Document LJ6kwaGNBeYVv5n62kbgkVQxg

UNIVERSITY OF CINCINNATI DEPARTMENT OP PREVENTIVE MEDICINE AND INDUSTRIAL HEALTH THE RtTTIMNM LARORATORT COLLIDE OP MIDICINE--COIN AVENUE CINCINNATI ID. OHIO eAELI ADORES* EETLAR. CINCINNATI TELEPHONE: CAmoi 1414 September 7. 1956 Mr, Elmer P. Wheeler Industrial Hygienist Monsanto Chemical Co. 1700 S. Second Street St. Louis Missouri Dear Mr. Wheeler: We have generated a saturated atmosphere of Pydraul P-150 by means of the equipment in the enolosed photograph. Air from a Gast Rotary Blast and Suction pump (A) at the rate of 10 liters per minute as measured by a rotameter (B) passed through either one or two bubblers (C and D) each containing 500 ml of Pydraul F-150. (The bubblers were 9.75" high (O.D.) and 2.9" in diameter O.D., the air entered the bubbler through a fritted glass thimble, 7/8" * 3 3/k-) The air-borne Pydraul F-150 was passed through an lmplnger bottle (E) and then through a Milllpore filter (f) before entering a glass tube (G) on which was surmounted a thermometer. (The room temperature was maintained at either 72* or 80*F by means of an air-conditioning unit.) Nine liters of the sample were discharged into the room through an upright tube above H. Air at the rate of one liter per minute was drawn from a sampling port (H) and passed through a furnace (J) (maintained at 850*-900*0 and equipped with a platinum strip). The furnace was humidified by means of a wet wick at I. The thermally decomposed Aroclor was collected in two midget bubblers (K) in series. (The bubblers each contained 10 ml of 0.1 N NaOH and were equipped with fritted glass thimbles.) A drying tower (L) preceded a capillary flowmeter (M) and the sampling pump (N). The thermally decomposed chloride was determined turbldli^jplcally as given in my memo of July 7, 1956, except we^aEle to eliminate the step for the removal of phosphate, since the phosphate did not Interefere because it was soluble in nitric acid. MOMS 090853 Page 2 Mr. Elmer P. Wheeler September 7 1956 The results obtained were as follows in one study (No. 1) which included 24 smaples (J4.8 analyses) each of whloh was collected for 15 minutes. Number of Bubblers for Generation of Vapor Temperature I'F) Average of six samples; micronrams of Aroclor 1242/ liter 1 72 4.8 2 72 6.1 1 80 5.2 2 80 6.5 These samples are undoubtedly high, since it was found after their analyses that a small crack was present in the Millipore filter. The results of a second study on a similar number of samples (15 minutes for collection) were as follows: Number of Bublers for Generation of - Vapor Temperature CP) Average of six samples; micrograms of Aroclor 1242/ liter 1 72 3-5 2 72 1.9 1 80 2.5 2 60 2.7 Ave. of l Ave, ) A few samples In a third experiment were collected for a period of one hour, these results were as follows: Number of Bubblers for Generation of_Vapor____ 1 2 1 2 Temoerature ____i:p>_____ Number of Sample 3 Average Micrograms of Aroclor 1242/ liter 72 2 0.95 72 2 2.25 80 1 1.1 60 1 __ Ave. of Ave 1.55 HONS 090854 Page 3 Mr. Elmer P. Wheeler September 7, 1956 At 745 mm and 25 "C one ml crogram of Aroolor 1242 vapor Is equivalent to 0.0969 ppm by volume (1 mg/l = 96.9 ppm). Therefore 2.65 yA " 0.256 ppm and 1.55 yA = 0.150 ppm. Although there are fewer samples in this latter determination, I am inclined to believe it is probably the best value. Because of the number of samples and the deviation in them it is doubted that the difference between 1 and 2 bubblers on the one hand and between 72" and 80"F on the other hand can be statistically differentiated without many more samples. We shall proceed with the determination of the threshold odor concentration and effectiveness for removal of Pydraul F-150 by passage through MEA very shortly. Sincerely yours l seph P. Treon JPT: fk cc: Mr. Elmer Wheeler (Washington, D.C.) MONS 090855