Document oDyrOQ0RZqGJny50mZaEKqQw3

MCNS 060019 REPORT OK 4465 Inhalation Experiments C-Y^nW Animals, White rats have been employed throughout. They permit the use of a large number of animals in a relatively small inhalation installation. They thrive upon a diet very similar to man, and in the cose of these chlorinated compounds it is possible that diet may be very significant. Finally, their normal characteristics have been described so well as to make the detection of abnormalities both easy and certain. Method of Exposure. The inhalation experiments were carried out in four large air-tight wooden boxes, each capable of holding ten rat cages, size 22" x 22" x 14", in two tiers of five cages eech. VThen the experiment was not in progress the doors were opened wide and the oages kept in place (see Figure 1). At the center of one end of each box -- the inflow end -- air was introduced through a pipe 7 inches in diameter (see Figure 2). Each box was equipped with an Individual electric blower which blew the air through several feet of 7-inch pipe before entering the end of the box* An orifice was plaoed in the pipe line, and the flow of air in cubic feet per minute could be read off directly fran calibrated flow meters. A damper plaoed at the entrance of the pipe into the box was adjusted to assure a uniform distribution of the stream of air to the two tiers of cages. At the opposite end of the box -- the outflow end -- the air from each box was exhausted through a 7-inch pipe fitted with a damper and connected to a large central exhaust fan (see Figure 3). About 4 inches from the entrance of the 7-inch pipe into the box, the fumes of the substance were Introduced into the inflowing air. M0M5 060020 Fig. 1. Front view and inflow end of two boxes with rat cages in place and doors open. HONS 060021 Pig. 2. Eleotrle heater for maintaining oblorinated diphenyl at a constant temperature in place at inflow end. of hoi. HONS 060022 Fig. 3. Outflow end of two boxes showing connections to exhaust system. MONS Q60G23 *** Pjrrsx glass flasks. SONS C6G024 Specially designed pyrex glass flaalca (Figure 4), 7 3/V long and with a diameter of 1 1/2", wera uaad to bold tba heated waxes. These flasks ears made with a side arm and tuba whloh extended to the bottcm. The top of the flank was ground, and into thia fitted a short tuba 1 1/2" in length. Thia short tube was inserted Into a large rubber stopper which fitted tightly into a hols cut out of the 7-lnch pipe on the under aide (aes Figure 2). The flask in turn was placed in an electric heater made to cover it completely below the aide arm and ground glass top. Rubber tubing connected the elds arm with a compressed air reservoir and a gentle stream of air blown through the melted wax kept it In motion and assured uniform heating. Into eaeh flaak was inserted a long stem centigrade thermometer which was kept in place and could be read at any time above the 7-lnch pipe through which it passed (see Figure 2). Approximately SO gm. of pulverized rtrtunnsthuil inapiitiiuOum.. m MutfUetf chlorinated diphenyl were placed In the Vapbrlzlhg^ flask and melted in the electric heater. Fresh samples were used every other day. auttita new niKhBD^Mnrt.iiMttMjniiy rtauBdidjdijiL^i,jUijai!AAiiifft'aii nj nuna ..................... -wash And .mVHwA-. iWlinhasniuttdUflaaak The collected sublimate was always removed from the upper part of the flask and a clean top used eaob day. No sample was ever used for more than two runs. The flaak plus the contents was carefully weighed at the beginning of the run and at the end, and the loss In weight used to calculate the average amount In a cubic meter of air per minute as determined by a series of flow meter readings. The figures obtained were not absolute because of slight variations in the air flowing through the boxes end because of deposition of material on the thermome ters and on the inside surfaoes of the box, but they checked well with dlreot determinations through air samples. MONS 060025 Approximately one hour ms allowed for the mx In the flasks to malt aid corns to a oanstant temperature. At that time the hox doors sere tightly closed, air bubbled through the flasks, and the blowers turned on. This was the beginning of the exposure period. By means of the theostats co the fans and the dampers in the outflow pipes, the amount of air flowing through the boxes was adjusted and an atteqpt was nede to keep the four boxes as uniform as possible -- usually between 165 and 175 cubic feet per minute.. Experiments Exposure to chlorinated diphenyl ms begun an July 1, 1936 and ceased on November 18 of the same year. The average length of exposure ms 16 hours dally for 6 days a week. Each morning at about 9:00 exposure ceased, and between this time and 4:00 p.m. the rats were oleaned, fed, weighed, etc. In order to secure uniformity of exposure the cages were shifted on a regular schedule, since wax concentrations were somewhat higher at the Inflow end of the boxes. Preliminary runs showed that once properly adjusted, wax concentrations in the air remained very uniform from day to day, but to insure absolute safety readings of temperature, air-flow, etc. were made every night between 10:00 and 12:00 p.m. as mil as on starting and stopping. At different times during the course of the experiment tests for free chloride were made but ware uniformly negative and showed that under the temperatures used no decomposition occurred. Table 1 M0NS 060026 Conditions Maintained in Inhalation Experiment frcm July 1 to Nov. 18 Material Chlorinated diphenyl Temperature . Aversge concentration of air in box Totsl length of exposure C 165-175 Mg./ou.U. Range 0.57, High 1.19 Low 0.23 hours 1896 Average dally exposure hours 16 Results of Inhalation Experiments Ho abnormalities were seam at any time In the living rata. Blood and urlna examinations nra made; there ware no lossea in weight, and one would have oonaldared that tha animals ware perfectly sound. However, rats sacrificed after S weeks exposure showed slight liver damage, which advanced during tha next two months. The changes consisted In slight to moderate swelling of the liver cells, Increased granularity, and many mitotic figures. Hyaline inclusions were present and were invariably plentiful In animals receiving chlorinated diphenyl by Inhalation or by Mouth. . One Is forced to conclude from the experiments that an average concentration of 0.S7 mg. per cubic meter Inhaled 16 hours dslly produces definite slight changes In the liver and In this organ alone. These changes are resisted efficiently by the animals and cause no depreciation of health. The situation la not Unlike that seen In factories where acute yellow atrophy of the liver has occurred. In the case of such Instances the patients have been singled out In some way or other from large groups of fellow workmen who have been perfectly healthy. In considering the entire matter It seemed to us that the WBftissd chlorinated hydro-carbona,/if Inhaled In eufflclent concentration, might cauae a slight degree of damage to the liver. This damage Is resisted efficiently and causes no depreciation of health, but if the individual In question happens to suffer some ordinary disease of the liver the condition is superimposed upcrn a substratum of injury. In accordance with this hypothesis we determined that a dose of 0.75 oe. of carbon tetrachloride plus 0.75 co. of ethyl alcohol per kilogram of rat was entirely non-toxic to normal animals, "hen, however, this dose was given to animals which bad inhaled chlorlneted diphenyl as has been described In this experiment, the result was acute yellow atrophy MGNS 060027 -5- of the liver. It would aaam therefore that Inhalation of a concentration of chlorinated diphenyl In the manner I hare deacrlbed la capable of producing a condition which may be dangerous to tha Individual Inhaling It, though of itself no visible harm will be done. Animals removed from exposure to chlorinated diphenyl after two months Inhalation and given two months for recovery still showed liver changes when hilled and examined, so that It is evident tha alterations produced by this hydro-carbon ore persistant and Individuals who have been oaused trouble by It should be removed completely end for a long time. Tha Inhalation of a aanewhat higher concentration of ' chlorinated diphenyl over an B hour day Tha eiroumstanoaa attending this experiment are given In Table 2. Material Table 2 Temperature o 0 Average concentration of air In box Mg./ou.m. Haags Total length Average of exposure dally exposure Hours Hours Chlorinated diphenyl 153-174 0.93 High 3.23 Low 0.03 920 a Again 80 rate were used in this experiment. None at any time showed the allghteat evldanoe of lllnesa. Klcroacopie examinations, however, showed a degree of change vary comparable to that found In the IS hour experiments which have bean deacrlbed end the carbon tetrachloride test was uniformly fatal. Ownersi Cjymnwrv From these experiments wa are foroed to conclude that ccnoentratlcns of chlorinated diphenyl In workrooms should not be allowed to rise above 0.5 mg. per oublo meter of air. This caicantraticn is readily obtained by careful MOhS C60028 -6hoodlng. It Is In our opinion safe tor workmen who would not be exposed with the absolute steadiness obarseteristio of our experiments on rats and such a concentration limit would probably do away with the troublesome skin lesions which have been the particular cause far worry in regard to these compounds In the past. In addition to the inhalation experiments many feeding experiments this were done with/chlorinated diphenyl. The general changes in the liver were the same as those already described, ho diarrhea or gastro-intestlnal aspects seemed to be present. MQNS 060029