Arsenic in field-collected soil solutions and extracts of contaminated soils and its implication to soil standards
Walter W. Wenzel1, Anton Brandstetter1, Helmut Wutte1,
Enzo Lombi2, Thomas Prohaska3, Gerhard Stingeder3,
and Domy C. Adriano4
1Institute of Soil Science, University of Agricultural Sciences
Vienna -BOKU, Gregor Mendel StraBe 33, A-1180 Vienna, Austria
2Soil Science Department, IACR-Rothamsted, Harpenden, AL5 2JQ
Herts, UK
3Institute of Chemistry, University of Agricultural Sciences
Vienna -BaKU, Muthgasse 18, A-1190 Vienna, Austria
4Savannah River Ecology Laboratory, The University of Georgia,
Athens, Drawer E, Aiken, SC, 29801 U.S.A.
Accepted 23 January 2002
Summary - Zusammenfassung
Large concentrations of arsenic in soils, sediments, and freshwaters require
risk assessment across the Central Alps and other regions. We measured
arsenic concentrations in soil samples collected from 38 sites located
in the Austrian Central Alps that had been contaminated due to mining
and smelter activities and geogenic mineralization. Medians and ranges
of arsenic concentrations (in mg kg-1) in the soil solid phase
were 77.1 (1-3000) for the total (Ast), 19.2 (0-726) for (NH4)2C2O4-extractable
(Aso), 2.35 (0-169) for (NH4)2HPO4-extractable
(Asp), and 0.143 (0-11.1) for (NH4)2HPO4-extractable
(Ass), arsenic. Arsenic concentrations in soil solutions (ASsol)
collected from organic surface layers and mineral horizons at five selected
sites using suction cups fitted with nylon membranes ranged from 0 to
171 uµg 1-1. Typically, the prevailing species of As
in the soil solution was As(V). ASsol was correlated with ASs
(ASsol = 0.279 + 15.6 ASs; r2=0.938;
n=17) and AS (ASsol = 1.272 + 0.043 ASt; r2
= 0.833; n=17). Using these empirical models. ASsol can be
predicted quite accurately based on extraction with 0.05M (NH4)2SO4
or toal arsenic concentrations in the soil. Linking these models to drinking
water standards (DWS) we propose soil standards for freshwater protection
that vary for ASs (mg kg-1) between 0.62 (for DWS
= 10µg1-1 WHO) and 3.19 (for DWS = 50 uµg1-1).
Corresponding standards for ASt (mg kg-1) are 203
(DWS = 10 µg 1-1) and 1133 (DWS = 50 uµg 1-1).
These considerations demonstrate that changes in legislation on DWS may
have dramatic impact on As concentrations in soil that ware acceptable
for groundwater protection.
Key Words: arsenic / soil solution / soil standards / soil contamination
SREL Reprint #2747
Wenzel, W. W., A. Brandstetter, H. Wutte, E. Lombi, T. Prohaska, G. Stingeder and D. C. Adriano. 2002. Arsenic in field-collected soil solutions and extracts of contaminated soils and its implication to soil standards. Journal of Nutrition Soil Science 165:221-228.
