LEVELS OF VARIOUS ELEMENTS OF CONCERN IN FEED PHOSPHATES OF DOMESTIC AND FOREIGN ORIGIN

Thirty-six feed phosphates, including nine mono-dicalcium phosphates ( M-DCP, 21% P), 13 di-monocalcium phosphates (D-MCP, 18.5% P), and 14 t hermochemically produced defluorinated phosphates (DFP, 18.0% P), were analyzed for moisture, Ca, P, and 9 essential minerals (K, Mg, Na, Cl , Fe, Cu, Mn, Se, and Zn). Also, nine potentially toxic elements (Al, F, As, Cd, Cr, Hg, Pb, Ni, and V) were determined. All of the M-DCP we re of domestic origin; 5 of the 13 D-MCP samples were obtained in Alge ria, Peru, Holland, and South Africa. The DFP samples included 10 dome stic products, 2 samples from Russia, 1 from Poland, and 1 from Japan. Levels of Na were high in the DFP samples (3.96 to 5.78%), except for the two Russian samples, which contained only .16 and .19%. Magnesium levels varied from .09 to .76%,.02 to 1.21%, and .01 to 1.54% in the M-DCP, D-MCP, and DFP samples, respectively. Two Russian DFP samples c ontained 1.51 and 1.54% Mg. Chlorine levels were generally quite low ( .002 to .020%); however, two precipitated D-MCP samples contained .12 and 1.47% Cl. Iron levels were high (.24 to 1.41%) in all samples exce pt the bone-precipitated D-MCP (.039%), and the reference standard, ca lcium phosphate, dibasic dihydrate, USP (.029%). Levels of Cu, Mn, and Zn were quite variable. Cadmium varied from <1 ppm in the DFP samples to 67 ppm in one experimental M-DCP. Vanadium levels varied from 20 t o 796 ppm in one experimental M-DCP sample. Fluorine levels were in th e acceptable range, .05 to .21%. Levels of potentially toxic elements were in the tolerable range for poultry in all phosphate sources, exce pt for Cd and V in two experimental samples. Essential minerals other than Ca and P were quite variable in the 36 phosphates.