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Arsenic in field‐collected soil solutions and extracts of contaminated soils and its implication to soil standards
Author(s) -
Wenzel Walter W.,
Brandstetter Anton,
Wutte Helmut,
Lombi Enzo,
Prohaska Thomas,
Stingeder Gerhard,
Adriano Domy C.
Publication year - 2002
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/1522-2624(200204)165:2<221::aid-jpln221>3.0.co;2-0
Subject(s) - arsenic , environmental chemistry , soil water , environmental science , contamination , soil contamination , soil science , chemistry , biology , ecology , organic chemistry
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 (As t ), 19.2 (0—726) for (NH 4 ) 2 C 2 O 4 ‐extractable (As o ), 2.35 (0—169) for (NH 4 ) 2 HPO 4 ‐extractable (As p ), and 0.143 (0—11.1) for (NH 4 ) 2 SO 4 ‐extractable (As s ) arsenic. Arsenic concentrations in soil solutions (As sol ) collected from organic surface layers and mineral horizons at five selected sites using suction cups fitted with nylon membranes ranged from 0 to 171 μg l —1 . Typically, the prevailing species of As in the soil solution was As(V). As sol was correlated with As s (As sol = 0.279 + 15.6 As s ; r 2 = 0.938; n = 17) and As t (As sol = 1.272 + 0.043 As t ; r 2 = 0.833; n = 17). Using these empirical models, As sol can be predicted quite accurately based on extraction with 0.05 M (NH 4 ) 2 SO 4 or total arsenic concentrations in the soil. Linking these models to drinking water standards (DWS) we propose soil standards for freshwater protection that vary for As s (mg kg —1 ) between 0.62 (for DWS = 10 μg l —1 WHO) and 3.19 (for DWS = 50 μg l —1 ). Corresponding standards for As t (mg kg —1 ) are 203 (DWS = 10 μg l —1 ) and 1133 (DWS = 50 μg l —1 ). These considerations demonstrate that changes in legislation on DWS may have dramatic impact on As concentrations in soil that are acceptable for groundwater protection.