Document r547QmznMZkEgnJ3MJzJZJZV

Adult Dusting a Subject Respirable Talc Studies Project 0503.01 TO Mr. G. Lee New Brunswick N.J. February 15 1977 File 175 The data submitted by Mr. Russell in his February 8 1977 report on the above subject based on usage by 20 individuals have been employed for computing safety factors for the Battelle Studies as requested but the computations have been performed on a somewhat different basis from that employed in the infant studies You will recall that previously reported factors were based on weekly exposures of both the hamsters and infants Since I have no data on frequency of adult dusting on a weekly basis the safety factors in the following table were based on one dusting per week These factors however can easily be con- verted to n dustings per week by dividing by n where n = the median number of weekly dustings Hamster Group No. Weekly Hamster Exposure hrs 2 Multiples Hamster Exposure Expressed as of Adult Exposure Based on 1 Dusting per Week Using 50th Percentile - Using 95th Percentile | | 73 11 2 20 730 107 3 100 4 20 _ 3640 730 535 . 107 5 100 3640 535 The above factors were based on the data in column 6 of Appendix I labeled Respirable Mass Collected Micrograms since the total respirable mass collected corresponds numerically to the weighted average exposure expressed in mins m m These data are summarized below Maximum Minimum 11.2 0.2 95th percentile Average Std Dev 2.32 . 2.52 Median 1.65 50th percentile . 10 No. Observations 20 ' males 10 females JNJ 000088299 NM ) -2- -@ 95 percent of the underlying population may be expected to be less 11.2 with a confidence of 86 percent mins Converting the 50th percentile value of 1.65 week dusting gives 1.65= 0.0275mgweek . exposure Likewise the 95th : converts to 11.2= 0.187 week to a once- percentile Dividing the weekly hamster exposure values by these two quantities yields the corresponding safety factors shown above The tabulation below displays safety factors corresponding to a selection of weekly dusting frequencies Hamster Group No. 1 2 3 4 No. Weekly Dustings ~ Safety Factors 50th Percentile 3 5 ;7yj 9 15 10 8 243 1210 243 146 104 . 81 728 520404 520404 146 104 81 Based on 95th Percentile 3 - fs 9 4 2 1.61.6 1.6 15 12 178 107 59 36 21 15 12 520 5 1210 728 404 178 107 f Please call me if you have any further questions / jdm CC Mr. W. H. Ashton Mr. G. E. Heinze Dr. A. Kulkarni Mr. J. R. Marshall Ms. R. Merz Dr. S. Seltzer Dr. B. Semple Dr. W. T. Sherman Dr. W. Waggoner N. Sivertson JNJ 000088300