1 / 10

Microbial Anoxic Oxidation of Arsenite: Health Implications & Environmental Impact

Discover the potential health effects and environmental consequences of arsenic contamination, focusing on microbial anoxic oxidation processes. Explore redox cycles of arsenic and iron, their interaction in bioreactors, and the efficiency of microbial oxidation for arsenic removal.

chaman
Download Presentation

Microbial Anoxic Oxidation of Arsenite: Health Implications & Environmental Impact

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Microbial Anoxic Oxidation of Arsenite Lily Milner Chemical and Environmental Engineering, The University of Arizona 4/19/08 Acknowledgements: Dr. Reyes Sierra, Dr. Jim Field, Alex Sun, Estephania Marcos

  2. Health Effects Skin Lesions Lung, Kidney Cancer Diabetes Cardiovascular Disease Arsenic Federal standard for Arsenic in drinking water : 10 microgram/L • Inorganic Sources • Wood Treatment • Pesticides • Medicines • Mining • Organic Sources • Volcanic Activity • Sea Organisms • Weathering of Rocks

  3. Arsenic Contamination in the US http://www.usgs.org

  4. Two Common Species of Arsenic Found in The Environment Arsenite [As(III)] OH—As—OH | OH • More Toxic • Absorbs to few minerals • Prevalent in anaerobic environments Arsenate [As(V)] O | | HO-As-OH | OH • Less Toxic • Absorbs to many minerals • Prevalent in aerobic environments

  5. Redox Cycles of Arsenic and Iron & Their Interaction As(III) Oxidation e--acceptor (O2 , NO3-) e—donor (organic matter) As(V) Reduction Fe(II) Oxidation e--acceptor (O2 , NO3 -) e--donor Fe(III) Reduction As(V) As(V) As(III) As(V) Fe(III) Oxides Fe(II) + As(V) As(V) As(V)

  6. Microbial Process of Bioreactors 5 H3AsO3 + 2 NO3-  5 HAsO4-2 + N2 + 8H+ + H2O Influent • Electron Donor • 6.67e-3 mM As(III) • 0.357 mM Fe(II) • Electron Acceptor • 2.5 mM NO3- • Carbon Source • HCO3- Sand Bed Gas Effluent Influent

  7. SF1 Reactor with As(III)/Fe(II) + nitrate SF2 Control reactor with As(III)/Fe(II) – No nitrate

  8. Results For Iron Oxidation

  9. Results for Arsenic Removal

  10. Conclusions • The microbial oxidation of Fe(II) and As(III) to Fe(III) and As(V) by chemolithotrophic denitrifiers can account for the difference in arsenic removal between the columns. • The results show that microbial oxidation of Fe(II) and As(III) linked to denitrification decreases the environmental mobility of arsenic.

More Related