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Downloaded by CALIFORNIA INST OF TECHNOLOGY on September 17, 2017 | http://pubs.acs.org Publication Date: October 30, 2002 | doi: 10.1021/bk-2003-0835.ch015
Total Arsenic in a Fishless Desert Spring: Montezuma Well, Arizona 1
Anne-Marie Compton-O'Brien , Richard D. Foust Michael E. Ketterer , and Dean W. Blinn 1
1,
Jr. *,
2
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Department of Chemistry and Merriam-Powell Center for Environmental Research and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86001-5698 2
Total arsenic was measured in various matrices from Montezuma Well, a unique ecosystem with many endemic species located in north-central Arizona, U.S.A. Montezuma Well water contains natural arsenic levels of 100 μg/L. Analysis was performed by nitric acid/hydrogen peroxide microwave digestion followed by quadrupole inductively coupled argon plasma mass spectrometry. Sediment, soil, Potamogeton illinoiensis roots, P. illinoiensis leaves, Berula erecta roots, B. erecta leaves, Fissidens grandifrons, Hyallela montezuma, H. azteca, Ranatra montezuma, Telebasis salva, Belostoma bakeri, Motobdella montezuma and DW-rinsed M. montezuma were collected and analyzed. Total arsenic values ranged from 1.0 to 2,810 μg/g (dw). Biodiminution of total arsenic in the littoral zone food web was observed. Total root arsenic levels were higher than leaf arsenic levels. Organisms show different mechanisms for coping with the elevated levels of arsenic found in the Well. The plants, inhibit vertical transport, others exclude arsenic and some absorb arsenic onto their surface in higher quantities than in their cells.
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© 2003 American Chemical Society Cai and Braids; Biogeochemistry of Environmentally Important Trace Elements ACS Symposium Series; American Chemical Society: Washington, DC, 2002.
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Introduction Few studies have tracked arsenic in freshwater food webs. A compilation of studies by Eisler (/) of field collected species of flora and fauna provides crucial information on dry weight (dw) and fresh weight (fw) of total arsenic in freshwater and marine organisms. However, the majority of the studies are for marine ecosystems; freshwater data mainly include fish and plants. The data frequently lack food web interactions. To date, there are only a few comprehensivefreshwaterfood web studies of arsenic (2-4). These studies show a biodiminution of arsenic in freshwater. This study is an attempt to provide information on afreshwaterfood web in the southwestern U.S.A. Montezuma Well is part of Montezuma Castle National Monument, located in north-central Arizona. It is a thermally constant, collapsed travertine spring, measuring 112 m in diameter with an average depth of 6.7 m (5). The Well contains naturally high concentrations of dissolved carbon dioxide (>450 mg/L), and is thus Ashless (6). Montezuma Well has very high levels of productivity. Productivity of phytoplankton is on the order of 602 gCm" yf ^d). The aquatic plant Potamogeton illinoiensis may grow up to 6 m in Montezuma Well, as compared to
