The Role of Biological Monitoring in Medical and Environmental

15 T h e R o l e of B i o l o g i c a l

Monitoring

in

Medical

and E n v i r o n m e n t a l Surveillance

Downloaded by NORTH CAROLINA STATE UNIV on January 7, 2013 | http://pubs.acs.org Publication Date: April 2, 1981 | doi: 10.1021/bk-1981-0149.ch015

CARL B. MONROE Corporate Health and Safety, Rohm and Haas Company, Box 584, Bristol, PA 19007 Biological Monitoring is used by environmental engineers to assess the control of workplace exposures to toxicants and by medical personnel to detect medical conditions associated with exposure to these substances. Linch (1) has made an extensive review of techniques that are available for use in biological monitoring. This paper will explore the application of biological monitoring in industrial hygiene and occupational medical surveillance programs, relate biological monitoring to other occupational medical surveillance techniques, and discuss the importance of informing workers of the purpose for the tests and the practical meaning of test results. The approach to occupational health surveillance through biological monitoring is diagramed in Figure 1. Definition of Occupational Biological Monitoring Biological monitoring in occupational health surveillance consists of bioassay or other tests that are administered to workers with known or presumed exposures to potential toxicants in the workplace for the purpose of measuring body uptake of the toxicant, an index of exposure, or detecting pathophysiologic effects of the toxicant, an index of toxicity. Since exposure and toxicity are the determinants of the hazard potential of a toxic substance, the occurrence of either one of these phenomena is reason for preventive health measures. Examples of biological monitoring tests that are applied in environmental and medical surveillance programs are listed in Table I. Application of Biological Monitoring in Environmental and Medical Surveillance The multidisciplinary approach to the evaluation and solution of occupational health problems may involve the use of 0097-6156/81/0149-0223$05.00/0 © 1981 American Chemical Society

In Chemical Hazards in the Workplace; Choudhary, G.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

C H E M I C A L HAZARDS IN T H E W O R K P L A C E

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I d e n t i f y the Problem

Confirm adequate c o n t r o l of exposure ο Measure body uptake of t o x i c a n t Confirm adequate exposure l i m i t ο Determine medical e f f e c t of exposure


Other c o n s i d e r a t i o n s ο I n v e s t i g a t e non-occupational occurrence of t o x i c a n t

II.

Structure B i o l o g i c a l M o n i t o r i n g Program

ο

0

III.

Implement Program

Select b i o l o g i c a l monitoring t e s t Measure the t o x i c a n t o r i t s ο b i o t r a n s f o r m a t i o n products Measure a b i o l o g i c a l response 0 associated with toxicant's mechanism of a c t i o n Formal b i o l o g i c a l m o n i t o r i n g program 0 Purpose of t e s t Schedule of t e s t i n g 0 Method o f a n a l y s i s of t e s t r e s u l t s ο ( c l i n i c a l or epidemiologic) Defined outcome of t e s t r e s u l t s ο ( a l t e r work c o n d i t i o n s , medical removal, e t c * ) Information to be provided t o t e s t ο subjects

Inform worker of purpose of t e s t i n g M e d i c a l personnel conduct

tests

Test r e s u l t s t h a t show medical d i s e a s e s and d i s o r d e r s analyzed by m e d i c a l personnel - Data provided t o environmental engineer without personal i d e n t i f i e r s Test r e s u l t s t h a t show body uptake ( a n a l y s i s f o r t o x i c m a t e r i a l s and nond i s e a s e medical i n d i c e s of exposure) analyzed by environmental engineer Inform worker of t e s t outcome and meaning of t e s t r e s u l t Decide a p p r o p r i a t e course o f a c t i o n

Figure 1.

Flow diagram illustrating the use of occupational biological monitoring



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TABLE I EXAMPLES OF BIOLOGICAL MONITORING TESTS USED IN ENVIRONMENTAL AND MEDICAL SURVEILLANCE

Occupational Exposure

B i o l o g i c a l M o n i t o r i n g Test f o r Body Uptake

B i o l o g i c a l M o n i t o r i n g Test f o r Medical E f f e c t of Exposure

Pb

Blood Pb

Blood Z i n c

CholinesteraseInhibiting Pesticide

Blood L e v e l of P e s t i c i d e or B i o t r a n s f o r m a t i o n Product

Blood C h o l i n e s t e r a s e A c t i v i t y

Cd

Blood and U r i n a r y Cd

U r i n a r y Beta-2 M i c r o g l o b u l i n

D i e s e l Exhaust

E x p i r e d Air-CO

Carboxyhemoglobin measured i n blood or e x t r a p o l a t e d from e x p i r e d air-CO

Protoporphyrin



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a s i n g l e t o o l o r c o n c e p t i n d i s s i m i l a r ways w i t h i n t h e specialty areas ( i n d u s t r i a l hygiene, medicine, etc.) r e p r e s e n t e d on t h e o c c u p a t i o n a l monitoring of a t o x i c a n t or i t s assess

the

integrity

several

h e a l t h team. Biological biotransformation products

o f work p r a c t i c e s ,

engineering

to

controls,


and p e r s o n a l h y g i e n e c a n be u s e f u l i n e n v i r o n m e n t a l surveillance. M e d i c a l s u r v e i l l a n c e programs o f t e n incorporate b i o l o g i c a l m o n i t o r i n g t e s t s to screen f o r h y p e r s u s c e p t i b l e w o r k e r s and t o d e t e c t m e d i c a l c o n d i t i o n s i n t h e e a r l i e s t and most c u r a b l e s t a g e s . The p a r t i c u l a r i t y o f b i o l o g i c a l m o n i t o r i n g i s e v i d e n t i n t h e OSHA p r o m u l g a t i o n on e m p l o y e e a c c e s s t o e x p o s u r e and m e d i c a l r e c o r d s ( 2 ) w h i c h c a t e g o r i z e s b i o l o g i c a l m o n i t o r i n g t e s t r e s u l t s as an e x p o s u r e r e c o r d when t h e a b s o r p t i o n o f a s u b s t a n c e i s m e a s u r e d and as a m e d i c a l r e c o r d when p a t h o p h y s i o l o g i c e f f e c t s a r e d e t e r m i n e d . The r o l e o f b i o l o g i c a l m o n i t o r i n g i n e n v i r o n m e n t a l and m e d i c a l s u r v e i l l a n c e c a n be d i f f e r e n t i a t e d on t h e b a s i s o f t h e p u r p o s e and outcome o f t e s t i n g i n t h e two s i t u a t i o n s . In e n v i r o n m e n t a l s u r v e i l l a n c e , the g o a l of b i o l o g i c a l t e s t i n g is to e v a l u a t e the exposure q u a n t i t y of the h a z a r d p o t e n t i a l posed by a t o x i c s u b s t a n c e . An e n v i r o n m e n t a l s u r v e i l l a n c e p r o g r a m might i n c l u d e the r o u t i n e performance of b i o l o g i c a l t e s t s to d e t e c t body u p t a k e o f w o r k p l a c e c o n t a m i n a n t s t o c o n f i r m t h e effectiveness s u f f i c i e n t by s a m p l i n g . The manufacturing environmental

o f i n d u s t r i a l h y g i e n e p r a c t i c e s t h a t a p p e a r t o be o t h e r measurements, s u c h as a r e a o r p e r s o n a l r o u t i n e a s s e s s m e n t o f u r i n a r y cadmium i n w o r k e r s p l a s t i c s h e e t c o n t a i n i n g cadmium p i g m e n t s when measurements h a v e shown a i r b o r n e cadmium l e v e l s

t o be w e l l w i t h i n a c c e p t a b l e l i m i t s i l l u s t r a t e s t h i s t y p e o f environmental monitoring. A l t e r n a t i v e l y , environmental s u r v e i l l a n c e t h a t i s t a r g e t e d t o work s i t u a t i o n s where t h e r e i s a s i g n i f i c a n t p o t e n t i a l f o r overexposure to a t o x i c m a t e r i a l , e . g . , uranium mining o p e r a t i o n s w i t h h i g h a i r b o r n e concentrations o f u r a n i u m , c a n be e n h a n c e d c o n s i d e r a b l y by b i o l o g i c a l m o n i t o r i n g because b i o l o g i c a l a b s o r p t i o n i s probably t h e b e s t p a r a m e t e r t o show t h e e f f e c t i v e n e s s o f good p e r s o n a l h y g i e n e , h o u s e k e e p i n g , and t h e p r o p e r u s e o f r e s p i r a t o r s or p r o t e c t i v e c l o t h i n g i n t h i s t y p e o f e x p o s u r e s i t u a t i o n . The outcome o f b i o l o g i c a l m o n i t o r i n g i n e n v i r o n m e n t a l s u r v e i l l a n c e i s the d e f i n i t i o n of the e x t e n t to which a t o x i c m a t e r i a l has b e e n a b s o r b e d by t h e b o d y . When n o n - o c c u p a t i o n a l s o u r c e s o f c o n t a m i n a t i o n have been e x c l u d e d , t h i s i n f o r m a t i o n a l l o w s the e n v i r o n m e n t a l e n g i n e e r to judge whether e n v i r o n m e n t a l c o n t r o l measures are

adequate or

need

refinement.

In m e d i c a l s u r v e i l l a n c e , b i o l o g i c a l m o n i t o r i n g i s a p r e v e n t i v e m e d i c a l t o o l t h a t i s u s e d t o d i s c e r n t h e human t o x i c i t y of p o t e n t i a l t o x i c a n t s at exposure l e v e l s present i n the w o r k p l a c e . E v i d e n c e o f human t o x i c i t y c a n r e s u l t f r o m i n d i v i d u a l h y p e r s u s c e p t i b i l i t y , inadequate exposure l i m i t s which might have been d e r i v e d from a n i m a l d a t a , or u n s u s p e c t e d



15.

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excursions i n workplace contamination. Medical monitoring might be done when i n d u s t r i a l hygiene measurements show that a p o t e n t i a l t o x i c a n t i s present i n the workplace at l e v e l s that are considered to be s a f e . The r o u t i n e measurement of blood c h o l i n e s t e r a s e l e v e l s among workers i n w e l l - c o n t a i n e d organophosphate p e s t i c i d e manufacturing operations i s an example. When the workplace i s contaminated w i t h a p o t e n t i a l t o x i c a n t to such an extent that a s i g n i f i c a n t p o t e n t i a l e x i s t s f o r overexposure, b i o l o g i c a l monitoring i s one medical s u r v e i l l a n c e t o o l that can be used to assure that environmental p r o t e c t i v e measures have prevented the occurrence of h e a l t h e f f e c t s . B i o l o g i c a l monitoring of blood c h o l i n e s t e r a s e l e v e l s among f i e l d a p p l i c a t o r s of c h o l i n e s t e r a s e - i n h i b i t i n g p e s t i c i d e s examples t h i s type of monitoring s i t u a t i o n . The outcome of medical monitoring i s the determination of the presence or absence of a medical marker of a t o x i c o l o g i c response to a s p e c i f i c workplace contaminant. The presence of a medical e f f e c t of overexposure leads to medical a c t i o n s aimed to i n t e r r u p t the t o x i c a n t ' s impact upon the worker's h e a l t h . Such medical a c t i o n s i n c l u d e appropriate medical therapy, medical removal p r o t e c t i o n , and medical advisements on the appropriateness of exposure l i m i t s . A p r o p e r l y designed b i o l o g i c a l monitoring program should be developed c o n j o i n t l y by the environmental engineer and medical s t a f f u t i l i z i n g environmental data about the nature of the workplace exposure and medical knowledge about the prevalence of medical c o n d i t i o n s that might a l t e r the s u s c e p t i b i l i t y of i n d i v i d u a l s to the environmental contaminant. The e v a l u a t i o n of the body's uptake of t o x i c a n t s which are done f o r environmental s u r v e i l l a n c e purposes can be used i n c o n j u n c t i o n w i t h medical f i n d i n g s to provide i n f o r m a t i o n on the v a l i d i t y of c u r r e n t assumptions about the human t o x i c i t y of the substance at exposure l e v e l s experienced i n the workplace. In the same manner, medical monitoring y i e l d s i n f o r m a t i o n which the environmental engineer can use along w i t h environmental measurements to judge the adequacy of i n d u s t r i a l hygiene p r a c t i c e s . I t i s e s s e n t i a l to formulate b i o l o g i c a l monitoring programs on the b a s i s of p r i o r environmental i n f o r m a t i o n about known or p o t e n t i a l workplace exposures to t o x i c a n t s s i n c e few m a t e r i a l s are s u f f i c i e n t l y unique to the workplace that b i o l o g i c a l monitoring can be undertaken without p r i o r documentation of the p o t e n t i a l f o r exposure. Assessments of o c c u p a t i o n a l exposure can be confounded by other environmental sources of t o x i c agents. For a metal such as a r s e n i c that can be absorbed from common seafood items i n the d i e t , p o t e n t i a l non-occupational sources should always be considered i n the development of b i o l o g i c a l monitoring programs ( 3 ) · The c o n s u l t a t i v e approach to the design of b i o l o g i c a l monitoring programs can a i d i n the determination of the type of s u r v e i l l a n c e that i s a p p r o p r i a t e . For i n s t a n c e , environmental data showing a c h r o n i c exposure t o Pb might lead to



228

e n v i r o n m e n t a l m o n i t o r i n g w i t h b l o o d Pb l e v e l s monitoring the l a t t e r Pb

( 4 ) , whereas e n v i r o n m e n t a l

intermittent surveillance


acute

and m e d i c a l

for elevated blood zinc protoporphyrin l e v e l s since i s a s e n s i t i v e m a r k e r o f an e x c e s s i v e body b u r d e n o f findings consistent

w i t h low

exposures might r e s u l t i n e n v i r o n m e n t a l w i t h b l o o d Pb l e v e l s a l o n e t o m o n i t o r f o r

overexposures

(_5)·

As shown i n F i g u r e 1, t h e u s e o f b i o l o g i c a l m o n i t o r i n g i n e n v i r o n m e n t a l o r m e d i c a l s u r v e i l l a n c e programs s h o u l d b e g i n w i t h t h e s e l e c t i o n o f a t e s t w i t h an outcome t h a t i s a p p r o p r i a t e to the type of s u r v e i l l a n c e b e i n g conducted. For a d e s i g n a t e d workplace c o n t a m i n a n t , the v a l i d i t y of a b i o l o g i c a l m o n i t o r i n g p r o c e d u r e i s d e p e n d e n t upon (1) t h e s e n s i t i v i t y o f t h e t e s t , the p r o b a b i l i t y t h a t t h e t e s t r e s u l t w i l l be p o s i t i v e when t h e f a c t o r t o be m e a s u r e d i s p r e s e n t ; a n d , (2) t h e s p e c i f i c i t y o f t h e t e s t , t h e p r o b a b i l i t y t h a t t h e t e s t r e s u l t w i l l be n e g a t i v e when t h e f a c t o r t o be m e a s u r e d i s a b s e n t ; a n d , ( 3 ) t h e p r e s e n c e o f t h e p o t e n t i a l t o x i c a n t i n t h e w o r k p l a c e where m o n i t o r i n g i s c o n d u c t e d ; a n d , (4) i n the i n s t a n c e of m e d i c a l m o n i t o r i n g , the absence of o t h e r m a t e r i a l s i n the workplace t h a t might cause the same m e d i c a l e f f e c t t h a t t h e t o x i c a n t i s known t o c a u s e . The u s u a l b i o l o g i c a l m o n i t o r i n g t e s t i s an a s s a y of b i o l o g i c a l s p e c i m e n s (semen ( 6 ) , u r i n e (_3), b l o o d (]_)> and e x p i r e d a i r (8)). In e n v i r o n m e n t a l s u r v e i l l a n c e , a b i o a s s a y d i r e c t e d to the d e t e c t i o n of a s u b s t a n c e or i t s b i o t r a n s f o r m a t i o n product i s the u s u a l t e s t m e t h o d . S k i n s e n s i t i z a t i o n t e s t s (_9), p h y s i o l o g i c a l c h a n g e s i n p u l m o n a r y f u n c t i o n ( 1 0 ) , and c h a r a c t e r i s t i c e f f e c t s o f d u s t s on c h e s t x - r a y s (11) s u p p l e m e n t t h e u s e o f t h e b i o a s s a y i n m o n i t o r i n g f o r e a r l y m e d i c a l m a n i f e s t a t i o n s of exposure to hazardous substances. The j u d i c i o u s u s e o f b i o l o g i c a l m o n i t o r i n g e n t a i l s s c h e d u l e d a d m i n i s t r a t i o n of the t e s t w i t h i n the c o n t e x t

the of the

exposure h i s t o r y . The u s e f u l n e s s o f u r i n a r y c o n c e n t r a t i o n s of h e a v y m e t a l s , s u c h as u r a n i u m , c a n be h i g h l y d e p e n d e n t upon t h e t i m e between t h e c o l l e c t i o n o f t h e s p e c i m e n and t h e l a s t e x p o s u r e ( 1 2 ) . The a s s e s s m e n t o f b l o o d c h o l i n e s t e r a s e levels i s s i m i l a r l y d e p e n d e n t upon t h e t e m p o r a l r e l a t i o n s h i p between t h e a d m i n i s t r a t i o n o f t h e t e s t a n d t h e e x p o s u r e ( 1 3 ) . The d e s i g n a t i o n o f an e x p o s u r e o r m e d i c a l p a r a m e t e r as n o r m a l o r a b n o r m a l c a n be made i n r e l a t i o n s h i p t o t h e i n d i v i d u a l ' s b a s e l i n e s t a t u s 0,JL3) o r i n r e f e r e n c e t o r e s u l t s f r o m a s t a t i s t i c a l l y g e n e r a t e d r e f e r e n c e g r o u p (14,15). T e s t r e s u l t s t h a t show b i o a b s o r p t i o n o f t o x i c a n t s ( e . g . , b l o o d Pb l e v e l s ) o r r e v e a l e a r l y m e d i c a l e f f e c t s o f o v e r e x p o s u r e t h a t do n o t c o n s t i t u t e a d i s e a s e e n t i t y ( e . g . , b l o o d z i n c p r o t o p o r p h y r i n l e v e l s ) c a n be g i v e n t o t h e environmental engineer i n personally i d e n t i f i a b l e form. B i o l o g i c a l monitoring test r e s u l t s that i d e n t i f y a disease state (e.g. , oligospermia) constitute confidential information about the h e a l t h s t a t u s of the i n d i v i d u a l which i s not to be


15.

MONROE

Biological

transmitted

outside the

Monitoring

the

test

for

Surveillance

m e d i c a l department

permission

of

subject.

personally

i d e n t i f i a b l e c o m p i l a t i o n s of

conclusionary

statements

environmental

engineer

so

about that

between w o r k p l a c e e x p o s u r e s

229

without

the

The p h y s i c i a n s h o u l d the

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such data results

as

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and any m e d i c a l e f f e c t s

share well

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the

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discerned. Relationship

of

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among t h e most

valuable

medical surveillance tools. A l t h o u g h g e n e r a l t e s t s o f body system f u n c t i o n , such as r e n a l f u n c t i o n t e s t s ( e . g . , b l o o d u r e a n i t r o g e n ) , a r e done on b i o l o g i c a l s p e c i m e n s and h a v e a r o l e i n m e d i c a l s u r v e i l l a n c e programs f o r o c c u p a t i o n a l exposure to s y s t e m i c t o x i n s (Jj5), t h e s e p r o c e d u r e s d i f f e r q u a l i t a t i v e l y f r o m b i o l o g i c a l m o n i t o r i n g t e s t s which s a t i s f y the f o u r c r i t e r i a described e a r l i e r for v a l i d b i o l o g i c a l monitoring procedures. A b i o l o g i c a l m o n i t o r i n g t e s t s h o u l d be a r e l i a b l e and v a l i d m e a s u r e o f a p a t h o p h y s i o l o g i c change i n c u r r e d by t h e a c t i o n o f a t o x i c s u b s t a n c e upon a s p e c i f i c m e t a b o l i c o r p h y s i o l o g i c pathway. The b i o l o g i c a l r e s p o n s e s h o u l d a p p e a r i n most a l l i n d i v i d u a l s exposed to u n s a f e l e v e l s of the h a r m f u l m a t e r i a l . F o r e x a m p l e , when cadmium i s t h e o n l y h e a v y m e t a l t o w h i c h workers are exposed, the e l e v a t e d u r i n a r y e x c r e t i o n of b e t a - 2 m i c r o g l o b u l i n i n cadmium i n t o x i c a t i o n r e f l e c t s a s e l e c t i v e a c t i o n o f cadmium upon r e n a l h a n d l i n g o f t h i s l o w m o l e c u l a r weight p r o t e i n (17). In t h e a b s e n c e o f e x p o s u r e t o o t h e r h e a v y m e t a l s w h i c h m i g h t c o n f o u n d t h e r e l a t i o n s h i p b e t w e e n cadmium and t h i s b i o l o g i c a l e f f e c t , the use of b e t a - 2 - m i c r o g l o b u l i n d e t e r m i n a t i o n s f o r b i o l o g i c a l m o n i t o r i n g p u r p o s e s i s b a s e d on the r e l a t i v e s p e c i f i c i t y of e l e v a t e d u r i n a r y e x c r e t i o n of t h i s p r o t e i n t o cadmium n e p h r o t o x i c i t y as w e l l as a n e x t r e m e l y h i g h p r e v a l e n c e o f t h i s a b n o r m a l i t y among p e r s o n s o v e r e x p o s e d t o t h i s metal. L i n c h i n c l u d e d p u l m o n a r y f u n c t i o n t e s t s and o t h e r n o n b i o a s s a y p r o c e d u r e s i n h i s compendium o f b i o l o g i c a l m o n i t o r i n g t e s t s (J_8). When a s t r o n g i d e n t i t y e x i s t s b e t w e e n a t o x i c a n t and a m e d i c a l e f f e c t , l a b o r a t o r y p r o c e d u r e s o t h e r t h a n a b i o a s s a y (pulmonary f u n c t i o n t e s t s , chest r a d i o g r a p h s , etc.) c a n be u s e d t o m o n i t o r t h e i n t e r a c t i o n between t h e t o x i c a g e n t and a p a r t i c u l a r p h y s i o l o g i c or m e t a b o l i c system. The d e m o n s t r a t i o n of an a c u t e f a l l i n v e n t i l a t o r y c a p a c i t y a f t e r TDI e x p o s u r e (10) and c a l c i f i e d p l e u r a l p l a q u e s a f t e r a s b e s t o s e x p o s u r e ( 1 1 ) example t h e u s e o f v a l i d n o n - b i o a s s a y p r o c e d u r e s t o monitor b i o l o g i c a l responses to workplace e x p o s u r e s . S i n c e c e r t a i n r e s p i r a t o r y a b n o r m a l i t i e s that are a s s o c i a t e d w i t h e x p o s u r e s t o d u s t s o r o t h e r r e s p i r a t o r y t o x i n s may be e a s i l y c o n f o u n d e d by o t h e r f a c t o r s , s u c h as c i g a r e t t e s m o k i n g ( 1 9 , 20,



230 21 ) ,

the

chest

x-ray

and p u l m o n a r y f u n c t i o n t e s t s

s h o u l d be

u s e d as a b i o l o g i c a l m o n i t o r i n g t e c h n i q u e when an e x p o s u r e t o a r e s p i r a t o r y t o x i n r e s u l t s i n a p a t h o p h y s i o l o g i c response that c a n be r e a d i l y a s c r i b e d t o t h a t m a t e r i a l . The f u l f i l l m e n t o f s i m i l a r c r i t e r i a s h o u l d be met b e f o r e t e c h n i q u e s o t h e r t h a n chest for

radiography

use

or

pulmonary p h y s i o l o g i c t e s t i n g

i n b i o l o g i c a l monitoring

are

adopted

programs.


E c k h a r d t (22) h a s r e m a r k e d t h a t t h e e v o l u t i o n o f b i o l o g i c a l t e s t s to s c r e e n f o r the h y p e r s u s c e p t i b l e worker r e p r e s e n t s one o f t h e i m p o r t a n t p r e v e n t i v e h e a l t h v i s t a s i n occupational health. The d e v e l o p m e n t o f s e n s i t i v e and s p e c i f i c b i o l o g i c a l markers of e a r l y m e d i c a l sequelae of h a r m f u l exposures h o l d s promise to a l l o w the i d e n t i f i c a t i o n of i n a d e q u a t e e x p o s u r e c o n t a i n m e n t and u n s a f e e x p o s u r e l i m i t s b e f o r e i r r e v e r s i b l e impairment of h e a l t h has o c c u r r e d . Medical-Legal

Aspects

of

B i o l o g i c a l Monitoring

i n Medical

Surveillance As w i t h o t h e r m e d i c a l s u r v e i l l a n c e p r o c e d u r e s , t h e r e i s a m e d i c a l - l e g a l r a m i f i c a t i o n to the use of b i o l o g i c a l m o n i t o r i n g in medical s u r v e i l l a n c e . Medical surveillance i s a preventive medical a c t i v i t y that screens for hypersusceptible i n d i v i d u a l s and m o n i t o r s t h e h e a l t h e x p e r i e n c e o f p e r s o n s p r e s u m a b l y e x p o s e d t o s a f e l e v e l s o f s u b s t a n c e s known t o have t h e p o t e n t i a l t o c a u s e d i s e a s e . When s u c h m e d i c a l s u r v e i l l a n c e i s u n d e r t a k e n , t h e r e i s a p r e s u m p t i o n o f a r e l a t i o n s h i p between exposure to the p o t e n t i a l t o x i c a n t f o r which m e d i c a l s u r v e i l l a n c e i s b e i n g done and m e d i c a l c o n d i t i o n s t h a t a r e found to f i t the t o x i c i t y p r o f i l e of the a g e n t . For i n s t a n c e , the d i s c o v e r y of o l i g o s p e r m i a d u r i n g m e d i c a l s u r v e i l l a n c e f o r o c c u p a t i o n a l e x p o s u r e t o d i b r o m o c h l o r o p r o p a n e (DBCP) c o n s t i t u t e s r e a s o n a b l e m e d i c a l e v i d e n c e t h a t e x p o s u r e t o DBCP i s t h e c a u s e o f t h i s m e d i c a l f i n d i n g (6)· Outside the c o n t e x t o f m e d i c a l s u r v e i l l a n c e f o r o c c u p a t i o n a l e x p o s u r e t o DBCP a n d i n t h e a b s e n c e o f an o c c u p a t i o n a l h i s t o r y o f e x p o s u r e t o t h i s a g e n t , the varicocele The

most common c a u s e o f o l i g o s p e r m i a m i g h t or e n d o c r i n e d y s f u n c t i o n .

Informed The

be

a

Worker

necessity

for

the

worker

to

cooperate

i n the

conduct

o f b i o l o g i c a l m o n i t o r i n g p r o c e d u r e s i s e v i d e n t need f o r c o m m u n i c a t i o n t o o c c u r b e t w e e n t h e w o r k e r and t h e o c c u p a t i o n a l h e a l t h p r o f e s s i o n a l c o n d u c t i n g the program. The e x t e n t o f p a r t i c i p a t i o n w i t h i n a w o r k e r p o p u l a t i o n and t h e q u a l i t y o f c o m p l i a n c e among i n d i v i d u a l w o r k e r s m i g h t be e n h a n c e d by i n f o r m i n g p a r t i c i p a n t s o f t h e p u r p o s e o f t h e p r o g r a m and t h e a n t i c i p a t e d u s e o f t h e t e s t r e s u l t s . M o n i t o r i n g t h a t i s done f o r e n v i r o n m e n t a l and m e d i c a l s u r v e i l l a n c e d i f f e r s c o n s i d e r a b l y



15.

MONROE

Biological Monitoring for Surveillance

231

in the meaning of the test result (acceptable exposure vs. unacceptable exposure; normal medical finding vs. abnormal medical finding). Therefore, it is of utmost importance to provide the worker with sufficient information about the program so that the value of participation can be understood and reasonable expectations can be developed about the outcome to be achieved from the test results. In particular, the purpose of biological monitoring procedures that are done to detect potential medical effects of workplace exposures should be discussed with the worker by the physician within the context of the exposure and present medical knowledge about the individual's health. Information about the relationship of the possible outcomes of the test and the meaning for the health of the individual, i.e., reversible or irreversible pathophysiology, should also be disclosed in detail before the biological monitoring activity is begun. Summary Biological monitoring is useful in environmental and medical surveillance activities. Its use in environmental surveillance is to provide the environmental engineer with information about the control of potentially harmful exposures. The function of biological monitoring in medical surveillance is to identify medical effects consequent to such exposures. Biological monitoring entails the bioassay or other measurement of toxicants or biotransformation products and medical markers that are altered by the presence of the toxicant (or its biotransformation products). By virtue of a predictive effect of the toxicant upon the pathophysiologic response measured, biological monitoring tests are among the most desirable of medical surveillance techniques. Because environmental monitoring relates to the matter of exposure and medical monitoring to the occurrence of medical abnormalities consequent to exposure, it is advisable to inform the worker of the purpose of the test that is to be done as well as to indicate beforehand the meaning of potential test outcomes. Acknowledgement Mrs. Lorraine Meyers and Miss Patricia Abbe are thanked for their help in preparing the manuscript. Literature Cited 1. Linch, A. L . , "Biological Monitoring for Industrial Chemical Exposure Control", CRC Press, Inc.: West Palm Beach, FL, 1974.


232

CHEMICAL HAZARDS IN THE WORKPLACE


2.

Final Rule on Access to Employee Exposure and Medical Records, 29 CFR part 1910, Federal Register, 1980, 45, 35212-35303. 3. Schrenk, H. H.; Schreibes, L., Urinary Arsenic Levels as an Index of Industrial Exposure, Am. Ind. Hyg. Assoc. J., 1958, 19, 225-228. 4. Eisinger, J.; Fischbein, Α.; Blumberg, W. E.; Lilis, R.; Selikoff, I. J., Zinc Protoporphyrin in Blood as a Biological Indicator of Chronic Lead Toxication, J. Environ. Pathol. Toxicol., 1978, 1, 897-910. 5. Cavalleri, Α.; Minoia C.; Pozzoli, L.; Baruffini, Α., Determination of Plasma Lead Levels in Normal Subjects and in Lead-Exposed Workers, Br. J. Ind. Med., 1978, 35, 21-26. 6. Whorton, D.; Krauss, R. M.; Marshall, S.; Milby, Τ. Η., Infertility in Male Pesticide Workers, Lancet, 1977, 2, 1259-1261. 7. Wills, J. Η., The Measurement and Significance of Changes in the Cholinesterase Activities of Erythrocytes and Plasma in Man and Animals, CRC Crit. Rev. Toxicol., 1972, 1, 153-202. 8. Breysse, P. Α.; Bovee Η. Η., Use of Expired Air-Carbon Monoxide forCarboxyhemoglobinDetermination in Evaluating Carbon Monoxide Exposures Resulting from the Operation of Gasoline Fork Lift Trucks in Holds of Ships, Am. Ind. Hyg. Assoc. J., 1979, 30, 477-483. 9. Rostenberg, Α.; Bairstow B.; Luther T. W., A Study of Eczematous Sensitivity toFormaldehyde,J. Invest. Dermatol., 1952, 19, 459-462. 10. Wegman, D. H.; Pagnotto, L. D.; Fine, L. J.; Peters J. Μ., A Dose-Response Relationship inTDIWorkers, J. Occup. Med., 1978, 16, 258-260. 11. Edge, J. R., Asbestos Related Disease in Barrow-inFurness, Environ. Res., 1976, 11, 244-247. 12. Lippmann, M.; Ong, L. D. Y.; Harris, D. Β., The Significance of Urine Uranium Excretion Data, Am. Ind. Hyg. Assoc. J., 1964, 25, 43-54. 13. NIOSH Criteria Document for Occupational Exposure to Carbaryl, U.S. Department of Health, Education, and Welfare, September 1976; p.85. 14. Kowal, Ν. E.; Johnson D. E.; Kraemer,, D. F.; Pahren, H. R., Normal Levels of Cadmium in Diet, Urine, Blood, and Tissues of Inhabitants of the United States, J. Toxicol. Environ. Health, 1979, 5, 995-1014. 15. Rider, J. Α.; Hodges, J. L.; Swader J.; Wiggins, A. D., Plasma and Red Cell Cholinesterase in 800 "Healthy" Blood Donors, J. Lab. Clin. Med., 1957, 50, 376-383. 16. NIOSH Criteria Document for Occupational Exposure to Inorganic Mercury, U. S. Department of Health, Education, and Welfare, 1973; p. 2.



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17. Piscator, Μ., Proteinuria in chronic cadmium poisoning 2. The applicability of quantitative and qualitative methods of protein determination for the demonstration of cadmium proteinuria, Arch. Environ. Health, 1962,5, 325-332. 18. Linch, A. L . , "Biological Monitoring for Industrial Chemical Exposure Control", CRC Press, Inc.: West Palm Beach, FL, 1974; p. 4. 19. Krumholz, R. Α.; Chevalier R. B.; Ross, J. C., Changes in Cardiopulmonary Functions Related to Abstinence from Smoking - Studies in Young Cigarette Smokers at Rest and Exercise at 3 and 6 Weeks of Abstinence, Ann. Intern. Med., 1965, 62, 197-207. 20. Weiss, W., Cigarette Smoking and Diffuse Pulmonary Fibrosis, Arch. Environ. Health, 1967, 14, 564-568. 21. Theriault, G. P.; Peters, J. M.; Johnson, W. Μ., Pulmonary Function and Roentgenographic Changes in Granite Dust Exposure, Arch. Environ. Health, 1974, 28, 23-27. 22. Eckardt, R. E., Evaluation of the Worker - Tools and Techniques for the Future, Am. Ind. Hyg. Assoc. J., 1964, 25, 126-132. RECEIVED September

19, 1980.


The Role of Biological Monitoring in Medical and Environmental

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