REPORT FOR ANALYSTS
This Month's REPORT FOR
ANALYSTS
. . . is α condensation of several p a p e r s presented a t the Symposium on Methods for Analysis of Pesticide Residues. They w e r e presented jointly b y the Divisions of Analytical Chemistry a n d Agricultural a n d Food Chemistry, a t the spring meeting of the AMERICAN CHEMICAL SOCIETY at
Miami.
The papers included in the condensation are: L· "Development and Status of Modern Analytical Methods for Pesticide Residues in Crops and in Foods," by F. A. Gunther, Uni versity of California Citrus Experiment Station, Riverside, Calif. Courtesy Esso Research & Engineering Co.
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"Residue Determinations—A Limiting Factor in Pesticide Usage," by Joseph A. Noone, National Agricultural Chemicals Association, Washington, D. C.
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"Some Basic Principles Involved in Obtaining Valid, Useful Pesti cide Residue Data," by C. H. Van Middelem, Department of Food Technology and Nutrition, Florida Agricultural Experiment Station, University of Florida, Gainesville, Fla.
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"Important Considerations in Collecting and Preparing Samples for Residue Analysis, " by Louis Lykken, L. E. Mitchell, and S. M. Woogerd, Shell Chemical Corp., New York Citv, Ν. Υ.
op
A multi-purpose unit with quickly adjusted vertical opening, by hand wheel, per mits many different set-ups in minimum time.
22
"Analytical Method and Residue Data Requirements for Federal Registration of Pesticide Formulations," by Thomas H. Harris, Pesticide Regulation Section, Plant Pest Control Branch, Agricul tural Research Service, U. S. Department of Agriculture, Washingtion, D. C.
Hydraulic
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ANALYTICAL CHEMISTRY
on the quantity resulting from sufficient pesticide needed to protect the crop. It is necessary, therefore, to provide data showing residue levels resulting from recommended or proposed use of a given pesticide on a given crop. The burden of obtaining required informa tion is placed on the manufacturer. Unless such data are forthcoming, there is no basis upon which to register the material. Without this registration, the company cannot ship the pesticide in interstate commerce. Prerequisites for establishment of tolerance standards are knowledge of the toxicity of the residue and of the amount of residue resulting from recom mended use of the pesticide. A few years ago acceptance or rejection was based only on the first requirement. As a result, well standardized programs of toxicity determination have been developed. Difficulties now experi enced in obtaining registration are not those relating to toxicity. They accrue from the necessity of obtaining quanti tative residue data, not only for any new products that may be under develop ment, but also for those chemicals
whose usage has been long established. Although much of this work has been done, many old line pesticides do not yet have necessary clearance. With out the residue data required by law, these cannot be maintained on the ac ceptable list. Government Requirements are Extensive
The question then arises as to the amount of data that are needed. In general, industry spokesmen feel that it is necessary to make separate deter minations of residues for each com pound being considered, for each crop, and for each method of application. Further, each of these tests must be replicated four or five times to adjust for regional differences in climate, soils, and horticultural practices. The De partment of Agriculture indicates that data should, in general, include ten results each on treated samples, un treated samples, and on untreated samples to which known quantities of the pesticide have been added. In par ticular cases this requirement may be
