Economic and Environmental Geology

Table. 1.

Table. 1.

Sequential extraction process for arsenic in soil

Step Fraction Extractant Geochemical Mobility
1 Non-specifically sorbed (NH4)2SO4 High

Intermediate

Low
2 Specifically sorbed (NH4)H2PO4
3 Amorphous and poorly-crystaline hydrous oxides of Fe and Al NH4 oxaltate buffer (pH 3.25)
4 Well-crystallized hydrous oxides of Fe and Al NH4 oxalate buffer + ascorbic acid (pH 3.25)
5 Residual Aqua Regia
Econ. Environ. Geol. 2022;55:209-17 https://doi.org/10.9719/EEG.2022.55.2.209
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