Document mpGjqBDB5YXkD98wGMvemY16b

2/2/87 Mike, Thanks for the copy of the opus on "dioxin" exposure. I have been ingetsting it (no, not "dioxin"!) a bit at a time. X have not completed my review, nor have I collected my thoughts on the matter. However, I did want to share my initial reactions with you as ypu requested by "early February". 1. This is quite an impressive effort that you guys -- as I understand it -- had to do in addition to everything else you had going! I remember our first little chat (with Chuck Nauman), and I envisioned a 20-30 page summary. You guys have really given this material a much closer look-see. I found it to be be interesting. 2. The folks in Region 5 have been raising a number of "dioxin"-related exposure questions. I believe this effort would be of great interest/help to them. I understand that they (Larry Fink and Milt Clark) will get a chance to review the work. For example, Milt has raised questions -- and generated scenarios -- regarding the ingestion of 2,3,7,8-TCDD associated with home-grown veggies grown in the the environs of contaminated soil. You might want to consider this as well. 3. It seems to me that there are some major areas upon which we need to reach consensus -- in the face of the current data, or lack thereof. These areas include: a. Volatilization b. Photodegradation, with the possibility of increased levels of lower' chlorinated CDDs/CDFs. c. Bioavailability, from an operational point of view d. Utility of pharmacokinetics at this point in time (to quote a perhaps unfortunate phrase). I have concerns/questions about where the document ends up on each of these issues. I will try to focus these concerns by the end of the week. Thanks again, Don Barnes cc. Ad Hoc Committee on the Liberation of a Risk Characterization for 2,3,7,8-TCDD