TY - JOUR
T1 - Using nitrogen and carbon dioxide molecules to probe arsenic(V) bioaccessibility in soils
AU - Makris, Konstantinos C.
AU - Sarkar, Dibyendu
AU - Datta, Rupali
AU - Ravikovitch, Peter I.
AU - Neimark, Alexander V.
PY - 2006/12/15
Y1 - 2006/12/15
N2 - Highly specialized personnel and high cost are typically required for in vivo risk assessment of arsenic (As) exposure to humans in As-contaminated soils. Arsenic bioaccessibility in soils, as determined with the aid of in vitro tests, is quite variable, and its magnitude depends upon unidentified soil properties. Use of soil chemical properties is a common practice for construction of As(V) sorption and bioaccessibility models with relative success. We propose a novel As(V) bioaccessibility model, which was tested on 17 soils. The model includes only two parameters characterizing surface properties of soils that are readily determined from N2- and CO 2-based specific surface areas (SSAs), and total organic carbon (OC) content. We found that N2 and CO2 molecules act as As(V) "surrogates", probing easily accessible and relatively difficult to access soil porosity, respectively. Three interrelated linear models were constructed using two terms (CO2/N2-based SSAs and OC) that were significant (p < 0.001) in explaining 51 and 95% of the variability observed in As(V) sorption and bioaccessibility, respectively. The proposed models successfully predicted bioaccessible As concentrations for 4 out of the 5 soils that were not included in the bioaccessibility models, reaching RMSE values of ≤ 10%.
AB - Highly specialized personnel and high cost are typically required for in vivo risk assessment of arsenic (As) exposure to humans in As-contaminated soils. Arsenic bioaccessibility in soils, as determined with the aid of in vitro tests, is quite variable, and its magnitude depends upon unidentified soil properties. Use of soil chemical properties is a common practice for construction of As(V) sorption and bioaccessibility models with relative success. We propose a novel As(V) bioaccessibility model, which was tested on 17 soils. The model includes only two parameters characterizing surface properties of soils that are readily determined from N2- and CO 2-based specific surface areas (SSAs), and total organic carbon (OC) content. We found that N2 and CO2 molecules act as As(V) "surrogates", probing easily accessible and relatively difficult to access soil porosity, respectively. Three interrelated linear models were constructed using two terms (CO2/N2-based SSAs and OC) that were significant (p < 0.001) in explaining 51 and 95% of the variability observed in As(V) sorption and bioaccessibility, respectively. The proposed models successfully predicted bioaccessible As concentrations for 4 out of the 5 soils that were not included in the bioaccessibility models, reaching RMSE values of ≤ 10%.
UR - http://www.scopus.com/inward/record.url?scp=33845765356&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33845765356&partnerID=8YFLogxK
U2 - 10.1021/es061227i
DO - 10.1021/es061227i
M3 - Article
C2 - 17256520
AN - SCOPUS:33845765356
SN - 0013-936X
VL - 40
SP - 7732
EP - 7738
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 24
ER -