Document omrvKVoVQaNm9Yk235gDBbkXD

FILE NAME: TILO (TIL) DATE: 1934 DOC#: TIL005 DOCUMENT DESCRIPTION: CT Health Bulletins ri* ir Liability in Cases of D am age b y Dogs Whooping Cough Since 1875 Location of Physicians in C onnecticut Is There Protection A gainst V en ereal Dis eases? (Radio) Laboratory Methods in O ccu p atio n al D is ease Control Progress in W ater Supply a n d S ew age T re at ment Monthly Conferences on P ublic H ealth Nurs ing The Worker a Factor A Health Broadcast on Each W eekday Bacillary Dysentery Stanley H. Osborn, M. D,, C. P. H,, Commissioner Issued Monthly by the State Department of Health HARTFORD LABORATORY METHODS IN O CC U PA TIO N A L DISEASE CONTROL Allan L. Colem an, B. S., A ssistan t Industrial Hygienist The laboratory is a phase o f public h ealth w o rk form ed on a founda tion of the m edical and rela ted sciences to a ssist in the confirmation of clinical evidence for estab lish m en t of a definite diagnosis and in the de termination of infection sources. The m ere perform ance of a labora tory test or the accum ulation o f laboratory d a ta , however, is of little value unless such tests or d a ta are in tellig en tly interpreted in terms of the particular problem or condition. This is tr u e both in general diag nostic laboratory and also in th e laboratox-y d evoted entirely to occu pational disease control. J u st as a n egative W id a l reaction is insuffici ent evidence upon which to assert the absence o f typh oid fever, so is the absence of a pathological am ount of lead in t h e urine or feces insuffi cient evidence upon w hich to assert that lead p oisoning does not exist. These findings, however, ta k e n in conjunction w ith all others in the case may be and often are essen tia l to a clear com prehension of the condi tion. If in the latter of th e se tw o cases a p roven history o f exposui-e was found accompanied by sym ptom s and p h y sica l signs of lead poison ing, these would constitute stron g presum ptive evidence for a positive diagnosis. The knowledge of actual occurrence of cases provides valuable data for the prevention and control o f occupational d isease. This alone, howevei*, is but one factor in such a progx*am. W h ile th e industrialist may be cognizant of the fa ct th a t m aterials used or evolved in certain pi'ocesses constitute a potential h ea lth hazard, h e is not fam iliar w ith the action of these materials upon health or th e concentrations w hich pre sent a health hazard. The prevention of occupational disease to d a y is no longer a matter of mere inspection of environm ent by a la y in sp ecto r. It is usually necessary to detei'mine by m eans o f exact p h y sica l and chemical methods w hether any particular environm ent is sa fe. A ctu a l determinations are made of the number o f d ust p articles present p er cubic foot o f air or of the concentration of other to x ic m aterials p resen t in the air bi'eathed by the worker. By com painng the con centration of these materials actually found with the m inim um am ount th a t w ill affect health, it is possible to say definitely w hether a hazard exists and to what extent. Samples collected in industrial atm ospheres w here toxic substances are used or evolved in th e process are ex a m in ed at the laboratory to determine the concentration o f th e m aterial to w h ich the workers are exposed. Since such determ inations u sually in v o lv e the sampling of lai'ge volum es of air, the sa m p les are g e n e r a lly secured by passing a measured volume of the air through a d evice containing a suitable medium for the quantitative retention o f th e m aterial in question. The amount of dust, gas or vapor contained in th e sam ples is determined by laboratory methods. A b rief description o f a num ber of the repre sentatives methods used in th e laboratory fo r th e control of occupa tional disease may be of interest. 250 The M easurement of D ust Exposure It is known that the inhalation of sm all particles of certain dusts may cause the development of pneumoconiosis, a fibrosis of the lungs due to dust. Certain types of pneumoconiosis, as silicosis, may be complicated with tuberculosis and result in complete disability or even dt-ath. Certain amounts of various types of dust can be breathed with out producing this condition. For example, continued exposure to less than 9 million particles of granite dust per cubic foot of air can be in haled without causing fibrosis. Such information on permissible concen trations of injurious materials can be applied to occupational disease control only when methods for determining their atmospheric concen trations are available. For control of dust hazards, it is now a routine laboratory procedure to determine the number of million dust particles pereubie foot of air. The first thing to be done in making this determination is to collect the dust from a given volume of air. The air to be sampled is drawn through a sampling device--known as an impinger-- at the rate of one cubic foot per minute and impinged at a high velocity on a glass plate under water contained in a collection flask. If the air were merely bub bled through the water, much of the dust would pass through and es cape; but by this impingement the dust is momentarily arrested, wetted b.vthe water, and thus retained. Samples collected in this manner are taken to the laboratory for examination. Here the dust particles in a measured portion of the sample are counted under the microscope. The technic described by the United States Public Health Service in Public Health Reports, March 1932, after a decade of actual use is followed in the laboratory of this bureau. In preparation for counting the sam ple is first passed through a 325 mesh screen which filters out the larger particles since it has been found that dust particles larger than 10 microns (l/2 5 0 0 th o f an inch) donot gain access to the lungs. The screening of asbestos dust, how ever, is omitted since fibres of this mineral much longer than 10 microns have b e e n found in the lungs. A one m illiliter portion is transferred to each of two Sedgwick-Rafter cells. The dust is allowed to settle for 20 minutes, after which time the particles are counted under the micro scope at a magnification of 100 diameters under light field illumin ation using an Abb Condenser. To assure a representative result, five microscopic fields are counted in each o f the two cells and the counts averaged, but the average is not taken as the final count until a cor responding control has been subtracted. The number of million parti cles of dust per cubic foot of air is calculated from the final count. Al though dust counts are always important in estimating the extent of the hazard presented, the mineralogical and chemical composition of the dust is also an important factor. The results of dust determinations are being used today in the con trol of the serious dust hazards presented by sand blasting operations, rockdrilling, foundry operations, stone dressing, asbestos industry, and other processes where dust is produced in the atmosphere. 251 Determination of V ap o r Concentrations in Industrial Atmospheres It has been necessary to develop in the laboratory various technics for the determination of the vapor content of the atmosphere to which workers are exposed. In the developm ent of such procedures it is de sirable that th e method itself be sim ple, that the apparatus he portable so that it can be used in the field and that the analyses can be made in a com paratively short time. T he sampling of atmospheres for their vapor content is generally accom plished by (1) using a solid material for the retention of the vapor (2 ) drawing air through an impinger containing a suitable liquid fo r the retention of the vapor, or (3) ob taining a sam ple of the vapor-containing air as such. The adsorption of organic solvent vapors on activated charcoal may be used to illustrate the retention o f vapors by a solid material. In such determinations a measured volum e of air is drawn at the rate of one liter a minute through a tube containing activated charcoal which has been previously equilibrated and weighed. The quantity of vapor pres ent in the atmosphere is then determ ined by the increase in the weight of the tube. It is exceedingly useful in atmospheres where the vapor in ques tion is the sole or major constituent of the solvent vapor group which may be present. Examples of determinations for w hich the activated charcoal m ethod is particularly adapted are those o f trichlorethylene vapors at degreasing tanks, or carbon tetrachloride vapors at dry cleaning equipment and benzol vapors at rubber cementing operations. The im pinger mentioned above for collection of dust samples is of value in collecting certain vapors. One of its advantages is that it per mits the sam pling of air at the rate of 35 liters per minute whereas the sampling rate of the fritted g la ss bubbler, an alternative sampling de vice, is usually only from 1 to 5 liters per minute. Since the impinger en ables one to sample larger volum es of air in a shorter period it is well adapted for field studies, provided laboratory tests show that the vapor in question can be completely retained by means of this device. This is used for example in determining the concentration of chromic acid mist in the vicinity of chromium plating tanks. Here a measured volume of air is drawn through a dilute solution of sodium hydroxide contained in the impinger. The sam ple is taken to the laboratory where the absorbed chromic acid is determ ined by a colorimetric method using s-diphenyl carbazide as an indicator. The concentration of chromic acid is expressed in milligrams p er ten cubic meters, which is approxi mately the volume of air b reathed by a worker in eight hours. D eterm ination of Gases Atmospheric gas concentrations are determined by (1) absorption of the gas in a liquid contained in a fritted glass bubbler (2) portable in struments operating on a physical or physico-chemical principle, or (3) by collecting a portion of the air fo r laboratory analysis. Gas A bsorption The fritted glass bubbler is used extensively for the absorption of gases. U sing this method it is often possible to complete the analy sis in the field. The determination of hydrogen sulfide concentrations 262 inindustrial atmospheres is a useful application of this method. A solu tionof iodine with starch is placed in th e bubbler. As air containing hydrogen sulfide is drawn through, the blue starch-iodine color fades andthe exact amount of hydrogen sulfide is determined by titration. Where it is desirable to analyze for extrem ely low concentrations, a method depending upon the color of an antimony sulfide sol produced bythe reaction of antimony tartrate and hydrogen sulfide has been de veloped at our laboratory. Physical and Physico-Chemical M ethod s Among the methods most readily adaptable to field determina tionsare those dependent upon physical and physico-chemical phenom ena. These include heat of combustion, thermal conductivity, and inter.rence of light. A greater advantage o f these instruments is that the resultsmay be read directly from calibrated dials. The heat of combustion method, for exam ple, has found large appli cability in the determination of carbon m onoxide in air. A portable in strument has been constructed which gives continuous readings of the carbon monoxide concentrations directly on a dial. Conclusion Successful control of most occupational diseases must be based on facts obtained by such laboratory procedu res as have b een described. Determination of the presence and extent of any hazard th a t may exist is dependent upon laboratory findings correlated with pathological data and information on occupational environment. Industry is eager toobtaininformation based on interpretation of such laboratory findings asshownby its numerous requests for this service. The cooperation of all those concerned in occupational disease prevention is essential to the solution of the problem. But only through properly interpreted labora toryfindings can complete control of occupational disease be assured. 253 Connecticut H ealth Bulletin l>" " For a Clean State a n d a H e a lth y People " ,i t Voi. 48 December, 1934 No. 12 i-! ! ') t. ! r S SPECIAL A RTICLES i :< Only N eufeld M ethod fo r T y p in g Pneum o cocci to be used Convicted of Practicing W ith o u t a License iii Tracing O bscure T yphoid C a rr ie r Conditions i e Drinking W ater Supplies a t Industrial Plants ! r Measles Since 1875 The L aboratory's P a rt in D isease O u tb reak s i ' (Radio) i i Approval of Respirators Index Volume 48, 1934, M onthly H ealth B ul i letin ! ; Stanley H. Osborn, M. D., C. P. H ., Commissioner Issued Monthly by the State Department of Health HARTFORD lat be rly Occupational Diseases ilk ly. 363 REPORT FOR THE MONTH OF NOVEMBER, 1934 he Dust -- Aibeito* Spraying -- Lacquer U lx * to s is .................................. 1 Lung Irritation .................................. 1 lat Lend -- Metallic SvitiMinc Poisoning .......................... Turpentine 1 Dermatitis ........................................... 1 es. Poison Ivy in Pernmtitte .......................................... 4 T o ta l................................................. 8 JX- ,ek 1 APPROVAL OF RESPIRATORS ol- The United States Bureau of Mines has recently undertaken the test rill ing of filter type respirators for their effectiveness in protecting the nd wearer against dust, fumes and mists. In view of the differences in the efficiency of various types of respirators, there has been a great need ive for some qualified organization to pass on those which can be shown to fie satisfactory. The Bureau of Mines in their "Schedule 21" has pre ire sented a procedure for making tests on respirators which are submitted :>ry to that bureau by the manufacturers of the respirators. Depending de- anon the purpose for which the respirator is designed, it is tested for illy efficiency in protection against "M echanically generated dusts result ere ing principally from disintegration of a solid, such as: The dust clouds produced in the various processes of mining, quarrying and tunneling ier- and the various industrial operations of grinding, crushing, and general processing of minerals; "Fumes of various metals (usually their chemical compounds, as ans oxides or carbonates) such as lead, mercury (except mercury vapor), jvi- manganese, copper, chromium, iron, cadmium, zinc, magnesium, alu dth minum, antimony and arsenic resulting from sublimation or the con go. densation of their vapor, or from the chemical reactions between their for vapor and gases; to ".Mists as produced by spray-coating with paint and vitreous enamels, The chromic acid mist as produced in chromium plating, and other mists of ave materials whose liquid vehicle does not produce harm ful gases or we vapors; lur- "Combinations of the preceding types; the "Combinations to include all of the preceding types. and "In addition to the above types, respirators will be tested for per of missibility for protection against a single substance of any o f the above effi- types of suspensions." her Not only is the filtering material tested to show that it w ill not allow '.nse injurious amounts of these materials to pass through, but, in addition, 01B- the design and construction of the respirator is considered, the resistance ilih to air flow is measured and finally man tests are conducted to show the Tff efficiency of the respirator when worn by men with different facial and \ contours. This bureau plans to keep on file a complete list of approved respir ators. Although it is as yet too early for all of the respirator manufac turers to have their products tested by the Bureau of Mines, it is sug gested at the present time that only those respirators be purchased which have been designed for submission to the Bureau of Mines for a test. 277