TY - JOUR
T1 - Hydrogel-encapsulated soil
T2 - A tool to measure contaminant attenuation in situ
AU - Spalding, Brian P.
AU - Brooks, Scott C.
AU - Watson, David B.
PY - 2010/4/15
Y1 - 2010/4/15
N2 - Hydrogel encapsulation presents a novel and powerful general method to observe many water?solid contaminant interactions in situ for a variety of aqueous media including groundwater, with a variety of nondestructive analytical methods, and with a variety of solids including contaminated soil. After intervals of groundwater immersion, polyacrylamide hydrogel-encapsulated solid specimens were retrieved, assayed nondestructively for uranium and other elements using X-ray fluorescence spectroscopy, and replaced in groundwater for continued reaction. Desorption dynamics of uranium from contaminated soils and other solids, when moved to uncontaminated groundwater, were fit to a general two-component kinetic retention model with slow-release and fast-release fractions for the total uranium. In a group of Oak Ridge soils with varying ambient uranium contamination (169?1360 mg/kg), the uranium fraction retained under long-term in situ kinetic behavior was strongly correlated (r2 = 0.89) with residual uranium after laboratory sequential extraction of water-soluble and cation-exchangeable fractions of the soils. To illustrate how potential remedial techniques can be compared to natural attenuation, thermal stabilization of one soil increased the size of its long-term in situ retained fraction from 50% to 88% of the total uranium and increased the half-life of that long-term retained fraction from 990 to 40000 days.
AB - Hydrogel encapsulation presents a novel and powerful general method to observe many water?solid contaminant interactions in situ for a variety of aqueous media including groundwater, with a variety of nondestructive analytical methods, and with a variety of solids including contaminated soil. After intervals of groundwater immersion, polyacrylamide hydrogel-encapsulated solid specimens were retrieved, assayed nondestructively for uranium and other elements using X-ray fluorescence spectroscopy, and replaced in groundwater for continued reaction. Desorption dynamics of uranium from contaminated soils and other solids, when moved to uncontaminated groundwater, were fit to a general two-component kinetic retention model with slow-release and fast-release fractions for the total uranium. In a group of Oak Ridge soils with varying ambient uranium contamination (169?1360 mg/kg), the uranium fraction retained under long-term in situ kinetic behavior was strongly correlated (r2 = 0.89) with residual uranium after laboratory sequential extraction of water-soluble and cation-exchangeable fractions of the soils. To illustrate how potential remedial techniques can be compared to natural attenuation, thermal stabilization of one soil increased the size of its long-term in situ retained fraction from 50% to 88% of the total uranium and increased the half-life of that long-term retained fraction from 990 to 40000 days.
UR - http://www.scopus.com/inward/record.url?scp=77950941695&partnerID=8YFLogxK
U2 - 10.1021/es903983f
DO - 10.1021/es903983f
M3 - Article
C2 - 20230051
AN - SCOPUS:77950941695
SN - 0013-936X
VL - 44
SP - 3047
EP - 3051
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 8
ER -
