Analytical Chemistry — Key to Better Health - ACS Publications

member of the School of Public Health, consultant to the Institute of Industrial ... other technical societies in the field of industrial hygiene and ...
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REPORT

FOR

ANALYSTS

Analytical Chemistry — Key to Better Health Just as the footings of a fine building are buried out of sight in the e a r t h , hidden from view, so is the w o r k of the analysts who lay new footings for new scientific structures. How analysts keep building sound foundations for an e x p a n d i n g industrial structure is well exemplified by the w o r k of analysts in the field of public health and industrial hygiene. This article, the second in our new feature, Report for Analysts, is based on the Anachem A w a r d address of the author before the Association of Analytical Chemists at Detroit in June.

William G. Fredrick, a native of Lockland, Ohio, has been director of the Bureau of Industrial Hygiene of the Detroit Department of Health since 1946. He had been chief industrial hygiene chemist with the bureau since its creation in 1936. He is a faculty member of the School of Public Health, consultant to the Institute of Industrial Health at the University of Michigan, and instructor at W a y n e University College of Medicine. Dr. Fredrick was graduated from the University of Michigan with a B.S. in 1 9 3 0 , an M.S. in 1 9 3 2 , and a doctorate in 1 9 3 6 , hav­ ing majored in analytical chemistry. At the present he is engaged in inves­ tigating effects of air pollution on public health in Detroit. He is active in the Detroit Section of the AMERICAN CHEMICAL SOCIETY and a host of other technical societies in the field of industrial hygiene and analysis. VOLUME

2 8, N O . 9, S E P T E M B E R

ι \ N A L Y T I G A L chemistry is a science of identification and measurement of matter, usually inanimate in character. W i t h o u t it, little progress in the realm of physical and biological science can be made. Analytical chemistry is in fact the foundation upon which our entire scientific structure is built, and without such a dependable footing, there could be no real structure. U n ­ fortunately, j u s t as t h e footings of a fine building are buried out of sight deep in the earth, hidden from view, so is t h e work of the analysts who lay new footings for new scientific struc­ tures. I would like to clear away the obscuring earth and superstructure from the footings of just one such struc­ t u r e — t h a t which represents m a n ' s struggle for good health in an unfriendly, even hostile, physical and chemical environment—so t h a t all m a y see the essential contribution of t h e analyst a n d of the analytical chemistry which he represents. For centuries, m a n k i n d has defined health in t e r m s of freedom from disease, a n d has usually t h o u g h t of disease in terms of the result of infection of his body with unfriendly microorganisms. Until very recent times, there ivas nothing substantially wrong with such a concept, because most of the ills a n d infirmities of m a n and his failure to live o u t a life span of theoretically reason­ able length were due to plagues a n d epidemics caused by microorganisms. Shortly after the germ theory of dis­ ease was established as fact, about a century ago, there developed the science of public health and preventive medicine to combat the communicable diseases. 1956

Success developed along several fronts, first most notably in environmental sanitation and t h e development of vaccines, then in improved nutrition and shelter, and lastly in the develop­ m e n t of antibiotics—success so great in fact t h a t not only has m a n ' s life expectancy been more t h a n doubled b u t also infant and m a t e r n a l mortality has been dramatically reduced. I t would seem t h a t the millennium, as far as m a n ' s health is concerned, should be a t hand. B u t as long ago as 1920 it began to appear to a few ob­ servant public health workers t h a t all was not going well. As m a n began t o live longer because he did not die from infectious diseases, he began to de­ velop a whole new complex of h e a l t h difficulties which could not be ascribed to microorganisms, some which p r e ­ maturely shortened his life, but m a n y more which reduced his capacity t o enjoy living or to be a productive member of our society. Diseases of t h e heart and arteries, diseases of the mind or nervous system, cancer, allergy, or chronic organic degenerations began to appear in ever-increasing number. A p ­ parently stresses were appearing in m a n ' s environment other t h a n micro­ organisms, which sometimes produced p r e m a t u r e d e a t h a n d sometimes re­ duced well-being a n d productive use­ fulness. I t became urgently necessary t o revise our thinking concerning health and disease, and, today, health is de­ fined in the positive terminology of a sense of physical, social, and m e n t a l well-being, a n d disease or ill health is generally recognized as the result of the combination of all adverse environ7 A

REPORT FOR ANALYSTS

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mental stresses, chemical or physical as well as that due to microorganisms. It would further appear that chemical and physical energy stresses are of dom­ inant significance. It had been known for centuries that certain chemical stres­ ses were associated with health im­ pairments and specific disease condi­ tions. Sickness and death resulting from the gases from fire certainly were recognized when the first primitive man brought his cooking fire into the cave. Lung diseases peculiar to miners were described at least five centuries ago. In fact, cobalt takes its name from the evil earth spirit believed re­ sponsible for the extremely high mor­ tality due to lung disease of miners who extracted the ore in which the element was first discovered. It now appears that cobalt itself was in part responsible for this lung disease, although probably to a rather minor extent. That artisans who worked with mercury and lead developed palsy, loss of memory, and insanity were known to the alchemists. The discovery that potters and ceramic workers frequently developed "a rot of the lungs" was known in antiquity. In general, the association of disease with certain occupations was recognized, but the causative agent was unknown. In any event, the problem was unim­

portant in the face of the overwhelming epidemics of infectious disease, or if the work was too deadly, it was done by captive slave labor, debtors, and criminals whose life was considered of little or no value by the society of that time. I n d u s t r i a l R e v o l u t i o n Brings H o s t of P r o b l e m s

It is perhaps an irony of fate that at about the same time that the discovery that germs caused disease made possible the organized public health attack upon them, there began the industrial revo­ lution which was destined to put everincreasing numbers of workers into enclosed work spaces and develop great concentrations of urban populations. Further, there began the era of modern synthetic chemistry, which was destined to introduce into man's environment thousands upon thousands of new chemicals in ever-increasing amounts. From the very nature of things, these increasing amounts of chemical sub­ stances were destined to appear first in the work places of the industrial world, as nations changed from agrarian to industrial civilizations. It is not surprising that man's health re­ sponded adversely to this new or magniANALYTICAL

8A s

CHEMISTRY

REPORT FOR ANALYSTS fied onslaught of chemical stress. B y the end of World W a r I it was a p p a r e n t to everyone closely associated with t h e work place t h a t in spite of t h e best efforts of all concerned, t h e situation was becoming critical. A n d these ef­ forts were not exactly p u n y . Early in the industrial revolution, t h e development of first steam a n d t h e n electrical power m a d e possible t h e in­ troduction of the machine, which m a d e mass production possible. Along with this increased mechanization came t r a u ­ matic injury t o workers, amputations, lacerations, eye injuries. First came the industrial surgeon or physician t o t r e a t t h e injured a n d then t h e safety engineer t o prevent accidents by guard­ ing machinery, devising safe work methods, providing personal protective equipment. W h e n sickness began t o result from chemical stresses in the work environment, this t e a m was already a t hand t o take on this new problem. O u t of their efforts arose a reasonably good understanding of t h e chemicals, dusts, gases, vapors, a n d mists which were likely t o cause occupational dis­ ease, a n d a n excellent understanding of the medical and physiological n a t u r e of t h e more acute forms of these diseases. N o t so successful were their efforts in recognizing the cause and effect relation­ ship between work exposures a n d t h e

more chronic or slow-developing health impairments which we now know makes u p t h e bulk of such diseases. A t t e m p t s either t o prevent or cure the occupational diseases m e t with very limited success. F o r this reason, b y the end of World War I, t h e situa­ tion h a d become so acute t h a t some new health approach h a d t o be made if mass production m e t h o d s and indus­ trialization were t o continue t o expand. This new approach was discovered and its methodology is n o w known as in­ dustrial hygiene. I t provides for (1) the recognition of the work environment stresses which are capable of producing health injury, (2) the evaluation of t h e stress in q u a n t i t a t i v e terms, a n d (3) the control or reduction of these stresses to tolerable levels when necessary. Now there w a s really nothing new in the first a n d last steps of procedure— they had been known for a long time— b u t i t was impossible t o execute t h e control or reduction procedure without knowledge of t h e magnitude of t h e stress which m i g h t be cither safe or harmful. I t was t h e introduction of step two, evaluation or measurement, which for t h e first time i n t h e history of m a n ' s industry m a d e i t possible t o prevent work-derived illness a n d t o learn more a b o u t its prevalence a n d nature.

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2 8, N O . 9, S E P T E M B E R 1 9 5 6

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REPORT FOR ANALYSTS Analysts and Analytical Chemistry Enter the Scene

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It is at this point that analytical chemistry and the analyst entered into the picture. The first attacks were directed against three old veteran occupational diseases: silicosis, a lung disease caused by the inhalation of silicon dioxide dust; lead poisoning caused by the inhalation of the dust of lead or its compounds; and mercury poisoning caused by the inhalation of mercury. These three diseases «ere known to the ancients and have plagued workers throughout man's recorded history without remission. Silicosis was seriously crippling entire industries, especially granite cutting for tomb­ stones and building blocks, coal and metal mining, the iron and steel foundries, and pottery and ceramics. As recently as 1934-35, the greatest epidemic of lead poisoning ever re­ corded occurred in Detroit in our auto­ mobile body industry. Let us take a look at two of these typical analytical problems.

Silicosis—An Age-Old Problem The beginnings of this story involve traditional methods of analysis—not easy but conventional, which established the fact that what we now call silicosis is caused by the dust of silicon dioxide exclusively, regardless of its crystal structure or mineralogical type. The first attempts to collect dust from the air met w ith substantial failure be­ cause the median particle size of most such dusts was about 1 micron, with few particles above 2 microns in size. It passed through all filter media then available, through which air would pass in any practical volume. The first successful method was a high velocity impingement in water device known as a Greenberg-Smith impinger. Methods using high velocity impingement on adhesive glass surfaces and thermal precipitation also were developed. The latter had the short­ coming of very small sample collec­ tion capacity. As no chemical method was then available to determine the small weight of silica collected, analysis was accomplished by counting the particles, and expressing dust concen­ trations in terms of millions of particles per cubic foot of air. Experience has since determined that if the silica dust concentration is kept below 5,000,000 particles per cubic foot—which to the eye looks like clean air—the likelihood of silicosis developing in the working lifetime of exposure is substantially reduced. Some improvements in the counting technique ANALYTICAL

CHEMISTRY

REPORT FOR ANALYSTS

still need to be made to improve particle resolution in the 0.5- to 1.0-mieron range. Particles below 0.5 micron in size have little physiological significance in sili-

Lead Poisoning— Long a Crippling Disease

Until as recently as 1930, it was gen­ erally considered that occupational lead poisoning resulted from eating lead and its compounds. Lead poison­ ing, like silicosis, is a disease which frequently completely and permanently disables its victims without seriously shortening the life span. That the ingestion theory for the entrance of lead into the body stood for so many centuries is not surprising because the few attempts to demonstrate the pres­ ence of lead dust in the air failed. The work on silica indicated the need for air sampling methods capable of catch­ ing fine particles. The problem was not solved, how­ ever, until Fischer and Leopoldi in the early 1930's developed the dithiozone method for determining trace quantities of lead. It then rapidly developed that workers could not safely breathe air containing more than 0.15 mg. of lead per cubic meter. Even if one were quantitatively to remove the lead from a cubic meter of air by the labor­ ious methods then available, the quan­ tity of lead available for analysis would be below the limit of sensitivity for pre-dithiozone-era methods. It soon became apparent that then existing collection methods failed for lead fume with particle sizes ranging below 0.3 micron and an analytical-type electrostatic precipitator was developed for air sampling. With a sensitive and reliable method for measuringlead concentrations in trace quantities (small amounts in high dilution), it soon was discovered that the rate of worker lead intake could bo established by either measuring the lead concentra­ tion of the blood or the lead excretion rate in the urine. Maximum permis­ sible levels for blood and urine are about 0.08 and 0.015 mg. per 100 ml. Today it is completely feasible, in fact an actuality, to operate all types of so-called high hazard lead-using operations without a single case of lead poisoning. Without such environ­ mental analytical control, the manu­ facture of the modern design of auto­ mobile body would be an impossibility. It is estimated that in the production year of 1934-35, over 50,000 cases of excessive lead absorption occurred in body manufacture workers. In the year 1955-56, not a single case came to the attention of the Detroit Health Department. VOLUME

2 8, N O .

9, S E P T E M B E R

Analysts Develop N e w Concepts and Techniques

These examples serve to show how age-old problems have been met and at long last solved. They also show the problems which the analyst has had to solve. Most occupational dis­ ease from chemicals is due to the inhala­ tion of the chemical in the gaseous or aerosol form at high dilutions in air. Rarely indeed may breathable air be contaminated with more than 500 p.p.m. by volume of a gas or vapor or 15 mg. per cubic meter of a solid or liquid. More usual permissible concentrations approximate one tenth of this amount. Some lie below 1 p.p.m. or 1 y per cubic meter. Entirely new concepts and principles have had to be applied or developed to permit quantitative collection of ade­ quate amounts of material in a practical time interval. Most troublesome has been development of methods for col­ lecting aerosols below 0.3 micron in size in a form which can be handled analytically. Only recently has suc­ cess been finally achieved by the de­ velopment of membrane filters and glass fiber papers, both of which are highefficiency, self-energizing electrostatic filters. An entirely new system of analytical chemistry which we now recognize as trace analysis has had to be developed. The determination of a few micrograms of material in 100 ml. of solvent is now routine for hundreds of substances, and the list is ever increasing. It would appear that a triumph of this magnitude would be sufficient, but practical considerations soon dictated the urgent need for portable directreading instruments which would meas­ ure the environmental chemical stress immediately as the worker carried on his normal work activities. Such equip­ ment must meet the sensitivity require­ ments previously mentioned, not weigh over 20 pounds, be completely selfcontained, and be in working order when transported to and operated in the average work place. The response to the development of this nearly nevernever type of instrument has been most impressive. The just published "En­ cyclopedia of Instrumentation for In­ dustrial Hygiene" of the University of Michigan is a book of over 1200 (9 X 12) pages with hundreds of illustrations of such instruments.

N e w e r Chemicals Present Hazards

The field of controlling occupational chemical stress is not a static one. New chemicals are continuously introduced into work environment at a breath1956

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REPORT FOR ANALYSTS taking pace. Many of these are in­ jurious to health at extremely high dilutions in respirable air. Of the numerous insecticides and fungicides developed since World War II, let us consider the organic phosphates parathion and tetraethyl pyrophosphate. Air containing more than 0.1 mg. per cubic meter of parathion cannot be safely breathed by workers for longer than a normal working day; TEPP concentrations must be kept below one half this amount, if nervous system effect is to be avoided. A newcomer to the ever-expanding list of plastic chemicals is toluene diisoeyanate. Air containing more than 0.1 p.p.m. by volume of this chemical is likely to produce severe attacks of bronchial asthma when inhaled in work operations. Beryllium, one of the newer wonder metals, produces serious lung disease in atmospheric concentrations above 1 γ per cubic meter. Development of practical evaluation methods for such substances seriously taxes the analyst's skill, but without such means of measuring atmospheric concentrations, it would be impossible to use these materials. The development of large industrial­ ized centers of urban population with the concomitant discharge of large volumes of chemical waste into the atmosphere has created the new health problem of air pollution. That such pollution can reach levels sufficiently high to cause acute illness and death is now well known. There is strong reason to believe that lower levels of exposure are capable of producing such chronic health impairments as cancer, allergy disease, and anoxia disease due to enzyme inhibition of specific cellular systems. Public health workers are just begin­ ning to tackle this problem and it is indeed a formidab'e one. They first ask the analj'st how much of wrhat chemicals are in the air. A not so jocular reply has been to consult the Beilstein and Gmelin compendiums, because it is possible for most of the compounds therein listed to appear in urban industrial atmospheres. Not only is a tremendous quantity of ma­ terials of unknown composition dis­ charged into the air, but after it is so discharged it enters into secondary chemical reactions which form entirely new materials. It can be said with assurance that the total quantity of chemicals per unit volume is very low. Aerosol concentrations on an obviously dirty day rarely exceed 300 y per cubic meter. Most gaseous impurities are present in amounts below 1 p.p.m. per volume. For any given urban com­ munity, the concentrations of chemicals

in the air are nearly completely de­ pendent on atmospheric or meteoro­ logical conditions which are as changing as the weather. For studies concerning the health effect of air pollution, direct-reading, continuous-recording, continuous-oper­ ating devices are a must. Reason­ ably satisfactory methods are now available for sulfur dioxide, carbon mon­ oxide, ozone, nitrogen dioxide, certain hydrocarbons, soiling power, and radio­ activity. The analytical attack upon the atmosphere is in its infancy. No cause and effect relationship between air pollutants and health can be es­ tablished until a lot more analytical work is done on the specific pollutants in the atmosphere. Consider, for example, the problem of ragweed pollenosis or "hay fever." Now here is an air pollutant which pro­ duces adverse health effects in no un­ certain terms. Parenthetically, few people regard ragweed pollen as an air pollutant, probably because it comes from nature rather than a factory chimney. This emphasis on the factory stack seriously distorts the true nature of the problem. People and nature make air pollution. Industry is a form of people air pollution in a way, but in most urban population concentra­ tions, is not the dominant source. Analytical studies made to date in­ dicate that the industry contribution per se will not exceed 40% of the total and may be as little as 20% or less. Ragweed pollution is also people-made, because it is a pioneer plant which grows best in newly disturbed earth. Very probably a time-concentration relationship exists between atmospheric ragweed pollen and allergy symptoms. No satisfactory analytical method is available for measuring such timeconcentration relationships on a con­ tinuous basis and with a reasonable expenditure of man power. What about the lung cancer problem? Lung cancer is definitely and signifi­ cantly on the increase in urban male populations. Cancer in general is on the increase, especially because the population is living long enough for this chronic disease to develop to the point where it causes sickness and death. The generic cause of cancer is yet unknown, but an impressive and ever-increasing list of chemicals breathed or contacted by workers in their work environments are recognized as increasing the incidence of cancer. Examples are bladder cancer from 2naphthylamine, lung cancer from chro­ mâtes, and skin cancer from 3,4-benzpyrene. Many of these chemicals are present in trace amounts in urban community atmospheres; their contribu-

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REPORT FOR ANALYSTS tion to t h e cancer problem is as yet unknown. An ever-increasing n u m b e r of both old and new chemicals find their w a y into foodstuffs—metals in hydrogenated fats, colorings, flavorings, insecticides. A time-tested staple food product, a loaf of bread, has become within t h e last generation a complex chemical product incorporating synthetic fats, softeners, mold inhibitors, insecticides, fumigants—in fact, a bewildering a r r a y of materials. T h e analytical a t t a c k upon this problem lias been and still is meager. .Publie health workers will eventually have to t u r n increased attention t o t h e m a t t e r of chemical stresses from food and water as well as air.

Summary M a n is designed to withstand chemi­ cal stress up to a certain limit without effect. I t is entirely possible and prac­ tical to define these stresses in q u a n t i ­ tative terms. Likewise it is possible to reduce these stresses to tolerable values when such values are known. I n general, it is n o t possible to reduce stresses t o zero without abolishing t h e use of t h e specific chemical which produces t h e stress. With a d e q u a t e analytical information, it is possible t o evolve standards t h a t will m a k e pos­ sible t h e safe use of a n y chemical. W i t h o u t t h e means for measurement, t h e health problem becomes indeter­ minate. T h e low-level stresses take years to produce their deleterious effect on health. By t h e time t h e effects are noticeable, they are usually irreversible. M e a s u r e m e n t provides t h e industrial hygienist or public, health worker with a veritable crystal ball, wherein which he m a y view t h e effect on a person's health which an environmental chemical stress experienced t o d a y will have a decade or more in t h e future. I t is, of course, t h e work of t h e analyst which has created this crystal ball and it is his future contributions in this most difficult and challenging field which will improve its clarity and accuracy. Beyond question, t h e future health of t h e peoples of this nation and all other nations of t h e industrialized world is critically dependent upon t h e skill and zeal of t h e analyst. I sin­ cerely hope t h a t this presentation will not only result in more analysts turning their attention to this vital area of public interest b u t will in t u r n result in more public recognition and support of t h e deeply buried b u t all-vital con­ tribution of t h e analyst a n d analytical chemistry t o t h e health of t h e nation. ANALYTICAL

CHEMISTRY