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November 2007 Newmont * Salazar Banco Fluoride Final- Report v 2 <br />times the concentration in the soil solution. Historically, annual alfalfa production at <br />Salazar Ranch averages 7 tons/ac with two harvest dates per growing season. If we <br />assume the fluoride concentration in the West Pit irrigation water (4.5 mg/1) is equal to the <br />concentration in the soil solution, then the maximum amount of fluoride accumulated and <br />removed by alfalfa per acre would be 13.5 mg/l or 1.89 lbs F/ac/year. <br />Calculation: <br />3 * 4.5 mg/1 F= 13.5 mg/l F <br />1 mg/1= 1 ppm and 1 ppm = 0.000001 % <br />13.5 ppm F / 1000000 = 0.000135 F <br />0.000135 * 14,000 lbs alfalfa/ac/year = 1.89 lbs F/ac/year <br />1.89 lbs/ac/year * 281 ac = 531.09 lbs F removed each year <br />FLUORIDE TOXICITY TO ALFALFA <br />The irrigation water that would be used at the Salazar Ranch does not pose any toxicity <br />problems for alfalfa. Using a plant accumulation factor of 3.0 and a safe tissue <br />concentration of 100 ppm (Kabata-Pendias 2001), a safe water level would be 33 ppm of <br />F (100 ppm _ 3.0). Since the amount of F in the irrigation water is only 4.5 ppm, there is <br />essentially no risk of reaching a toxicity threshold for alfalfa. <br />FLUORIDE TOXICITY TO DOMESTIC LIVESTOCK AND WILD UNGULATES <br />Assuming a worse case scenario where the irrigated alfalfa would provide the full ration <br />for domestic livestock or wild ungulates, such as deer and elk, the alfalfa would not pose a <br />fluoride toxicity problem for domestic or wild animals. The dietary safe level of F for <br />beef cattle is 40 ppm, 30 ppm for dairy cattle, 50 ppm for sheep, 60 ppm for horses, and <br />30 ppm for deer and elk (Shupe et al. 1972; Shupe et al. 1984). In order to reach toxicity <br />levels for beef cattle the F concentration in irrigation water would need to be at 10 ppm <br />(30 ppm tissue concentration - 3.0 BCF = 10 ppm). Using the same formula, the <br />irrigation water would need to have a F concentration of 16 ppm to pose a toxicity <br />MWH 1825 Sbarp Point Drive, Suite 118 *Fort Collins, Colorado 80525 * (970) 377-9410