Document dazKJLd5BaB0nKwEgNE2ONVyQ

, Monsanto Company 8 0 0 N. Lindbergh Boulevard St. Louis, M issouri 63167 Phone: (314) 6 9 4 - 1 0 0 0 May 23, 1983 DEPARTMENT OF MEDICINE 8 ENVIRONMENTAL HEALTH Dr. Robert A. Neal President, CIIT P. 0. Box 12137 Research Triangle Park, N.C. 27709 Dear Bob: As you well know, the problem of a tolerable level of TCDD in soil is ultimately to be based on the bioavailability of the dioxin. I asked George Levinskas to write down an outline of a bioavailability study. His protocol outline is attached. We learned last week that there was a site at Quail Run where the concentration was alleged to be 1,000 parts per billion. I am going to attempt to get a sample of this soil and if in fact the concentra tion is over 1,000 ppb, I then would like to do the bioavailability study. I shall be attempting to obtain a soil sample. If the soil contains less than 1,000 ppb, I-doubt whether a negative study in guinea pigs would have meaning. I will be getting in contact with you again after I have obtained a soil sample worthy of such a study. Obviously, if I am that success ful, I will need to have you tell me whether you think you could do the study or should do the study, or whether Monsanto should attempt to do it. In addition, I do want your thoughts regarding modification of Levinskas' protocol. Thank you for your continuing help. Sincerely, \ Eric 1. .- y ^ >t w o George Roush, Jr Director s" Z>v u & oO C04175 Rationale : General Outline: Test Systems: TCDD experiments Demonstrate that dioxin bound to soil is not as hazardous as an equivalent amount of free dioxin, i . e . , its bioavailability is reduced. Since dioxin which has "a g e d " on soil may be more tightly bound than dioxin recently mixed with soil, contaminated soil with the highest possible level of dioxin will be used. The dioxin content of the soil will be determined. Animals will be dosed with soil containing dioxin. Other animals will be dosed with an equivalent amount of dioxin, preferably extracted from the soil itself. The biological effects of the soil/dioxin and dioxin groups will be compared. Some animals may need to be dosed with soil without dioxin to assess the effects of soil alone. It may be possible to monitor e x cre ta or tissues to show n on -absorp tion , minimal ab so rp tio n , or d eg re e of absorption of dioxin. Guinea pigs - oral dose soil, soil plus dioxin, dioxin End point is death or survival. Feces, urine analyzed for dioxin? Guinea pigs - dermal dose soil, soil plus dioxin, dioxin End point is death or survival. Skin assay for dioxin? Rabbits - ear dose for chloracne soil, soil plus dioxin, dioxin T his test could p rovid e some sem iquantitative data as to the amount of dioxin required to produce chloracne. ;GJL 5 20/83