Document YGB3ZvXbYGGKXDVzGeYwG18ky

Monsanto i n d u s t r i a l c h e m i c a l s c o . I H*M N A M t * L O C A T I O N * S. Tucker - T2F November 20, 1973 Mf M M N C I PCBs T O W. B. Papageorge ' B2NA cc H . S . -- R. E . R. H . W. R . Bergen - B2SL Keller - TIB Munch - TIB Richard - T3A While attending a NAS workshop on marine pollutants held at the Marine Biological Laboratories, Woods Hole, Mass., I talked at length with Bob Risebrough (Canadian Wildlife Service/University of California) and George Harvey (Woods Hole Oceanographic Institute) regarding PCBs. The following is a summary of our conversations. Bob Risebrough reported (1) that the levels of PCBs in sewage outfalls (unspecified locations - probably California) have begun to drop significantly; (2) that they had qualitatively observed low levels of chlorinated furans in some Aroclors via GC/mass and that they were in the process of attempting to quantitate their findings. He would not even guess the level, indicating that, if they have not mistaken chlorinated methyl biphenyls (same m/e) for the furans, the levels are probably sub-ppm. I reiterated that we had not detected furans in any of our Aroclor products to date; and (3) he expressed special interest in'the possible presence of furans in used PCB heat transfer fluids. I reminded him that PCBs were no longer used as heat transfer fluids, having been re placed with non-halogen containing fluids and that the used PCB fluids were recovered and incinerated. George Harvey reported that the PCB levels found in marine samples which he obtained during their most recent cruise had decreased by a factor of 10. He was puzzled by this rapid drop and did not have an explanation for it. My own feeling is that he is being much more careful about how he collects and analyzes marine samples for PCBs and that the ships they use to collect the samples are now relatively PCB free. It will be interesting to see how he eventually rationalizes this dramatic decline in ambient PCB levels. George also gave me a pre-publication copy of a paper to be published in Atmospheric Environment (copy attached). IN . tO R C V. 1 ' 7 2 732081 2- - Generally speaking, I would say that Harvey's and Risebrough's attitude toward Monsanto and the environmental impact of PCBs have undergone a remarkable improvement. E. S. Tucker 3s NEV 022027 732082