|
Anne-Marie
Compton
Student Watershed
Research Award Recipient
Anne-Marie
Compton is a graduate student in the department of chemistry at Northern
Arizona University. She is
working under the advisorship of Dr. Richard Foust, professor of
environmental analytical chemistry at NAU.
Her other committee members include: Dr. Michael Ketterer,
professor of analytical chemistry at NAU; Dr. Dean Blinn, professor of
biology at NAU and Dr. David Velinsky, environmental geochemist at the
Academy of Natural Sciences in Philadelphia, PA.
Her research involves looking at the biogeochemical cycling of
arsenic in Montezuma Well Arizona. She
anticipates graduation in December 2001.
An article explaining her research was printed in the Arizona Daily
Sun on May 9, 2001 written by Anne Minard.
In
addition to being a recipient of a research grant for the Verde Watershed
and Education Program, Ms. Compton is also the recipient of the American
Chemical Society's Environmental Chemistry Division Graduate Student Award
for the year 2001 as well as a Merriam-Powell Center for Sustainable
Environments Fellow.
Montezuma
Well is part of Montezuma Castle National Monument and is located in the
Verde River Watershed. For
more information on Montezuma Well, go to:
http://ag.arizona.edu/AZWATER/awr/septoct01/specproj.html
Benefits to
residents of Verde Valley:
Natural groundwater arsenic levels in the Verde Valley range from 10
to over 100 g/L, presenting a significant health threat to people who
drink this water. Through a better understanding of the behavior of
natural ground water arsenic it will be possible to tailor water treatment
processes to the needs of Verde Valley communities.
What was
learned:
Groundwater arsenic in the Verde Valley enters the aquifer near
Montezuma Well, and most likely comes from water that has contacted the
Supi and Verde formations. The Clarkdale mine tailings do not appear to
contribute significantly to groundwater arsenic. Arsenic enters Montezuma
Well (the location with highest arsenic levels) as a mixture of two
inorganic arsenic species, arsenate (As +5) and arsenite (As +3). Arsenite
is the most toxic form of arsenic. The high dissolved oxygen levels in
Montezuma Well oxidize all dissolved arsenic to the +5 oxidation state
(arsenate). Algae and plants ingest arsenate through the phosphorous
uptake mechanism, and metabolize the arsenic to an As(III)-glutathione
complex, mono-methyl and di-methyl arsenic acids, and arsenic sugar
complexes. The metabolized arsenic products are significantly less toxic
than arsenate and arsenite, the inorganic arsenic forms present in
groundwater.
Papers
published from this research:
“Surface water and Groundwater Arsenic Concentrations in the Verde Valley
in Central Arizona,” R. D. Foust, Jr., P. Mohapatra, A. M. Compton and J.
Reifel, Applied Geochemistry,19 (2004) 251-255.
“Biogeochemical Transformations of Arsenic in Montezuma Well, Arizona: A
Model Study for the Behavior of Arsenic in the Environment,” R. D. Foust,
Jr., M. S. Costanza-Robinson, A. M. Compton-O’Brien, R. C. Prince, I. J.
Pickering and G. N. George, Proc. 7th Intern. Conf. on the Biogeochem. Of
Trace Elements, Upsala, Sweden, 2003, pp. 20-21.
“Total Arsenic
in a Fishless Desert Spring: Montezuam Well, Arizona,” A. M.
Compton-O’Brien, R. D. Foust, Jr., M. E. Ketterer and D. W. Blinn, In
Biogeochemistry of Environmentally Important Trace Elements, Y. Cai and O.
C. Braids, Eds., ACS Symposium Series 385, American Chemical Society,
Washington, DC, 2003, pp 200-209.
|
