V., Dresden (Germany)
Publication Date:
OSTI Identifier:
6299142
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 33:15; Journal ID: ISSN 0013-936X
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; BENCH-SCALE EXPERIMENTS; ENVIRONMENTAL TRANSPORT; FIELD TESTS; GEOCHEMISTRY; GROUND WATER; NITRO COMPOUNDS; REMEDIAL ACTION; RESIDUES; TNT; WATER POLLUTION; CHEMICAL EXPLOSIVES; CHEMISTRY; EXPLOSIVES; HYDROGEN COMPOUNDS; MASS TRANSFER; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; OXYGEN COMPOUNDS; POLLUTION; TESTING; WATER; 540220* - Environment, Terrestrial- Chemicals Monitoring & Transport- (1990-); 450100 - Military Technology, Weaponry, & National Defense- Chemical Explosions & Explosives

Citation Formats

Weissmahr, K W, Schwarzenbach, R P, Haderlein, S B, and Hildenbrand, M. Laboratory and field scale evaluation of geochemical controls on groundwater transport of nitroaromatic ammunition residues. United States: N. p., 1999. Web. doi:10.1021/es981107d.
Weissmahr, K W, Schwarzenbach, R P, Haderlein, S B, & Hildenbrand, M. Laboratory and field scale evaluation of geochemical controls on groundwater transport of nitroaromatic ammunition residues. United States. https://doi.org/10.1021/es981107d
Weissmahr, K W, Schwarzenbach, R P, Haderlein, S B, and Hildenbrand, M. 1999. "Laboratory and field scale evaluation of geochemical controls on groundwater transport of nitroaromatic ammunition residues". United States. https://doi.org/10.1021/es981107d.
@article{osti_6299142,
title = {Laboratory and field scale evaluation of geochemical controls on groundwater transport of nitroaromatic ammunition residues},
author = {Weissmahr, K W and Schwarzenbach, R P and Haderlein, S B and Hildenbrand, M},
abstractNote = {Sorption to soils and sediments of nitroaromatic explosives may be due to interactions with natural organic matter (NOM) or complex formation with clays, which strongly depends on the type of exchangeable cations, i.e., the base saturation of the clays. The authors examined the relative importance of these two processes for NAC sorption at aquifer material and evaluated the potential of decreasing or enhancing the mobility of NACs in contaminated aquifers by stimulated cation exchange. Generally, sorption on NOM of 2,4,6-trinitrotoluene (TNT) and related nitroaromatic compounds (NACs) was low compared to sorption at clays, and no evidence for specific interactions with NOM was found. Adsorbed NOM hardly affected the complex formation of NACs with clays. NAC sorption at pure clays and at aquifer material depended on the K[sup +]-saturation of these materials. Typical aquifer material containing [le]1% NOM and 3-5% clays exhibited similar sorption features than pure clay minerals, suggesting that NAC sorption to the bulk aquifer matrix was dominated by complex formation with clays. They applied these laboratory findings in a two-step field test designed to control the groundwater transport of NACs by the injection of electrolytes. 4-Nitrotoluene (4-NT) and KCI were injected into a sandy aquifer, and their groundwater transport was monitored at an extraction well. Subsequent injection of CaCl[sub 2] remobilized the previously adsorbed 4-NT due to ion exchange of Ca[sup 2+] for K[sup +] at clays present in the aquifer matrix. The susceptibility of NAC sorption to the composition of exchangeable cations at clays was confirmed for TNT and related NACs. Controlling the base saturation of the aquifer matrix by electrolyte injections thus opens new perspectives for gentle remediation of sites contaminated with nitroaromatic explosives.},
doi = {10.1021/es981107d},
url = {https://www.osti.gov/biblio/6299142}, journal = {Environmental Science and Technology},
issn = {0013-936X},
number = ,
volume = 33:15,
place = {United States},
year = {Sun Aug 01 00:00:00 EDT 1999},
month = {Sun Aug 01 00:00:00 EDT 1999}
}