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Arsenic and antimony species in the terrestrial environment

University of British Columbia

The determination of arsenic and antimony species in environmental samples can be used to assist in toxicity assessment, as well as to yield information about environmental processes. Such information about samples from the terrestrial environment was sought. Existing methods for speciation were adapted, including high-performance liquid chromatography (HPLC) coupled with inductively coupled plasma-mass spectrometry (ICP-MS), for the determination of both arsenic and antimony species, and hydride generation-gas chromatography (HG-GC) with atomic absorption spectrometric (AAS) detection and mass spectrometric (MS) detection, for the determination of antimony species. Arsenate, when added to mycelial cultures of Scleroderma citrinum and Macrolepiotaprocera, was reduced to arsenite, but no further processes (i.e., methylation or formation of arsenosugars or arsenobetaine) were observed. This may indicate that the presence of more complex arsenicals in environmental mushroom specimens is dependent on symbiotic interactions between the fungus and its surroundings, rather than resulting from independent synthesis by the fungus. Pleurotus flabellatus oxidized antimony (III) to antimonate (Sb(OH)6), and formed an antimony-containing metabolite of unknown identity. Water soluble arsenic species were determined in a host of terrestrial and freshwater biota from a hot springs environment (Meager Creek, BC) and from an area impacted by mining and smelting activities (Yellowknife, NWT). Arsenate and arsenite (the more toxic forms of arsenic) were the predominant species extracted from plants, mosses, microbial mats, algae and lichens. Small amounts of arsenosugars and methylated arsenic were detected as well. Arsenobetaine was discovered for the first time in lichens, and it was also the major form of arsenic in freshwater fish. The majority of detectable arsenic in freshwater mussels and snails was as arsenosugars and the tetramethylarsonium ion, respectively. Large amounts of arsenic, of an unknown toxicological and chemical nature, remained unextracted or undetected in all samples. A dimethylantimony compound was found in moss samples from Yellowknife, confirming that methylation of antimony takes place in the environment.

Thesis/Dissertation

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2009-06-22

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http://hdl.handle.net/2429/9520

Chemistry

University of British Columbia

UBCV

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