Arsenic K-edge X-ray absorption near-edge spectroscopy to determine oxidation states of arsenic of a coastal aquifer-aquitard system

Environ Pollut. 2013 Aug:179:160-6. doi: 10.1016/j.envpol.2013.04.005. Epub 2013 May 14.

Abstract

Determination of oxidation states of solid-phase arsenic in bulk sediments is a valuable step in the evaluation of its bioavailability and environmental fate in deposits, but is difficult when the sediments have low arsenic contents and heterogeneous distribution of arsenic species. As K-edge X-ray absorption near-edge spectroscopy (XANES) was used to determine quantitatively the oxidation states of arsenic in sediments collected from different depths of boreholes in the Pearl River Delta, China, where the highest aquatic arsenic concentration is 161.4 μg/L, but the highest solid arsenic content only 39.6 mg/kg. The results demonstrated that XANES is efficient in determining arsenic oxidation states of the sediments with low arsenic contents and multiple arsenic species. The study on the high-resolution vertical variations of arsenic oxidation states also indicated that these states are influenced strongly by groundwater activities. With the help of geochemical data, solid arsenic speciation, toxicity and availability were further discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arsenic / analysis*
  • China
  • Environmental Monitoring / methods*
  • Groundwater / chemistry*
  • Oxidation-Reduction
  • Water Pollutants, Chemical / analysis*
  • X-Ray Absorption Spectroscopy

Substances

  • Water Pollutants, Chemical
  • Arsenic