Arsenate uptake, sequestration and reduction by a freshwater cyanobacterium: a potenial biologic control of arsenic in South Texas
| dc.contributor | Herbert, Bruce E. | |
| dc.creator | Markley, Christopher Thomas | |
| dc.date.accessioned | 2005-08-29T14:36:26Z | |
| dc.date.accessioned | 2017-04-07T19:49:59Z | |
| dc.date.available | 2005-08-29T14:36:26Z | |
| dc.date.available | 2017-04-07T19:49:59Z | |
| dc.date.created | 2003-05 | |
| dc.date.issued | 2005-08-29 | |
| dc.description.abstract | The toxicity and adverse health effects of arsenic are widely known. It is generally accepted that sorption/desorption reactions with oxy-hydroxide minerals (iron, manganese) control the fate and transport of inorganic arsenic in surface waters through adsorption and precipitation-dissolution processes. In terrestrial environments with limited reactive iron, recent data suggest organoarsenicals are potentially important components of the biogeochemical cycling of arsenic in near-surface environments. Elevated arsenic levels are common in South Texas from geogenic processes (weathering of As-containing rock units) and anthropogenic sources (a byproduct from decades of uranium mining). Sediments collected from South Texas show low reactive iron concentrations, undetectable in many areas, making oxy-hydroxide controls on arsenic unlikely. Studies have shown that eukaryotic algae isolated from arsenic-contaminated waters have increased tolerance to arsenate toxicity and the ability to uptake and biotransform arsenate. In this experiment, net uptake of arsenic over time by a freshwater cyanobacterium never previously exposed to arsenate was quantified as a function of increasing As concentrations and increasing N:P ratios. Toxic effects were not evident when comparing cyanobacterial growth, though extractions indicate accumulation of intracellular arsenic by the cyanobacterium. Increasing N:P ratios has minimal effect on net arsenate uptake over an 18 day period. However, cyanobacteria were shown to reduce arsenate at rates faster than the system can re-oxidize the arsenic suggesting gross arsenate uptake may be much higher. Widespread arsenate reduction by cyanobacterial blooms would increase arsenic mobility and potential toxicity and may be useful as a biomarker of arsenic exposure in oxic surface water environments. | |
| dc.identifier.uri | http://hdl.handle.net/1969.1/2235 | |
| dc.language.iso | en_US | |
| dc.publisher | Texas A&M University | |
| dc.subject | Arsenic | |
| dc.subject | Biotransformation | |
| dc.subject | Sequestration | |
| dc.subject | Cyanobacteria | |
| dc.title | Arsenate uptake, sequestration and reduction by a freshwater cyanobacterium: a potenial biologic control of arsenic in South Texas | |
| dc.type | Book | |
| dc.type | Thesis |