Extraction, Speciation, and Analysis of Arsenic and Arsenical Herbicides in Runoff: Evaluation of Simple Methods at the ppb Level1
- R. D. Wauchope and
- M. Yamamoto2
The use of a column chromatographic technique for separation of inorganic arsenic (As) from methyl- and dimethyl-derivatives, and flameless atomic absorption technique for quantitating the separated As species at the ppb level, have been evaluated for use in studies of the behavior of arsenate and methanearsonate (CH3AsO32-) ions in runoff (water and suspended sediment). The former ion is a natural component of soils. The latter ion is extensively used as an herbicide in the sodium and disodium salt forms, commonly called MSMA and DSMA, respectively. Runoff from two watersheds was spiked with 200 ppb As as arsenate or 189 ppb As as methanearsonate, or both. The partitioning of the As between sediment and water phases was measured and the As species in both phases were identified and quantitated. Recoveries ranged from 80 to 100%, and relative precision between samples averaged 10% for As concentrations between 10 and 200 ppb. In the partitioning of the added As between sediment and water phases of the runoff, arsenate appears to be much more strongly adsorbed by sediments than in methanearsonate. Although both speciation and quantitation techniques are relatively simple, they will be adequate for exploratory studies on arsenate and methanearsonate behavior in runoff and impoundments.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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