Modeling Phosphate Influence on Arsenate Reduction Kinetics by a Freshwater Cyanobacterium Academic Article uri icon


  • Arsenic speciation in natural surface-water systems can be highly impacted through biological processes that result in non-thermodynamically predicted species to dominate the system. In laboratory experiments, arsenate reduction by a freshwater cyanobacterium exhibited saturation kinetics increasingly inhibited by elevating solution phosphate concentrations. Approximately 100% arsenate reduction occurred by days 4, 7, and 10 in the low (0.35 m), middle (3. 5 m), and high (35 m) phosphate treatments, respectively, with maximum arsenate reduction rates ranged from 0.013 mol As g C-1 day-1 in the high-phosphate treatment to 0.398 mol As g C-1 day-1 in the low-phosphate treatment. Saturation kinetic models were utilized to evaluate the impact of cell growth and arsenate-phosphate uptake competition on arsenate reduction rates by the cyanobacterium. Results showed reduced arsenicals dominate arsenic speciation once growth reached steady state, indicating reduced arsenicals may dominate natural systems, even when considering conservatively high, abiotic arsenic reoxidation. 2009 Springer Science+Business Media B.V.

published proceedings


author list (cited authors)

  • Markley, C. T., & Herbert, B. E.

citation count

  • 19

complete list of authors

  • Markley, Christopher T||Herbert, Bruce E

publication date

  • January 2010