Details
| Original language | English |
|---|---|
| Title of host publication | Trace Elements in Soil |
| Subtitle of host publication | Bioavailability, Flux, and Transfer |
| Pages | 229-245 |
| Number of pages | 17 |
| ISBN (electronic) | 9781420032734 |
| Publication status | Published - 1 Jan 2001 |
Abstract
To predict the cadmium concentrations of soil solutions CCd under varying properties of soil matrix and electrolyte, we established Cd sorption isotherms for 225 samples from sandy, northern German arable and forest soils, and from these derived the Freundlich parameters k and M. Standard electrolyte was 5 mM Ca(NO3)2. As the initially (native) sorbed fraction of Cd, we used the amount extracted with 0.025 M Na2-EDTA at 20ºC, 2 h shaking. The average value of parameter Mwas 0.815 (). There was some correlation of M with pH: samples above pH 6 had an average M of just 0.730. The maininformation about the sorption properties of the soils was contained in k, which could be predicted by multiple regressions from pH, organic carbon (OC,%) and clay content (%) for one subset of Ap horizons (r2 0.96). When all 225 samples were combined, no more statistical influence was found for the variable “clay” on the multiple regression models. Clay, therefore, is not included in the final model in which Freundlich k (mg1M LM kg1) is given by 0.993pH0.537 OC0.783. The resulting values are valid for 5 mM Ca(NO3)2, 20ºC and were used, together with the mean M of 0.815 and the Freundlich equation, topredict the Cd concentrations of the soil solutions (CCd) of the 225 investigatedsites, both for the current load of Cdand assuming higher contamination. In a large number of samples, the estimated CCd exceeded current drinking water threshold values and other solution–based critical limits when a total load of 1 mg Cd kg−1 soil was assumed. In a final step, we corrected the predicted CCd for the strength of the electrolyte, here defined by the Ca2 concentration, and the proportion of the complexing Cl among the accompanying anions. The approach appears to be promising, but there are still some clear deficiencies concerning the prediction of the Freundlich exponent M andtheinfluence on k of the independent variables DOC, time, and temperature on the one hand, and the contents of clay or oxides on the other.
ASJC Scopus subject areas
- Engineering(all)
- General Engineering
- Agricultural and Biological Sciences(all)
- General Agricultural and Biological Sciences
- Chemistry(all)
- General Chemistry
- Environmental Science(all)
- General Environmental Science
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Trace Elements in Soil: Bioavailability, Flux, and Transfer. 2001. p. 229-245.
Research output: Chapter in book/report/conference proceeding › Contribution to book/anthology › Research › peer review
}
TY - CHAP
T1 - Quality of estimated freundlich parameters of cd sorption from pedotransfer functions to predict cadmium concentrations of soil solution
AU - Springob, Günther
AU - Tetzlaff, Dörthe
AU - Schön, Angela
AU - Böttcher, Jürgen
N1 - Publisher Copyright: © 2001 by Taylor & Francis Group, LLC. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2001/1/1
Y1 - 2001/1/1
N2 - To predict the cadmium concentrations of soil solutions CCd under varying properties of soil matrix and electrolyte, we established Cd sorption isotherms for 225 samples from sandy, northern German arable and forest soils, and from these derived the Freundlich parameters k and M. Standard electrolyte was 5 mM Ca(NO3)2. As the initially (native) sorbed fraction of Cd, we used the amount extracted with 0.025 M Na2-EDTA at 20ºC, 2 h shaking. The average value of parameter Mwas 0.815 (). There was some correlation of M with pH: samples above pH 6 had an average M of just 0.730. The maininformation about the sorption properties of the soils was contained in k, which could be predicted by multiple regressions from pH, organic carbon (OC,%) and clay content (%) for one subset of Ap horizons (r2 0.96). When all 225 samples were combined, no more statistical influence was found for the variable “clay” on the multiple regression models. Clay, therefore, is not included in the final model in which Freundlich k (mg1M LM kg1) is given by 0.993pH0.537 OC0.783. The resulting values are valid for 5 mM Ca(NO3)2, 20ºC and were used, together with the mean M of 0.815 and the Freundlich equation, topredict the Cd concentrations of the soil solutions (CCd) of the 225 investigatedsites, both for the current load of Cdand assuming higher contamination. In a large number of samples, the estimated CCd exceeded current drinking water threshold values and other solution–based critical limits when a total load of 1 mg Cd kg−1 soil was assumed. In a final step, we corrected the predicted CCd for the strength of the electrolyte, here defined by the Ca2 concentration, and the proportion of the complexing Cl among the accompanying anions. The approach appears to be promising, but there are still some clear deficiencies concerning the prediction of the Freundlich exponent M andtheinfluence on k of the independent variables DOC, time, and temperature on the one hand, and the contents of clay or oxides on the other.
AB - To predict the cadmium concentrations of soil solutions CCd under varying properties of soil matrix and electrolyte, we established Cd sorption isotherms for 225 samples from sandy, northern German arable and forest soils, and from these derived the Freundlich parameters k and M. Standard electrolyte was 5 mM Ca(NO3)2. As the initially (native) sorbed fraction of Cd, we used the amount extracted with 0.025 M Na2-EDTA at 20ºC, 2 h shaking. The average value of parameter Mwas 0.815 (). There was some correlation of M with pH: samples above pH 6 had an average M of just 0.730. The maininformation about the sorption properties of the soils was contained in k, which could be predicted by multiple regressions from pH, organic carbon (OC,%) and clay content (%) for one subset of Ap horizons (r2 0.96). When all 225 samples were combined, no more statistical influence was found for the variable “clay” on the multiple regression models. Clay, therefore, is not included in the final model in which Freundlich k (mg1M LM kg1) is given by 0.993pH0.537 OC0.783. The resulting values are valid for 5 mM Ca(NO3)2, 20ºC and were used, together with the mean M of 0.815 and the Freundlich equation, topredict the Cd concentrations of the soil solutions (CCd) of the 225 investigatedsites, both for the current load of Cdand assuming higher contamination. In a large number of samples, the estimated CCd exceeded current drinking water threshold values and other solution–based critical limits when a total load of 1 mg Cd kg−1 soil was assumed. In a final step, we corrected the predicted CCd for the strength of the electrolyte, here defined by the Ca2 concentration, and the proportion of the complexing Cl among the accompanying anions. The approach appears to be promising, but there are still some clear deficiencies concerning the prediction of the Freundlich exponent M andtheinfluence on k of the independent variables DOC, time, and temperature on the one hand, and the contents of clay or oxides on the other.
UR - http://www.scopus.com/inward/record.url?scp=33845216681&partnerID=8YFLogxK
M3 - Contribution to book/anthology
AN - SCOPUS:33845216681
SN - 9781566705073
SP - 229
EP - 245
BT - Trace Elements in Soil
ER -