Document V3Jreoa37GNmpzJ1mOX7KaEEK

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY SURVEILLANCE AND ANALYSIS DIVISION REGION VII 25 FU N STO N R O AD KANSAS CITY. KANSAS 1 1 5 A pril 25, 1979 Dr. H. Denny Donnell, Director 'Section fo r Disease Control Missouri D ivision o f Health P.0. Box 570 Jefferson C ity, Missouri 65101 Dear Dr. Donnell: During our phone conversation on April 23, 1979, I agreed to advise you o f the status of our attempts to confirm the presence o f dioxin in the material- s p ille d in Sturgeon, Missouri and to determine which dioxin isomer was present in the*material. We are now sure that dioxin ( s p e c ific a lly a tetrachloro-dibenzo-p-dioxin or TCDD) was- present in the s p ille d material at a concentration of approximately 20 parts per b illio n . The second part of your question is more d if f i c u l t to a-n-swer. There are 22 th eoretically possible TCDD isomers. Presently we believe the TCDD present in the sp ille d product includes one or more o f the follow ing five isomers: 2.3.7.8- TCDD 1.2.3.8- TCDD 1.4.6.9- TCDD 1,2,3,4-TCDD 1.2.6.9- TCDD This conclusion is based on the retention time we have observed fo r the TCDD in the s p ille d product relative to retention times of other isomers published in the lite ra tu re . Since we have not yet been able to d if f e r entiate between the fiv e compounds lis te d , we are therefore treating the material as i f i t were the highly toxic 2,3,7,8-TCDD isomer. I' am sOre from our conversation that I have not answered a ll of your questions. I am equally sure that you realize we are working on the fro n tie r o f science and f u lly appreciate the analytical problemsinvolved in providing the answer you seek. Sincerely yours, B illy J. Fairless Chief, Laboratory Branch Surveillance and Analysis D ivision Region VII cc: Carl Blomgren Harry Gilmer <0^ fV- - > ?* # * *