Document 2kj2e0VV6nbJ0BLY6nvxdY3R

Monsanto MONSANTO INDUSTRIAL CHEMICALS CO. BOO N. LimJbtrgh Boulivird St. Leu>*, Missouri 63186 Phono: (314) 6S4-I000 May 20, 1976 / Dr. Theodore . Mel ggs USEPA r National Field Investigation Center Bldg. 53 Box 25227 Denver Federal Center Denver, Colorado 80225 . . Dear Dr. Melggs: During Tom Gallagher's recent visit to Monsanto's Research Center in St. Louis, we mentioned some anomalies we encountered when using perchlorinatlon techniques to measure PCB's. Tom suggested that we alert you to our concerns. I have attached a copy of a letter we sent to Dr. Wallen In March which describes our findings. We recommend that the perchlorination technique hot be used without a confirming method for measuring PCB's. Hope to see you in Chicago In June at the ASTM meeting. Sincerely, ss Attachment bcc: R. E. Keller J. C. Weber $ P. Mleure, Ph.D. DSW 012508 * unit of Mon,into Compmy STLCOPCB4002433 March 15, 1976 Dr. I. Z. V7allen Environmental Protection Agency Office of Toxic Substances 401 M Street S.W. Washington, DC 20460 Dear Dr. Wallen: Monsanto has a concern over the validity of the perchlorination technique used by EPA and others to measure ar.c/or confirm polychlorinated biphenyls in environmental materials. In our investigation of the perchlorination method, we have found that such chemicals as biphenyl, alkylated biphenyl, and many other substituted biphenyls, interfere with the perchlorination technique. It also appears that various petroleum components may interfere. If these chemicals were present in environmental materials that were^being tested for PCB's using the perchlorination method, erroneously high PCB concentrations would be reported. A recent-article in the Journal of the AOAC (Vol.58, No.3, 1975) points out two other limitations of the perchlorination procedure: 1. High and variable reagent blanks, which cause erroneously high findings. 2. Formation of bromononachlorobiphenyl, which causes- low recoveries. A copy of the article is attached. ` DSW 012509 STLCOPCB4002434 Dr. I. E. Wallen -2- i-iarch 15, 197 6 Since these limitations can lead to significant errors in determining trace levels of PCB's in environmental samples, we suggest that EPA carefully review the validity of the perchlorinaticn technique. Results that have been obtained using this technique may not be valid. If any other information is needed, please let us know. Sincerely, J. Coleman Weber Manager, Product Acceptability man cc: Dr. A. C. Trakowski Environmental Protection Agency bcc: W. C. Hammann - T3A R. E. Keller - TIB J. P. Mieure - T2F D. Wood - B2SC K. W. Easley - Washington 1920 R. G. Kaley - T2F OSH 012510 STLCOPCB4002435