SUMMARY— A polarographic analytical procedure has been developed to give specific and quantitative responses based on the bromide content of food crops and other media. Improved extraction, ashing and oxidizing systems are used to improve recovery and reliability. The bromides present in plant material can be quantitatively removed with an aqueous‐alcohol solution, leaving the major portions of fats, protein and sugars undissolved. The ashing of the residue from this extract is simplified and allows larger samples to be processed. An absorption‐reaction train is used, first to oxidize the bromide to bromine and second from bromine to bromate. The bromate is measured for quantitation by polarography in a 1 M NH4OH/NH4CI solution. The polarogram is recorded using an applied voltage of −1 to −2 volts using the potential measured across the DME vs. a mercury pool. Application of this procedure has been made to 40 crops during the past three years. A mean recovery of 88.8 per cent has been calculated from fortified samples of every crop analyzed.

SUMMARY —Inorganic bromides may be present in food and raw agricultural commodities, in part as a result of soil treatments with bromine containing organic compounds, and in part as natural bromides from soil. Studies by various workers have shown that the organic bromide is not taken up by plants from the soil, but the compounds are readily degraded to liberate the inorganic bromide to the soil. Hence, any increase in bromide content of plants grown on treated soil can be considered to be due to treatment. The inorganic bromide ion is expected to be in solution in the cellular makeup of plants, and thus available to an extraction procedure. Experiments have shown this to be true. The data presented summarize three seasons of measurements of the bromide content of various crops. The effect of soil treatment is compared to the bromide levels occurring in these crops as the result of normal levels in soil. A further comparison is shown for the type of soil fumigant used. Data are given for ethylene dibromide, 1,2‐dibromo‐3‐chloropro‐pane, and trimethylene‐chlorobromide. It is apparent, in general, that leafy portions of the plants studied contain the greatest levels of bromide on the basis of weight. Edible parts of certain other crops have a significant uptake ot bromides from the soil.

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