ozone chemistry and technology - ACS Publications - American

Toxicity of Ozone SIDNEY MITTLER, MAURICE KING, A N D

BETTY BURKHARDT

Downloaded by UNIV OF ARIZONA on June 8, 2017 | http://pubs.acs.org Publication Date: January 1, 1959 | doi: 10.1021/ba-1959-0021.ch046

Biological Research Section, Armour Research Foundation, Chicago,

Ill.

Repeated exposures to 2.4 p.p.m. by volume of ozone induced some hemorrhage a n d edema in lungs of rats. Adaptation to ozone was noted after 32 hours of accumulated exposure. Twenty per cent of 102 mice died after continuous exposure to 2.4 p.p.m. b y volume of ozone for 24 hours. Chronic exposure to ozone decreased the weight gain of young rats, a n d concentrations greater than 1.2 p.p.m. by volume a n d longer than 7 hours per d a y significantly affected their growth. The 0.1. p.p.m. values as the maximum allowable concentration of ozone for an 8-hour work d a y appears reasonable. O z o n e did not reach or react with the blood of chronically exposed animals. There was no change in hematocrit or hemoglobin values.

W i t h t h e i n c r e a s i n g use of ozone i n i n d u s t r y , t h e presence of a n ozone l a y e r a b o v e 50,000 feet, a n d t h e o c c u r r e n c e of ozone i n s m o g c o n d i t i o n s as i n t h e L o s A n g e l e s a r e a , t h e c h r o n i c t o x i c i t y of t h i s gas h a s b e c o m e a n i m p o r t a n t p r o b l e m . C o n f l i c t i n g r e p o r t s ( 5 , 7) h a v e a p p e a r e d as t o t h e a c t u a l t o x i c i t y of ozone. These d i s c r e p a n c i e s a r e p r o b a b l y d u e t o t h e use of c r u d e ozonizers w i t h h i g h c u r r e n t d e n s i t i e s , m o i s t a i r , t h e use of u n r e l i a b l e m e t h o d s of a n a l y s i s , a n d o r g a n i c m a t e r i a l s r e a d i l y a t t a c k e d b y ozone. I n a n a t t e m p t t o c l a r i f y these d i s c r e p a n c i e s , M i t t l e r a n d c o w o r k e r s h a v e c o n d u c t e d a n e x p e r i m e n t a l p r o g r a m (8). T h e y f o u n d t h a t t h e LD of ozone f o r a 3 - h o u r e x p o s u r e w a s 12.6 p . p . m . b y v o l u m e f o r m i c e , 13.1 p . p . m . f o r r a t s , a n d 24.7 p . p . m . f o r g u i n e a p i g s . A s a c o n t i n u a t i o n of t h i s p r o g r a m , e x p e r i m e n t s w e r e c o n d u c t e d t o d e t e r m i n e t h e p h y s i o l o g i c a l effects of ozone a n d t h e c h r o n i c t o x i c i t y of t h i s gas. 50

T h e ozone c h a m b e r u s e d f o r these e x p e r i m e n t s i s 4 feet w i d e , 7 feet h i g h , a n d 6 feet l o n g ( F i g u r e 1 ) . I t w a s designed t o h o l d a 50-cage a n i m a l r a c k a n d c a n be e a s i l y a d a p t e d f o r use w i t h l a r g e r a n i m a l s . T h e c h a m b e r i s l i n e d w i t h a l u m i n u m sheet t o p r e v e n t u n d u e d e c o m p o s i t i o n of ozone a n d h a s t h r e e w i n d o w s o n e a c h side a n d a s t a n d a r d a l u m i n u m glass d o o r f o r o b s e r v a t i o n a l p u r p o s e s . O z o n e i s m a d e b y d r a w i n g r o o m a i r i n t h r o u g h a C u n e o M i c r o K l e e n filter t o a L e a r - R o m e e o i l p u m p w h i c h compresses t h e a i r t o 10 p . s . i . T h e a i r i s t h e n passed through a L e c t r o d r y e r ( P i t t s b u r g h L e c t r o d r y e r C o r p . , P i t t s b u r g h , P a . ) to be dried. T h i s c l e a n d r y a i r enters t h e W e l s b a c h O z o n a t o r T - 2 3 ( W e l s b a c h C o r p . , P h i l a d e l p h i a , P a . ) , w h e r e t h e ozone is g e n e r a t e d a t a c o n c e n t r a t i o n n e a r 6000 p . p . m . T h e c o n c e n t r a t e d ozone is m i x e d w i t h i n c o m i n g r o o m a i r a t t h e d u c t s h o w n i n the. l o w e r 344

OZONE CHEMISTRY AND TECHNOLOGY Advances in Chemistry; American Chemical Society: Washington, DC, 1959.


MITTLER, KING, A N D

345

BURKHARDT—TOXICITY

Figure 1.

O z o n e chamber for chronic toxicity studies

l e f t - h a n d c o r n e r of F i g u r e 1. A n e x h a u s t f a n p u l l s t h e a i r i n t o , t h r o u g h , a n d o u t of t h e c h a m b e r , w i t h a c o m p l e t e change a b o u t once e v e r y m i n u t e . T h e ozone c o n c e n t r a t i o n i s s a m p l e d a t s i x p o s i t i o n s i n t h e c h a m b e r b y m e a n s of t h e a l u m i n u m t u b e s seen a t t h e r i g h t - h a n d side of F i g u r e 1. T h e c o n c e n t r a t i o n of 2.4 p . p . m . of ozone w a s first selected f o r t h e s t u d y , because t h e a c u t e s t u d i e s h a d s h o w n t h a t definite l u n g d a m a g e o c c u r s a t c o n c e n t r a t i o n s g r e a t e r t h a n 2.4 p . p . m . O n t h e o t h e r h a n d , n o d a m a g e w a s a p p a r e n t a t c o n c e n t r a t i o n s less t h a n 2.4 p . p . m . i n a single e x p o s u r e f o r p e r i o d s u p t o 24 h o u r s . Effects o f C h r o n i c

Exposure

to O z o n e o n

L u n g s of

Rats

T w o 1 0 0 - a n i m a l g r o u p s of 2 - t o 3 - m o n t h - o l d a l b i n o W i s t a r r a t s were u s e d i n t h e c h r o n i c t o x i c i t y tests. G r o u p A w a s exposed t o 2.4 p . p . m . of ozone f o r 4 h o u r s p e r d a y f o r 5 d a y s a week, w h i l e g r o u p Β w a s exposed t o 2.4 p . p . m . f o r 16 h o u r s p e r d a y for 4 days a week. A 10-animal sample f r o m each group was sacrificed after a c c u m u l a t e d exposures of 3 2 , 4 8 , 64, 8 0 , 9 6 , 112, 144, 160, a n d 176 h o u r s . T h e l u n g s were e x a m i n e d v i s u a l l y f o r t y p i c a l o z o n e - i n d u c e d h e m o r r h a g e s . E d e m a w a s assessed b y t h e Joffe (6) m o d i f i c a t i o n of t h e R a h n m e t h o d , b a s e d o n t h e r a t i o of t h e w e i g h t of the l u n g s as r e m o v e d f r o m t h e a n i m a l before a n d a f t e r d r y i n g ( T a b l e I ) . E x p o s u r e t o 2.4 p . p . m . f o r 16 h o u r s p e r d a y 4 d a y s p e r w e e k i n d u c e d l u n g damage. T h e a n i m a l s w h i c h r e c e i v e d t h i s e x p o s u r e s h o w e d severe l u n g d a m a g e a t t h e e n d of 3 2 h o u r s . H o w e v e r , a f t e r t h e t h i r d e x p o s u r e t h e y b e g a n t o r e c o v e r s l i g h t l y , a p p a r e n t l y a d a p t i n g t h e m s e l v e s t o ozone. W h e n t h e a n i m a l s h a d r e c e i v e d


346

A D V A N C E S IN CHEMISTRY SERIES

T a b l e I.

Chronic Toxicity of O z o n e for Albino Rats

a

Lungs Gross Appearance No. of Animals ^Vet/dry weight Edematous Examined Hemorrhagic ratio 16-Hour Exposures to 2.4 P . P . M . by Volume of Ozone , 4 Days per Week 25 4.53° ίό SI 1 SI 10 4.69 1 M 8S 15

ί Exposure îe, Hours


0 32

Day of Autopsy We'd.

48

10

4.65

1 Ν 5 SI 4 M

10 SI

Thurs.

64

10

4.73

3Ν 7 SI 3M

10 SI

Fri.

80

10

4.84

3Ν 7 SI

96

10

4.69

112

10

128

7 SI 3M

Tues.

2 Ν 7 SI 1 M

10 SI

Wed.

4.65

1 Ν 7 SI 1 M

10 SI

Thurs.

10

4.81

1 Ν 8 SI 1 M

8 SI 2M

144

10

4.70

1 Ν 9 SI

7 SI 2M 1 S

Tues.

160

7

4.72

7 SI

1 Ν 5 SI 1 M

Wed.

176

6

4.58

2Ν 4SI

6 SI

Thurs.

0 32

Fri.

4-Hour Exposures to 2Λ P . P . M . by Volume of Ozone, 5 Days per Week 25 4.53 10 Ν 10 4.76 10 Ν

d

Mon. Fri.

48

10

4.78

9Ν 1 SI

10 Ν

64

10

4.75

9Ν 1 SI

8Ν 2 S1

Thurs.

80

10

4.G8

9 Ν 1 SI

7Ν 3 S1

Wed.

96

10

4.74

10 Ν

6Ν 3 S1 1 S

Tues.

112

10

4.63

9 Ν 1 S1

9 Ν 1 S1

Mon.

128

10

4.62

9Ν 1 S1

8Ν 2 S1

Fri.

144

10

4.64

10 Ν

9 Ν 1 S1

Thurs.

160

7

4.59

7 Ν

6 Ν 1 S1

Some deaths occurred during exposure: 1 after 64 hours, 3 during 80- to 96-hour exposure, 1 after 128 hours, 1 during 128- to 144-hour exposure. Ν Normal, SI slight, M moderate, S severe. Standard deviation for controls 0.104. Some deaths occurred during experiment: 1 after 64 hours, 1 after 92 hours, 1 after 108 hours, and 1 after 132 hours. a

b c

d

a

total

of 6 4 h o u r s of e x p o s u r e , t h e y h a d r e a c h e d a p l a t e a u o f t h e e x t e n t o f

damage w h i c h was maintained u n t i l the

3-day

prevented

nonexposure further

t h e e n d of t h e e x p e r i m e n t .

period plus the acclimatization

increase

i n lung

damage.

These

to repeated results

lung

I t is possible

agree

ozone with


that

exposure those

of

MITTLER

#

KING, A N D

347


S t o k i n g e r , W a g n e r , a n d W r i g h t (10), w h o r e p o r t e d t h a t a 4 - t o 6-week t o l e r a n c e t o ozone w a s d e v e l o p e d f r o m a single 6 - h o u r e x p o s u r e t o 1 p . p . m . of ozone. I n t h e e x p e r i m e n t w i t h r e p e a t e d 4 - h o u r exposures a t 2.4 p . p . m . d a m a g e t o t h e r e s p i r a t o r y s y s t e m w a s n o t v i s i b l e u n t i l a f t e r 64 h o u r s of c u m u l a t i v e e x p o s u r e . Even a f t e r t h e c u m u l a t i v e e x p o s u r e t o ozone of 144 h o u r s i n t h e 4 - h o u r i n t e r v a l e x p e r i m e n t , t h e r e w a s less d a m a g e t h a n a t t h e 4 8 - o r 6 4 - h o u r p e r i o d i n t h e 1 6 - h o u r e x p o s u r e series. T h e animals w h i c h s u r v i v e d i n the 4-hour exposure experiment appeared to become r e s i s t a n t a n d s h o w e d o n l y s l i g h t d a m a g e t o t h e r e s p i r a t o r y t r a c t . O n e of t h e c o n c l u s i o n s r e a c h e d w a s t h a t t h e w e t - d r y r a t i o of t h e l u n g s i s n o t s i g n i f i c a n t as a m e t h o d f o r assessing l u n g d a m a g e i n a n i m a l s exposed t o l o w c o n c e n t r a t i o n s of ozone. During t h e e x p o s u r e t o 2.4 p . p . m . t h e gross a p p e a r a n c e g a v e m o r e i n f o r m a t i o n t h a n t h e e d e m a m e t h o d of Joffe.


Effects o f C o n t i n u o u s

E x p o s u r e to O z o n e o n S u r v i v a l

of

Mice

T h e d a t a o n c o n t i n u o u s e x p o s u r e of 102 m i c e t o 2.4 p . p . m . of ozone f o r 241 h o u r s i n d i c a t e t h a t a t t h i s l e v e l t h e e x p o s u r e w a s f a t a l t o 2 0 % of t h e t o t a l n u m b e r of e x p o s e d a n i m a l s ( T a b l e I ) . A t t h e e n d of 96 h o u r s , 8 . 8 % of t h e a n i m a l s e x p o s e d were Table II. Survival of 102 Mice during Continuous Exposure to 2.4 P.P.M. by Volume of O z o n e Exposure, Hr. 98 124 146 170 241 241* a

No. of Survivals 93 92 91 90 87 81

Dead, % 8.8 9.8 10.8 11.8 14.7 20.6 a

Total dead 7 days after exposure.

d e a d . T h e s e d a t a d o n o t a p p e a r t o agree w i t h t h e r e p o r t of S t o k i n g e r a n d associates (10) t h a t t h e L D f o r m i c e is 4.8 p . p . m . of ozone f o r 4 h o u r s . R e c e n t l y , D i g g l e a n d G a g e (3) r e p o r t e d t h a t t h e LD f o r ozone f o r m i c e a t a 4 - h o u r e x p o s u r e is 10 to 12 p . p . m . b y v o l u m e . 5

0

50

T h e d a t a agree s o m e w h a t w i t h t h e r e s u l t s r e p o r t e d b y M i t t l e r a n d associates (8), i n w h i c h t h e LD w a s f o u n d t o b e 12.6 p . p . m . f o r a 3 - h o u r e x p o s u r e . These differences m a y be a t t r i b u t e d t o t h e a n a l y t i c a l m e t h o d s u s e d i n d e t e r m i n a t i o n of t h e ozone. S t o k i n g e r a n d h i s colleagues u s e d a m o d i f i c a t i o n (2) of t h e S m i t h - D i a m o n d m e t h o d (9) ; D i g g l e a n d G a g e u s e d t h e n e u t r a l p o t a s s i u m i o d i d e m e t h o d of G l u c k a u f a n d associates (4). T h e a l u m i n u m c h l o r i d e m o d i f i c a t i o n of t h e p o t a s s i u m i o d i d e m e t h o d of T h o r p (11) w a s u t i l i z e d t h r o u g h o u t t h i s s t u d y . I f i t c a n b e a s s u m e d t h a t t h e ozone p r o d u c e d b y e a c h i n v e s t i g a t i o n is u n c o n t a m i n a t e d a n d i f t h e LD is t h e n u s e d as a y a r d s t i c k , one c a n c o n c l u d e t h a t t h e S m i t h - D i a m o n d m e t h o d i n w h i c h t h e s p e c t r o p h o t o m e t r i c d e t e r m i n a t i o n i s m a d e of t h e i o d i n e released a f t e r a c i d i f i c a t i o n y i e l d s a n ozone a n a l y s i s 2 % t i m e s l o w e r t h a n t h e n e u t r a l o r a c i d - b u f f e r e d p o t a s s i u m iodide-sodium thiosulfate method. 50

50

Effect o f R e p e a t e d D a i l y E x p o s u r e to L o w C o n c e n t r a t i o n o f O z o n e o n W e i g h t G a i n o f Y o u n g Rats Y o u n g m a l e a l b i n o W i s t a r s t r a i n r a t s ( a v e r a g i n g a b o u t 50 g r a m s ) w e r e e x p o s e d t o ozone 5 d a y s a w e e k f o r v a r i o u s l e n g t h s of t i m e p e r d a y f o r 4 w e e k s . T h e a n i m a l s w e r e w e i g h e d a t w e e k l y i n t e r v a l s a n d a t t h e e n d of t h e 4 - w e e k p e r i o d t h e t o t a l g a i n i n w e i g h t of t h e a n i m a l s w a s d e t e r m i n e d . T a b l e I I I s u m m a r i z e s t h e results of t h e e x p e r i m e n t a l d a t a a n d t h e s t a t i s t i c a l t r e a t m e n t . T o c h a r a c t e r i z e f u l l y t h e d a t a , a n e m p i r i c a l e q u a t i o n w a s d e r i v e d t o r e l a t e t h e difference i n w e i g h t g a i n t o

American Society OZONE CHEMISTRYChemical AND TECHNOLOGY Advances in Chemistry; American Chemical Society: Washington, DC, 1959. Library

A D V A N C E S IN CHEMISTRY SERIES

348

Table III.

Summary of Statistical Analysis of Weight G a i n of Rats Exposed to O z o n e 5 Days/Week, 4-Week Ί reatment

Expt. Group I 1 2 3 II 4 δ 6 III 7 8 IV 9 10 11 12 V 13 14 a


b

P.P.M. 1.2 0.6 Control 1.2 2.4 Control 1.2 Control 1.8 1.8 1.2 Control 0.6 Control

No. of Ani Hr./day mals 7 46 16 45 A 48 3 43 3 51 Β 49 16 47 C 43 7 20 3 20 11.5 20 D 20 10 29 Ε 21

Resid ual Stand Resid Stand ard ard Error of ual Variance Deviation Mean 2.31 15.66 245.26 368.74 19.19 2.88 282.72 16.80 2.43 271.57 16.47 2.51 425.76 20.62 2.89 372.35 19.29 2.75 436.39 20.89 3.05 230.66 15.17 2.31 146.89 12.12 2.56 75.61 8.70 1.93 168.32 12.97 2.90 70.76 8.41 1.88 279.96 16.70 3.12 387.19 19.70 4.30

Mean Weight Gain, G . 178.00 176.73 191.00 181.40 151.39 184.06 150.87 192.98 196.55 207.85 198.00 217.35 184.00 197.60

95% Confi dence Limits ±4.66 ±5.81 ±4.86 ±5.70 ±5.78 ±5.50 ±6.10 ±4.66 ±5.35 ±4.03 ±6.06 ±3.92 ±6.39 ±8.96

t

yc-y»*

13.00 14.27

3.91 3.68

2.66 32.67

0.96 7.90

42.11

11.08b

20.80 9.50 19.35

6.46b 3.60 5.77b

13.60

2.74b

h b

b

h

Mean gain of controls minus mean gain of exposed in grains. Significance at 99% level.

t h e ozone c o n c e n t r a t i o n a n d t h e n u m b e r of h o u r s of e x p o s u r e p e r d a y . T h e e q u a t i o n u t i l i z e d t h e f a c t t h a t w h e n e i t h e r t h e t i m e of ozone exposure o r t h e ozone c o n c e n t r a t i o n is zero, t h e w e i g h t difference is also zero Υ =

(bo + bixi +

ΧΛΧΙ

te )

(I)

2

w h e r e Y i s t h e difference i n w e i g h t g a i n b e t w e e n t h e c o n t r o l g r o u p a n d t r e a t e d g r o u p , x i s t h e ozone c o n c e n t r a t i o n , x is t h e t i m e of e x p o s u r e , a n d b b and b are c o n s t a n t s . T h e m e t h o d of least squares w a s u s e d t o e s t i m a t e t h e v a l u e of t h e c o n s t a n t s f r o m t h e e x p e r i m e n t a l r e s u l t s of t h e first 12 g r o u p s ±

2

0)

Y = X1X2 (-1.126488 + 0.6887692 x + 0.06514642 .τ ) l

2

ly

2

(2)

F r o m E q u a t i o n 2 a series of v a l u e s of Y f o r v a r i o u s c o m b i n a t i o n s of ozone c o n c e n t r a t i o n s a n d exposures r a n g i n g f r o m 1 t o 20 h o u r s a n d 0 t o 3 p . p . m . w a s d e t e r m i n e d with the digital computer. F i g u r e 2 is a g r a p h of t h e difference i n w e i g h t g a i n p l o t t e d a g a i n s t e x p o s u r e t i m e f o r a series of c o n s t a n t ozone c o n c e n t r a t i o n s a n d F i g u r e 3 shows t h e w e i g h t g a i n difference p l o t t e d a g a i n s t ozone c o n c e n t r a t i o n f o r a series of c o n s t a n t exposures. F r o m t h e e x p e r i m e n t a l a n d c a l c u l a t e d r e s u l t s t h e t o l e r a n c e l i m i t s of e x p o s u r e of r a t s t o ozone m i g h t b e d e t e r m i n e d , as s h o w n b y t h e f o l l o w i n g t w o e x a m p l e s . 1. I f a difference i n w e i g h t g a i n of c o n t r o l a n d t r e a t e d r a t s of 10 g r a m s is t a k e n as t h e p o i n t w h e r e i n j u r y occurs, w i t h reference t o F i g u r e 2, t h e f o l l o w i n g c o m b i n a t i o n s f o r a 5 d a y s p e r w e e k e x p o s u r e f o r 4 weeks a r e o b t a i n e d : 2.4 p . p . m . f o r 1.5 h o u r s , 1.8 p . p . m . f o r 3 h o u r s , 1.2 p . p . m . f o r 7 h o u r s , a n d 0.6 p . p . m . f o r 16 h o u r s . 2. I f a 1 5 - g r a m difference i s u s e d as t h e p o i n t w h e r e i n j u r y occurs, t h e f o l l o w i n g c o m b i n a t i o n s a r e o b t a i n e d : 2.4 p . p . m . f o r 2 h o u r s , 1.8 p . p . m . f o r 4 h o u r s , 1.2 p . p . m . f o r 9 h o u r s , a n d 1 p . p . m . f o r 19 h o u r s . B e l o w these l i m i t s i t m i g h t be a s s u m e d t h a t a y o u n g g r o w i n g r a t c o u l d r e m a i n i n ozone a t m o s p h e r e w i t h o u t d e l e t e r i o u s effects. T h e s e e x p e r i m e n t a l r e s u l t s c o n c u r w i t h m a x i m u m a l l o w a b l e c o n c e n t r a t i o n v a l u e of ozone o f 0.1 p . p . m . f o r a n 8 - h o u r d a y , a d o p t e d b y t h e A m e r i c a n C o n f e r e n c e of G o v e r n m e n t a l I n d u s t r i a l H y g i e n i s t s i n 1955 (1). H o w e v e r , i t i s v e r y d i f f i c u l t t o d e t e r m i n e ozone r e l i a b l y b e l o w 1 p . p . m . A s t h e o d o r of ozone c a n b e r e a d i l y d e t e c t e d b e l o w 0.1 p . p . m . (12), t h e r u l e u t i l i z e d i n these l a b o r a t o r i e s is t o m a i n t a i n v e n t i l a t i o n so t h a t t h e o d o r of ozone c a n n o t b e p e r c e i v e d . T o d e t e r m i n e w h e t h e r t h e a m o u n t s of f o o d c o n s u m e d b y o z o n i z e d a n d c o n t r o l a n i m a l s were different, t w o g r o u p s of y o u n g r a t s w e r e u s e d . O n e g r o u p w a s p l a c e d i n t h e ozone c h a m b e r a n d g i v e n a n e x p o s u r e of 2.4 p . p . m . f o r 3 h o u r s d a i l y f o r 4 weeks. T h e o t h e r g r o u p w a s m e r e l y p l a c e d i n t h e c h a m b e r a n d exposed t o a i r f o r




0/

φ Δ , O, •

349


Calculated values Experimental data * Weight gain of control rats minus weight gain of exposed rats

t h e same p e r i o d of t i m e . T h e f o o d c o n s u m p t i o n a n d w e i g h t g a i n were t a b u l a t e d f o r b o t h g r o u p s ; a n a n a l y s i s of v a r i a n c e of t h e d a t a f r o m t h e t w o g r o u p s i s p r e s e n t e d i n Table I V . Table IV.

Group Exposed* Control

1

Relationship between Food Intake and Adjusted Weight G a i n No. of Rats 17 18

Mean Food Intake, G . 468.1 524.4

Dev. from Exptl. Mean Intake, G . -29.0 27.3

Mean Weight Gain, G . 132.8 101.0

Adjusted* 139.90 154.51

Variance Ratio, F 37.71

Experimental mean food intake = 497.1 grams Regression coefficient = 0.2451 gram per gram of food * y = y — bx, where y = adjusted mean gain, b = regression coefficient, and χ = mean food intake. 2.4 p.p.m. or 3 hr. per day for 5 days per week, for 4 weeks. b

W h e n t h e m e a n g a i n i n w e i g h t of b o t h g r o u p s is a d j u s t e d t o a c o m m o n f o o d i n t a k e , a h i g h l y s i g n i f i c a n t F v a l u e of 37.7 i s o b t a i n e d , w h i c h i n d i c a t e s t h a t t h e q u a n t i t y o f f o o d c o n s u m e d does n o t e x p l a i n t h e difference i n w e i g h t g a i n of t h e t w o


A D V A N C E S IN


350

OZONE CONCENTRATION,

CHEMISTRY SERIES

PÇM

Figure 3 . Effect of ozone concentration upon the weight gain of young rats with exposure time constant A/

•/

0/

φ Ο

Calculated values Experimental data * Weight gain of control rats minus the weight gain of posed rats

ex

g r o u p s . I t a p p e a r s t h a t a n i m a l s e x p o s e d t o ozone d i d n o t u t i l i z e the f o o d e a t e n as efficiently as t h e c o n t r o l s . Effect o f

O z o n e on

Blood

T h e p r o b l e m of w h e t h e r ozone i t s e l f reaches a n d reacts w i t h t h e b l o o d w a s s t u d i e d . E a r l i e r i n v i t r o studies h a d s h o w n t h a t ozone does n o t o x i d i z e t h e f e r r o u s i o n of o x y h e m o g l o b i n t o t h e f e r r i c i o n t o p r o d u c e m e t h o m o g l o b i n w h e n 39.6 p . p . m . is b u b b l e d a t a r a t e of 150 m l . p e r m i n u t e d i r e c t l y i n t o w h o l e b l o o d . Ozonized plasma, o n t h e o t h e r h a n d , s h o w e d a definite increase i n a b s o r b a n c e a t 250, 280, a n d 350 πΐμ ( T a b l e V ) . C o n s e q u e n t l y , b l o o d p l a s m a f r o m 27 y o u n g r a t s e x p o s e d t o 2.4 p . p . m . of o z o n e f o r 3 h o u r s p e r d a y , 5 d a y s p e r w e e k f o r 8 weeks, a n d t w o a n i m a l s e x p o s e d t o a n a c u t e dose of 40 p . p . m . of ozone f o r 3 h o u r s a n d 20 m i n u t e s w a s examined spectrophotometrically. T h e a b s o r b a n c e s o b t a i n e d d i d n o t differ s i g n i f i c a n t l y f r o m those o b t a i n e d f o r p l a s m a f o r 30 c o n t r o l a n i m a l s . T h e hemoglobin content a n d hematocrit values were determined o n the b l o o d




Table Y.

351

Effect of Ozonization on Absorbance of Rat Blood Plasma Wave Length, Μμ

Plasma* Ozonized* Control

250 0.57 0.29

280 0.71 0.53

350 0.155 0.031

» 1:100 0.066 M phosphate buffer. 30.10 p.p.m. Oa for 15 min. at 250 ml./min.


b

f r o m 3 1 y o u n g r a t s e x p o s e d t o 2.4 p . p . m . of ozone f o r 3 h o u r s p e r d a y , 5 d a y s p e r w e e k f o r 8 w e e k s . T h e a v e r a g e h e m o g l o b i n c o n t e n t f o r 2 7 c o n t r o l r a t s w a s 14.6 a n d 14.9 g r a m s p e r 100 m l . f o r t h e e x p o s e d r a t s . T h e a v e r a g e h e m a t o c r i t w a s 4 6 . 8 % f o r t h e c o n t r o l s a n d 4 7 . 8 % f o r t h e e x p o s e d r a t s . B o t h sets of v a l u e s f a l l w i t h i n t h e n o r m a l ranges f o r r a t s . T h e r e f o r e , i t i s c o n c l u d e d t h a t ozone does n o t r e a c h t h e b l o o d of a n i m a l s t h a t h a v e b e e n c h r o n i c a l l y e x p o s e d t o o z o n e . I t a p p e a r s t h a t t h e ozone r e a c t s w i t h t h e i n n e r s u r f a c e of t h e r e s p i r a t o r y t r a c t a n d d e c o m p o s i t i o n o c c u r s before i t c a n enter t h e blood stream. Acknowledgment T h e a u t h o r s a r e g r a t e f u l t o H . G . C l a m a n n , S c h o o l of A v i a t i o n M e d i c i n e , U S A F , for his continuous advice, F . C . B o c k , the A r m o u r Research F o u n d a t i o n , for a i d i n s t a t i s t i c a l a n a l y s i s of t h e e x p e r i m e n t a l d a t a , a n d R o b e r t B r a b e t s f o r e n g i n e e r i n g d e s i g n o f t h e ozone c h a m b e r . Literature

Cited

(1) American Conference of Governmental Industrial Hygienists, Arch. Ind. Health 11, 521 (1955). (2) Byers, D. H., Saltzman, B. E., Hyslop, F. L., Final Report of Environmental Research Laboratory, Dept. of Public Health, School of Medicine, Univ. of Washington, 1955. (3) Diggle, W. M., Gage, J. C., Brit. J. Ind. Med. 12, 60 (1955). (4) Gluckauf, E., Head, H. G., Martin, G. R., Paneth, F. Α., J. Chem. Soc. 1944, 1. (5) H i l l , Ε. V., Intern. Eng. 82, 101 (1942). (6) Joffe, M. H., Science 120, 612 (1954). (7) McDonnell, Η. B., Sci. American 155, 283 (1936). (8) Mittler, S., Hedrick, D., K i n g , M., Gaynor, Α., Ind. Med. Surgery 25, 301 (1956). (9) Smith, R. G., Diamond. P., Am. Ind. Hyg. Quart. 13, 235 (1952). (10) Stokinger, Η. E., Wagner, W. D., Wright, P. G., Arch. Ind. Health 14, 158 (1956). (11) Throp, C. E., "Bibliography of Ozone Technology," V o l . 1, p. 209, Armour Research Foundation, Chicago, 1954. (12) Witheridge, W. N., Yaglou, C. P., Ice and Rejrig. 97, 78 (1939). RECEIVED for review June 6, 1957. Accepted June 19, 1957. Study supported by funds provided under contract AF 18(600)-944 with the USAF School of Aviation Medicine, Randolph Field, Tex.


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