Recovery of Ethylene Dibromide Residues from Fumigated Whole Kernel and Milled Wheat Fractions

Abstract

Wheat and wheat products were fumigated with ethylene dibromide at dosages of 0.5 and 1.0 pound per 1,000 cubic feet for a 24-hour exposure period at 70°F. in a gas-tight fumatorium equipped with a recalculating system. The data presented in these experiments show that more than 95% of the added ethylene dibromide was recovered from whole and ground wheat samples after 10 days, reaction time at approximately 70°F. At a treatment dosage of 1.0 pound for a 24-hour exposure, fumigated wheat at 9% moisture content contained 5.8 p.p.m. ethylene dibromide at the end of the 10-day aeration period. The bran fraction of wheat initially sorbed the greatest amount of ethylene dibromide, followed by shorts, flour, and middlings. These milled fractions, on the 35th day after fumigation, had, on the average, 4.5 p.p.m. of ethylene dibromide. The wheat samples containing 15% moisture not only sorbed the greater initial amount of ethylene dibromide during the exposure, but retained several times more fumigant than the 9% moisture sample after 15 days of aeration. The total bromine residues that resulted from fumigation are reported as the sums of the ionized bromine (salt form) and the bromine equivalent to the ethylene dibromide in the samples at the time of analysis.