Organoarsenic compounds in plants and soil on top of an ore vein

Abstract

AbstractPlants and soil collected above an ore vein in Gasen (Austria) were investigated for total arsenic concentrations by inductively coupled plasma mass spectrometry (ICP‐MS). Total arsenic concentrations in all samples were higher than those usually found at non‐contaminated sites. The arsenic concentration in the soil ranged from ∼700 to ∼4000 mg kg−1 dry mass. Arsenic concentrations in plant samples ranged from ∼0.5 to 6 mg kg−1 dry mass and varied with plant species and plant part. Examination of plant and soil extracts by high‐performance liquid chromatography–ICP‐MS revealed that only small amounts of arsenic (<1%) could be extracted from the soil and the main part of the extractable arsenic from soil was inorganic arsenic, dominated by arsenate. Trimethylarsine oxide and arsenobetaine were also detected as minor compounds in soil. The extracts of the plants (Trifolium pratense, Dactylis glomerata, and Plantago lanceolata) contained arsenate, arsenite, methylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, the tetramethylarsonium ion, arsenobetaine, and arsenocholine (2.5–12% extraction efficiency). The arsenic compounds and their concentrations differed with plant species. The extracts of D. glomerata and P. lanceolata contained mainly inorganic arsenic compounds typical of most other plants. T. pratense, on the other hand, contained mainly organic arsenicals and the major compound was methylarsonic acid. Copyright © 2002 John Wiley & Sons, Ltd.