Arsenic species in an arsenic hyperaccumulating fern, Pityrogramma calomelanos: a potential phytoremediator of arsenic-contaminated soils.
The fern Pityrogramma calomelanos is a hyperaccumulator of arsenic that grows readily on arsenic-contaminated soils in the Ron Phibun district of southern Thailand. P. calomelanos accumulates arsenic mostly in the fronds (up to 8350 microg As g(-1) dry mass) while the rhizoids contain the lowest concentrations of arsenic (88-310 microg As g(-1) dry mass). The arsenic species in aqueous extracts of the fern and soil were determined by high performance liquid chromatography coupled to an inductively coupled plasma mass spectrometer (HPLC-ICPMS) which served as an arsenic specific detector. Only a small part of the arsenic (6.1-12%) in soil was extracted into water, and most of this arsenic (> 97%) was present as arsenate. The arsenic in the fern rhizoids was approximately 60% water-extractable, 95% of which was present as arsenate. In contrast, arsenic in the fern fronds was readily extracted into water (86-93%) and was present mainly as arsenite (60-72%) with the remainder being arsenate. Methylarsonate and dimethylarsinate were detected as trace constituents in only two fern samples. Preliminary estimates of phytoremediation potential suggest that P. calomelanos might remove approximately 2% of the soil arsenic load per year. With due consideration to the type of arsenic compounds present in the fern, and their water-solubility, the option of disposing high arsenic ferns at sea is raised for discussion.
Francesconi
Kevin
K
Institute of Biology, University of Southern Denmark, Odense. kaf@biology.sdu.dk
Visoottiviseth
Pornsawan
P
Sridokchan
Weeraphan
W
Goessler
Walter
W
D001151:Arsenic / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics*; D015415:Biomarkers; D002851:Chromatography, High Pressure Liquid; D004787:Environmental Pollution / Q000517:prevention & control*; D029624:Ferns / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000493:pharmacokinetics*; D012995:Solubility; D014018:Tissue Distribution
D015415:Biomarkers; D012989:Soil Pollutants; D001151:Arsenic