REJECTION OF THE PROPOSED TOLERANCE IS REQUESTED

The establishment of zero tolerances for DDT on cottonseed and other raw agricultural commodities would have two very deleterious effects on U.S. agriculture. It would, in effect, ban further use of DDT for important agricultural purposes. Furthermore, it would create chaos in agriculture because traces of DDT can be found in all agricultural commodities and would continue to be found for years to come because traces are widespread in the environment. An exception to exclude residues resulting from applications made prior to an order establishing zero tolerances would be untenable. First of all, there would be no way to distinguish in a commodity between residues from applications before and after the order. Secondly, DDT is used extensively in countries such as Mexico and traces from current use in such countries would continue to drift into the U.S. and find its way into our agricultural commodities. The situation in bordering states like Texas, Arizona, and California would be extremely critical in this respect.

In view of the above consideration, the overall safety of DDT to man and his environment, and the overwhelming importance of its continued use for many agricultural and public health purposes, the Food and Drug Administration of the U.S. Department of Health, Education, and Welfare is urged to strongly reject this and any other petition aimed at establishing zero tolerances for DDT on raw agricultural commodities.

SECTION II.-STATEMENT OF THE NATIONAL COTTON COUNCIL OF AMERICA ON THE ESSENTIALITY AND SAFETY OF DDT USED AS A COTTON INSECTICIDE-JANUARY 29,

1971

(Federal Register Notice, January 20, 1971, DDT/2, 4, 5–T)

DDT RESIDUE INVESTIGATIONS, 1969-701

(James M. Brown) 2

BACKGROUND

Field tests on cotton were established in 1969 at Florence, S.C.; Stoneville, Mississippi; Waco, Texas and Shafter, California. A University of California entomologist was responsible for conducting the test at Shafter and USDA entomologists were responsible for tests at the other three locations.

Treatments involving four rates of DDT, including a zero rate as a check, were tested. At each test location, the recommended DDT rate for a severe cotton insect infestation for that particular region was one treatment. Another treatment consisted of twice the recommended rate and a third treatment was one-half the recommended rate. At the Florence, S.C. test site, a high number of applica tions, 25, was purposely used. Specific rates, numbers of application and dates are indicated in the tables of results. Treatments were replicated three times at each location.

Fifty-pound lots of machine-delinted cottonseed produced from the plots were divided into 25-pound sublots. The Oilseed Products Research Center, Texas A & M University, College Station, Texas processed the sublots of seed in its pilot program in accordance with recognized and acceptable processing procedures. In commercial practice some cottonseed are processed by solvent extraction and some by screwpress extraction. For this reason one-half of the sublots were extracted by each process.

From this processing, samples of cottonseed, hulls, meal (screwpress and solvent extracted), crude oil (screwpress and solvent extracted) and refined oil (screwpress and solvent extracted) were collected. DDT, DDD and DDE analyses of these samples were made by the Alabama Pesticide Laboratory in cooperation with Auburn University, Auburn, Alabama.

The results of these tests are presented in the following tables. The levels of DDT and its metabolites, DDD and DDE, in or on cottonseed were below

1 These investigations were sponsored by Cotton Incorporated (formerly Cotton Producers Institute, Memphis, Tennessee), Raleigh, N.C. with the National Cotton Council of America, Memphis, Tennessee cooperating.

2 Manager of Production Technology, National Cotton Council of America, Memphis, Tennessee. Formerly Manager of Pesticide Residue Research, Cotton Producers Institute.

RESULTS

the accepted tolerance level at all rates of application. Residue levels in or on cottonseed hulls were somewhat higher than for the whole seed. This is expected and explained on the basis of a "concentration effect". Most of the DDT residue would be expected to be on the outer parts of the seeds which are the seedcoats or hulls. When the hulls are separated from the internal seed contents, the level of DT on a per unit weight basis naturally is higher than for intact seed. The amount of DDT and its metabolites found in both screwpress and solvent extracted cottonseed meal was low. The highest level found was about 0.3 ppm and then only two out of 32 samples were this high. Most of the samples showed levels less than 0.1 ppm. The residue levels in the crude oil for both extraction processes were not very different from those in the meal.

The most significant aspect of these investigations deals with the refined cottonseed oil which is used in many products for human consumption. No detectable traces of DDT, DD or DDE were found in any of the refined oil samples for either screwpress or solvent extraction processing. This substantiates the results reported by Smith et al (1968). They found that chlorinated pesticides were removed from crude vegetable oils by processing procedures. In fact, either the hydrogenation or deodorization steps effectively removed any residues that were present.

It is quite obvious from the resuts reported here and from other studies that residues of DDT and its metabolites do not present an imminent hazard to the public.

LITERATURE CITED

Smith, Keith J., Polen, Percy B., DeVries, D. M., and Coon, Francis B. Removal of Chlorinated Pesticides from Crude Vegetable Oils by Simulated Processing Procedures. Jour. Amer. Oil Chemists' Soc. 45 (12): 866-869. 1968.

ACKNOWLEDGEMENTS

The assistance of the following scientists who cooperated in different phases of these investigations is gratefully acknowledged: Mr. C. P. Parencia, Entomologist, USDA, Beltsville, Maryland; Mr. Al Hopkins, Entomologist, USDA, Florence, S.C.; Dr. Ted Pfrimmer, Entomologist, USDA, Stoneville, Mississippi; Mr. C. B. Cowan, Entomologist, SDA, Waco, Texas; Dr. Tom Leigh, Entomologist, University of California, Shafter; Dr. Carl M. Cater, Head, Oilseed Products Research Center, Texas A&M University, College Station, Texas; Dr. F. S. Arant, Head, Department of Zoology-Entomology, Auburn University, Auburn, Alabama; and Mr. Rex Richburg, Director, Alabama Pesticide Laboratory, Auburn Alabama.

1 Composite 50-pound lots of cottonseed harvested for each replication made up of approximately equal amounts from plots sprayed with X, X, and 2X rates of DDT. Checks consist of composite 50-pound lots from 3 untreated plots. 2 Refers to trace levels less than 0.01 p.p.m.

Bleached, hydrogenated, and deodorized.

SELECTED RESEARCH PROJECTS SUPPORTED BY COTTON PRODUCERS

(Cotton Incorporated Research Program)

Cotton farmers, like other segments of our society, are concerned about environmental pollution from all sources including pesticide usage, industrial and human waste, radioactive fallout, exhaust pollutants from internal combustion engines and others. In fact, through their own self-financed program, they support numerous research projects that offer a great deal of potential for reducing the chances of environmental pollution caused by agricultural chemicals. In most cases the results from these investigations will be applicable to other crops. Brief statements on the various projects and some of the possibilities follow:

1. Studies on systemic insecticides at the University of California (Riverside) are aimed at development of chemicals that control specific cotton insects without killing beneficial insects. This approach eliminates the problem of drift of insecticides to non-target areas. (1969-1970-1971–

.)

2. Also at the University of California (Riverside), studies on integrated chemical-biological control of cotton insects are underway. The goals are to use as little insecticide as possible and to utilize to the utmost the advantages of alternate host or trap crops and natural predators. (1969-19701971- .)

3. In cooperation with USDA at Texas A&M University, studies are underway to develop slow-release formulations of systemic insecticides that would reduce the amount of insecticides needed for an adequate level of control. Preliminary information indicates that 1 lb. of slow-release systemic insecticide applied in the furrow at planting provides as good boll weevil control as 2 lbs. of non-slow-release material applied as a side-dressing at the square stage of plant development. (1969-1970-completed)

4. Studies at the Southern Research Institute in Birmingham are aimed at developing chemosterilants for the sterile-male technique for controlling boll weevils. This would reduce the need for field applications of insecticides for control of this major cotton pest. (1969-1970-completed)

5. At the University of Arkansas, research is underway to determine the cotton plant hormones that affect the boll weevil's ability to diapause. Without this ability to diapause, the weevil cannot survive during the winter. 19691970-completed)