Inhalation Exposure of Grain Samplers and Grain Inspectors to

15 Inhalation Exposure of Grain Samplers and Grain Inspectors to Carbon Tetrachloride 1,3

2

1

HOWARD M. DEER , CHARLES E. McJILTON , PHILLIP K. HAREIN , and WILFRED SUMNER 1

1

Department of Entomology, University of Minnesota, St. Paul, MN 55108 Department of Environmental Health, University of Minnesota, Minneapolis, MN 55455

Downloaded by UNIV LAVAL on July 11, 2016 | http://pubs.acs.org Publication Date: February 25, 1985 | doi: 10.1021/bk-1985-0273.ch015

2

CCl is a common ingredient of liquid grain fumigant mixtures. Exposure data for this registered use are needed in making regulatory decisions on continuing this registration. USDA's NAPIAP funded research on the CCl4 inhalation exposure of grain samplers and grain inspectors in Minnesota. Ambient concentrations of CCl4 in 7700 grain samples submitted for inspection were determined by colorimetric tube and are an estimator of peak grain inspector exposure to CCl . Concentrations ranged from nondetected to >60 ppm. Significant differences were determined for dates, locations, grain types, and grain transportation vehicles. Approximately 350 8-hour TWA CCl exposures for grain samplers and grain inspectors were determined by using passive dosimeters. All TWA 8-hour exposures were 60 ppm were a s s i g n e d t h e v a l u e o f 100 ppm. T h i s v a l u e was c h o s e n a s t h e c o n c e n t r a t i o n a t w h i c h i n s p e c t o r s would no l o n g e r p e r f o r m t h e " c o f o " t e s t . As r e p o r t e d i n t h e l i t e r a t u r e , t h e o d o r t h r e s h o l d f o r C C l ^ i s b e t w e e n 21 and 100 ppm, w i t h m o s t r e p o r t s i n t h e 5 0 - 8 0 ppm r a n g e . Inspectors i n t e r v i e w e d s t a t e d they would p e r f o r m t h e "cofo" t e s t i f t h e s m e l l o f C C l ^ was n o t e v i d e n t t o s l i g h t i n o d o r s t r e n g t h . The l i t e r a t u r e r e p o r t s t h e o d o r o f C C l ^ t o be s t r o n g a t 176 ppm, so i t was a s s u m e d t h a t i n s p e c t o r s would p e r f o r m t h e " c o f o " t e s t i f t h e odor o f C C l ^ was up t o " s l i g h t " b u t n o t " s t r o n g . " I f t h e mean f o r t h e o d o r t h r e s h o l d i s 64 ppm and t h e o d o r i s s t r o n g a t 176 ppm t h e n i t i s a s s u m e d t o be moderate a t t h e m i d p o i n t , a p p r o x i m a t e l y 120 ppm, and s l i g h t a t

Honeycutt et al.; Dermal Exposure Related to Pesticide Use ACS Symposium Series; American Chemical Society: Washington, DC, 1985.

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approximately one-third of the concentration between the threshold of detection and strong.


Tubes e v i d e n c i n g no CCl^ i n a p a r t i c u l a r sample were used i n subsequent samples u n t i l a reading was determined or a lengthy time i n t e r v a l was to occur, such as lunch time. No tubes were c a r r i e d over to another day. Tubes that showed streaking were recorded as an average between the high and low r e a d i n g s o f the streak. Tubes showing questionable results, such as channeling, were discarded and no reading was recorded. Since grain sample flow was extremely rapid, at times as many as six pumps and tubes were being used at one time. Maximum e f f i c i e n c y was mandatory i n data recording, and tube preparation during these i n t e r v a l s . Lag times were used to check data e n t r y c a r d s , prepare additional tubes, check pumps for a i r leaks, and other a c t i v i t i e s . Data entry cards for each day's t e s t i n g were d e l i v e r e d to the computer services o f f i c e s on the St. Paul Campus o f the University o f Minnesota for entry into a data storage bank, which was s t a t i s t i c a l l y analyzed at completion o f the study period. Objective #3 was accomplished by u t i l i z i n g the c o l o r i m e t r i c tube system to d e t e c t the presence o f C C l ^ i n g r a i n samples to be inspected rather than relying on the olfactory senses of the various i n s p e c t o r s . Previous to t h i s study, CCljj c o n c e n t r a t i o n s i n g r a i n samples were determined by inspectors who detected an odor that they had come to recognize as t h a t o f CCl^. When g r a i n samples to be inspected were checked with a c o l o r i m e t r i c tube, samples t h a t contained CCl^ concentrations could be i d e n t i f i e d before the "cofo" test was performed. Objective #4 was accomplished by selecting and designing a exposure assessment methodology t h a t met the requirements s i m p l i c i t y and cost effectiveness.

CClu or

Results and Discussion M o n i t o r i n g o f g r a i n samples f o r ambient c o n c e n t r a t i o n s o f carbon t e t r a c h l o r i d e and m o n i t o r i n g w o r k p l a c e a t m o s p h e r e s f o r TWA c o n c e n t r a t i o n s o f carbon t e t r a c h l o r i d e were c a r r i e d out i n three Minnesota locations: Minneapolis, Duluth and Mankato. Monitoring was conducted on 7 3 days during the study period of July 14, 1981 through Ocotber 28, 1982. T e s t i n g f o r C C l ^ peak c o n c e n t r a t i o n s i n t h i s r e s e a r c h p r o j e c t was conducted j u s t i n f r o n t o f the performance o f the "cofo" t e s t , because t h i s was the p o i n t at which peak exposure occurred as evidenced by conducting laboratory testing o f job function components with a Miran 1A Infrared Analyzer and the Bendix/Gastec Colorimetric Detection System. This peak determination was made for corn, wheat, rye, o a t s , and b a r l e y , and i n each i n s t a n c e the "cofo" t e s t had the h i g h e s t p o t e n t i a l for CCljj exposure. The second highest p o t e n t i a l for exposure occurred during the opening of the grain sample bag for


232

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c o r n , w h e a t , and b a r l e y and d u r i n g p a s s i n g t h e g r a i n t h r o u g h t h e d o c k a g e m i l l f o r r y e and o a t s . The c o n c e n t r a t i o n r a n g e f o r t h e " c o f o " t e s t was f r o m a p p r o x i m a t e l y 15.5-71*0 ppm on t h e M i r a n 1A I n f r a r e d Analyzer and f r o m a p p r o x i m a t e l y 12->60 ppm o n t h e B e n d i x / G a s t e c C o l o r i m e t r i c Tubes. The range f o r opening the g r a i n s a m p l e b a g f o r c o r n , w h e a t and b a r l e y on t h e M i r a n 1A was f r o m 2.83.0 ppm and on t h e B e n d i x / G a s t e c s y s t e m t h e r e a d i n g s were a p p r o x i m a t e l y 1.5-3.0 ppm. The r e s u l t s f o r p a s s i n g t h e g r a i n t h r o u g h the dockage m i l l was 2 ppm f o r r y e and 5 ppm f o r o a t s . Ambient a i r o f g r a i n s a m p l e s was c h e c k e d a s c l o s e t o , b u t i n f r o n t o f , t h e g r a i n i n s p e c t o r p e r f o r m i n g t h e " c o f o " t e s t ; and t h i s v a l u e i s u s e d a s an e s t i m a t o r o f peak g r a i n i n s p e c t o r exposure. S a m p l e s t h a t c o n t a i n e d h i g h c o n c e n t r a t i o n s (>100 ppm) o f C C l ^ were f r e q u e n t l y d e t e c t e d a t t h e t i m e o f "breakdown." Inspectors c o u l d s m e l l C C l ^ a s s o o n a s t h e y opened t h e c a n v a s and i n n e r p o l y e t h y l e n e bags t h a t h e l d t h e g r a i n sample. These r e l a t i v e l y i n f r e q u e n t samples c o n t a i n e d such h i g h l e v e l s o f C C l ^ t h a t i n s p e c t o r s removed them from t h e i n s p e c t i o n p r o c e s s a t t h a t t i m e and h e l d them out u n t i l t h e odor d i s s i p a t e d t o l e v e l s below d e t e c t i o n by t h e o l f a c t o r y senses. Since t h e l e v e l o f d e t e c t i o n f o r C C l ^ i s about 70 ppm t h e r e was t h e p o s s i b i l i t y t h a t s a m p l e s t h a t had been h e l d o u t because o f e x c e s s i v e CCI4 c o n c e n t r a t i o n s were a l l o w e d back i n t o t h e i n s p e c t i o n p r o c e s s a s s o o n a s t h e i r C C l ^ c o n c e n t r a t i o n had d r o p p e d below t h e 70 ppm t h r e s h o l d o f d e t e c t i o n . R e l i a n c e on t h e o l f a c t o r y sense r e s u l t s i n d e t e c t i o n o f samples c o n t a i n i n g h i g h l e v e l s o f C C l ^ but p r o b a b l y n o t o f samples c o n t a i n i n g c o n c e n t r a t i o n s a t o r above t h e OSHA a c c e p t a b l e c e i l i n g o f 25 ppm and t h e ACGIH STEL o f 20 ppm b u t below t h e odor t h r e s h o l d . When the i n f o r m a t i o n on t h e odor t h r e s h o l d and c o l o r i m e t r i c tube m e t h o d s w e r e d e m o n s t r a t e d t o t h e v a r i o u s i n s p e c t o r s and t h e i r s u p e r v i s o r s , t h e c o l o r i m e t r i c t u b e method was p r e f e r a b l e f o r d e t e c t i n g t h e presence o f C C l ^ c o n c e n t r a t i o n s i n g r a i n samples t o be i n s p e c t e d . I n s p e c t o r s who had been r e l y i n g on C C l n odors as a method o f d e t e c t i o n were shown t h a t s u c h a method was i n a d e q u a t e t o k e e p e x p o s u r e s b e l o w t h e OSHA and ACGHI c e i l i n g s . As a r e s u l t o f t h e e x p l a n a t i o n a s t o why odor t h r e s h o l d d e t e c t i o n was i n a d e q u a t e , t h e i n s p e c t o r s c o u l d u n d e r s t a n d how a more s e n s i t i v e d e t e c t i o n s y s t e m c o u l d reduce t h e i r exposures t o C C l ^ The f r e q u e n c y o f o c c u r r e n c e o f c o n c e n t r a t i o n s o f C C l ^ i n t h e a m b i e n t a i r o f g r a i n s a m p l e s was d e t e r m i n e d ( T a b l e I I I ) . A p p r o x i m a t e l y 87% o f t h e 7,749 samples checked showed no c o l o r i m e t r i c t u b e e v i d e n c e o f C C l ^ w h e r e a s 8.2% e v i d e n c e d 5 ppm and 1.9% 10 ppm C C l ^ c o n c e n t r a t i o n . A l l other c o n c e n t r a t i o n s i n 5 ppm i n c r e m e n t were l e s s t h a n 1% f r e q u e n c y . A p p r o x i m a t e l y 0.5% o f t h e g r a i n s a m p l e s c h e c k e d e v i d e n c e d a c o n c e n t r a t i o n o f C C l ^ >60 ppm, w h i c h was t h e u p p e r l i m i t o f d e t e c t i o n f o r t h e B e n d i x / G a s t e c C o l o r i m e t r i c Tube S y s t e m . T h i s s y s t e m i s NIOSH a p p r o v e d f o r C C l ^ and h a s a + 2 5 % accuracy r a t i n g .


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Table I I I . C C l ^ C o n c e n t r a t i o n s i n Ambient A i r o f G r a i n Samples*

PPM

N

0

6764

87.3

5

632

8.2

10

151

1.9

15

43

0.6

20

31

0.4

25

18

0.2

30

22

0.3

35

7

0.1

40

9

0.1

45

9

0.1

50

10

0.1

55

5

0.1

60

13

0.1

> 60

35

0.5

7749

100.0

%

*Bendix/Gastec C o l o r i m e t r i c

Tubes

The mean C C l ^ c o n c e n t r a t i o n f o r the 7,749 g r a i n samples checked was 1.69 ppm w i t h a s t a n d a r d d e v i a t i o n o f 8.35. The d a t a c o l l e c t e d on a m b i e n t a i r c o n c e n t r a t i o n s o f C C l ^ i n g r a i n s a m p l e s t o be i n s p e c t e d were a n a l y z e d s t a t i s t i c a l l y f o r s i g n i f i c a n t d i f f e r e n c e s between means as r e l a t e d t o l o c a t i o n o f work, t y p e o f g r a i n , t y p e o f g r a i n t r a n s p o r t a t i o n v e h i c l e , and date.


D E R M A L E X P O S U R E R E L A T E D TO PESTICIDE USE

234

Results indicated that Duluth (8.78) had a s i g n i f i c a n t l y higher ppm mean than M i n n e a p o l i s (1.24) or Mankato (0.66) at p=.05 (Table IV).

Table IV.

CC1 CONCENTRATION IN GRAIN SAMPLE AMBIENT AIR BY SAMPLING LOCATION 4


MEAN

S.D. (ppm)

Ν

%

Minneapolis

1.24

6.16

6443

83.1

Mankato

0.66

2.63

781

10.1

Duluth

8.78*

22.32

525

6.8

7749

100.0

* S i g n i f i c a n t l y d i f f e r e n t from other means at p s . 0 5 .

The data also i n d i c a t e d (Table V) t h a t corn (0.64) had a s i g n i f i c a n t l y lower mean than the other tested grains and that oats, rye, and other grains had s i g n f i c a n t l y higher means than barley, corn and wheat a t p=.05.

Table

V.

CCln CONCENTRATION IN GRAIN SAMPLE AMBIENT AIR BY TYPE OF GRAIN S.D.

MEAN

Ν

%

(ppm) Barley

1.69

8.74

1491

19.2

Corn

0.64*

2.96

1853

23.9

Oats

4.24**

17.80

257

3.3

Rye

4.62**

17.24

326

4.2

Wheat

1.84

Other***

4.24**

7.82 17.80

3676 146 7749

47.4 1.9 100.0

-

* S i g n i f i c a n t l y d i f f e r e n t from a l l other means at p=.05. * * S i g n i f i c a n t l y d i f f e r e n t from barley, corn, and wheat means at p=.05. ***Other-Buckwheat, Flax, Sorghum, Soybeans, and Sunflowers.


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inhalation Exposure to CCU

When a n a l y z e d by g r a i n t r a n s p o r t a t i o n v e h i c l e ( T a b l e V I ) , boats had a mean t h a t was s i g n i f i c a n t l y (p=.05) h i g h e r than o t h e r t r a n s p o r t a t i o n v e h i c l e means. A n a l y s i s by date ( T a b l e V I I ) r e v e a l e d a


s i g n i f i c a n t i n c r e a s e i n the f a l l months o f 1981. September (4.7Ό, October (4.20), and December (5.17) 1981 were s i g n i f i c a n t l y d i f f e r e n t from the other means, and August (2.96) 1981 was d i f f e r e n t from other means e x c e p t f o r November (2.44) 1 981 and A p r i l (2.03) 1982. November (2.44) 1981 was d i f f e r e n t from the o t h e r means except f o r August (2.96) 1981 and A p r i l (2.03) and October (1.06) 1982. A p r i l (2.03) 1982 was d i f f e r e n t from the means except f o r J u l y (.96), August (2.96), and November (2.44) 1981 and October (1.06) 1982.

Table VI. CC1 CONCENTRATION IN GRAIN SAMPLE AMBIENT AIR BY GRAIN TRANSPORT VEHICLE 4

MEAN

S.D.

Ν

%

(ppm)

Barge

1.43

5.47

237

3.1

Boat

32.10*

35.68

112

1.4

Boxcar

1.26

8.74

167

2.2

Hopper car

1.21

6.53

5144

66.4

Truck

1.45

5.M0

1826

23.6

Other

.40

2.17

263

3.4

7749

100.0

* S i g n i f i c a n t l y d i f f e r e n t from other means at p=.05.



236

Table VII. CCU CONCENTRATION IN GRAIN SAMPLE AMBIENT AIR BY DATE MEAN

S.D. (ppm)

0.96 7/81 8/81*« 2.96 9/81* 4.71 4.20 10/81* 11/81*** 2.44 12/81* 5.17 1/82 0.78 2/82 0.45 0.76 3/82 4/82****2.03 0.52 5/82 0.20 6/82 0.42 7/82 8/82 1.08 0.50 9/82 10/82 1.06

3.24 7.86 13.23 13.90 11.25 19.40 3.20 1.69 4.59 9.35 1.98 1.09 2.04 4.08 1.93 4.96


DATE

* S i g n i f i c a n t l y d i f f e r e n t from * * S i g n i f i c a n t l y d i f f e r e n t from 11/81 & 4/82 at p=.05. * * * S i g n i f i c a n t l y d i f f e r e n t from 4/82 and 10/82 at p=.05. * * * * S i g n i f i c a n t l y d i f f e r e n t from 11/81 and 10/82 at p=.05.

Ν

%

250 312 450 541 398 464 465 566 810 481 474 490 608 1023 308 109

3.2 4.0 2.8 7.0 5.1 6.0 6.0 7.3 10.5 6.2 6.1 6.3 7.8 13.2 4.0 1.4

other means at p=.05. other means except other means except 8/81, other means except 7/81, 8/81

According to i n f o r m a t i o n s u p p l i e d by the D i v i s i o n o f Grain I n s p e c t i o n , Minnesota Department o f A g r i c u l t u r e , the frequency o f sample c o l l e c t i o n and sample i n s p e c t i o n per employee can be determined. During f i s c a l 1980 the Division of Grain Inspection had 144 samplers t h a t c o l l e c t e d 484,107 samples, o r 3,361 samples per g r a i n sampler. With a p p r o x i m a t e l y 240 work days per year, t h i s i s equal to 14 samples c o l l e c t e d per day f o r each g r a i n sampler. The D i v i s i o n o f Grain I n s p e c t i o n also employed 103 i n s p e c t o r s who i n s p e c t e d 648,656 samples, or 6,297 samples per g r a i n i n s p e c t o r . This i s equal to approximately 26 samples inspected per day for each grain inspector. Therefore, the average grain inspector performs the "cofo" test 26 times per day. During each "cofo" test the inspector inserts h i s nose into the pan o f grain that he i s grading and inhales for 1-2 seconds to check the grain for rancidity, sourness and other o f f odors. The inhaled a i r i s held by the inspector for another 1-2 seconds and then r e l e a s e d . T h i s peak e x p o s u r e p e r i o d l a s t s approximately 3-4 seconds per "cofo" test or on the average from 1-2 minutes in each work day. Determination for 8-hour time weighted averages (TWAs) evidenced a range from nondetected t o 1.88 ppm based on 379 vapor monitor badges. S e n s i t i v i t y ranged from .01 to .09 ppm. The highest reading


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o f 1.88 ppm o c c u r r e d f o r t h e p r i n c i p a l i n v e s t i g a t o r on t h i s r e s e a r c h p r o j e c t . The date was December 22, 1981 a t Mankato when corn samples c o l l e c t e d from hopper c a r s were b e i n g i n s p e c t e d . The second h i g h e s t v a l u e o f 1.61 ppm o c c u r r e d on O c t o b e r 5, 1981 a t M a n k a t o when c o r n samples c o l l e c t e d from hopper c a r s were b e i n g i n s p e c t e d . T h i s badge was a t t a c h e d t o t h e pants c u f f o f t h e dockage m i l l o p e r a t o r . Another badge t h a t was a t t a c h e d t o h i s s h i r t c o l l a r had a c o n c e n t r a t i o n o f 0.15 ppm. The t h i r d h i g h e s t v a l u e o f 1.18 ppm, and a l s o t h e o n l y o t h e r v a l u e above 1 ppm, o c c u r r e d on October 22, 1981 a t Duluth when wheat s a m p l e s c o l l e c t e d f r o m a b o a t b e i n g f i l l e d were b e i n g i n s p e c t e d . T h i s badge was a t t a c h e d t o t h e g r a i n d i v i d e r t h a t samples were passed t h r o u g h j u s t a f t e r c o l l e c t i o n . The b a d g e o n t h e g r a i n s a m p l e r who performed t h i s f u n c t i o n had a c o n c e n t r a t i o n o f 0.075 ppm. On t h i s same day and i n t h i s same l o c a t i o n a badge a t t a c h e d t o t h e pants c u f f o f t h e g r a i n i n s p e c t o r had a c o n c e n t r a t i o n o f 0.25 ppm, a badge a t t a c h e d t o t h e s h i r t c o l l a r o f t h e i n s p e c t o r was 0.055 and an e m p l o y e e d e s i g n a t e d a s t h e r o v e r had a c o n c e n t r a t i o n o f 0.18 ppm. The " r o v e r " moves about w i t h i n t h e g r a i n h a n d l i n g f a c i l i t y c h e c k i n g on a u t o m a t i c s a m p l i n g s y s t e m s and p e r f o r m i n g o t h e r d u t i e s . The r e s e a r c h e r ' s badge on t h i s day had a v a l u e o f 0.70 ppm. M

f l

Other TWA c o n c e n t r a t i o n t h a t were g r e a t e r than 0.5 ppm i n c l u d e d an i n s p e c t o r (0.71 ) i n M i n n e a p o l i s o n A p r i l 2 2 , 1982 who was i n s p e c t i n g o a t s s a m p l e s c o l l e c t e d f r o m h o p p e r c a r s and a g r a i n sampler (0.82) i n D u l u t h on December 13, 1981 who was s a m p l i n g t r u c k s o f wheat. The s a m p l i n g o f t h e wheat was done a u t o m a t i c a l l y and t h e sampler remained i n a s m a l l c i n d e r b l o c k room t o which the sample was p n e u m a t i c a l l y d e l i v e r e d . P e r i o d i c a l l y , he would bag up some o f t h e wheat and send i t on t o an i n s p e c t o r f o r t h e g r a d i n g p r o c e s s . A l l o f t h e o t h e r b a d g e s h a d 8-hour TWA c o n c e n t r a t i o n s o f l e s s than 0.5 ppm. T h i s amount i s a t l e a s t 20 t i m e s below t h e OSHA 8-hour TWA v a l u e o f 10 ppm. ACGIH recommends a T h r e s h o l d L i m i t Value o f 5 ppm and NIOSH recommends a 2 ppm c e i l i n g f o r 1 hour. The 3M #3500 Organic Vapor M o n i t o r i s v e r y s i m p l e i n d e s i g n and f u n c t i o n . I t i s NIOSH a p p r o v e d f o r C C l ^ . Badge p r e p a r a t i o n i s e a s y and i t s u s e d o e s n o t i n t e r f e r w i t h j o b p e r f o r m a n c e . The M i n n e s o t a Department o f A g r i c u l t u r e has l a b o r a t o r y f a c i l i t i e s capable o f a n a l y z i n g t h e s e badges. Badges c o s t about $6 each. Results o f t h i s r e s e a r c h i n d i c a t e w h i c h employees should wear badges based on d a t e , l o c a t i o n , t y p e o f g r a i n , and t y p e o f g r a i n v e h i c l e . The Bendix/Gastec C o l o r i m e t r i c Pump and TUbe method i s e a s i l y u n d e r s t a n d a b l e and f u n c t i o n a l l y s i m p l e . I t i s NIOSH a p p r o v e d f o r CCl^. P r e p a r i n g t h e apparatus t o t e s t f o r C C l ^ i s a l s o easy. Pumps c o s t a p p r o x i m a t e l y $100 each and t h e double tube system c o s t s $4 f o r b o t h t u b e s , o r a p p r o x i m a t e l y $20 f o r a box o f 5 t e s t i n g s y s t e m s . R e s u l t s o f t h i s r e s e a r c h i n d i c a t e w h i c h s a m p l e s have t h e g r e a t e s t p o t e n t i a l f o r C C l ^ p r e s e n c e b a s e d on d a t e , l o c a t i o n , t y p e o f g r a i n , and t y p e o f g r a i n v e h i c l e . These s a m p l e s w o u l d be t h e o n e s t h a t s h o u l d be c h e c k e d m o s t o f t e n , a l t h o u g h c o n t i n u e d random c h e c k i n g would s t i l l be a d v i s e d .


238


Conclusion There was e v i d e n c e o f g r a i n sampler and g r a i n i n s p e c t o r exposure t o c a r b o n t e t r a c h l o r i d e f r o m i t s u s e a s a g r a i n f u m i g a n t b a s e d on t h e r e s u l t s o f c o l o r i m e t r i c tube and p a s s i v e d o s i m e t e r m o n i t o r i n g . Peak exposure f o r the g r a i n i n s p e c t o r o c c u r r e d d u r i n g the c o m m e r c i a l l y o b j e c t i o n a b l e f o r e i g n o d o r " c o f o " t e s t . The a v e r a g e a m b i e n t C C l ^ c o n c e n t r a t i o n p e r s a m p l e was 1.69 ppm. T h e r e were s i g n i f i c a n t d i f f e r e n c e s i n peak exposure p o t e n t i a l s between l o c a t i o n s , by type o f g r a i n , by t y p e o f g r a i n v e h i c l e , and by d a t e .


T i m e W e i g h t e d A v e r a g e (TWA) b r e a t h i n g zone e x p o s u r e s f o r b o t h g r a i n s a m p l e r s and g r a i n i n s p e c t o r s were below 1 ppm. These e x p o s u r e r e s u l t s w e r e w i t h i n t h e l i m i t s o f t h e OSHA s t a n d a r d s f o r TWA, c e i l i n g , and peak e x p o s u r e and t h e ACGIH TLV s t a n d a r d o f 5 ppm. The peak exposures d e t e r m i n e d sometimes exceeded the ACGIH S h o r t Term Exposure L i m i t maximum o f 20 ppm and t h e NIOSH 2 ppm f o r 1-hour c e i l i n g exposure l i m i t . Continued m o n i t o r i n g o f g r a i n s a m p l e s , e s p e c i a l l y D u l u t h b o a t s a m p l e s and r y e and o a t s s a m p l e s and l a t e summer and f a l l ( A u g u s t December) samples, i s recommended.

N o n t e c h n i c a l Summary The i n h a l a t i o n exposure o f Minnesota Department o f A g r i c u l t u r e G r a i n Samplers and G r a i n I n s p e c t o r s t o carbon t e t r a c h l o r i d e from i t s use as a g r a i n f u m i g a n t was s t u d i e d over a 16 month p e r i o d from J u l y 1981 t o October 1982 i n t h r e e l o c a t i o n s ; M i n n e a p o l i s , Mankato, and Duluth. Peak exposures were d e t e r m i n e d by t h e use o f c o l o r i m e t r i c tubes and work d a y e x p o s u r e s were d e t e r m i n e d by u s e o f p a s s i v e d o s i m e t e r s a t t a c h e d t o worker's s h i r t c o l l a r s . Peak exposures o c c u r r e d d u r i n g performance o f t h e c o m m e r c i a l l y o b j e c t i o n a b l e f o r e i g n odor o r " c o f o " , t e s t . The ambient a i r o f a p p r o x i m a t e l y 7,700 g r a i n samples s u b m i t t e d for i n s p e c t i o n were checked by c o l o r i m e t r i c tube and t h e s e v a l u e s a r e i n d i c a t o r s o f peak exposure f o r g r a i n i n s p e c t o r s . A p p r o x i m a t e l y 87% o f t h e s a m p l e s c h e c k e d s h o w e d no e v i d e n c e f o r CClu while a p p r o x i m a t e l y 8% i n d i c a t e d 5 ppm and 2% i n d i c a t e d 10 ppm. One h a l f o f 1% showed a C C l ^ c o n c e n t r a t i o n o f g r e a t e r t h a n 60 ppm w h i c h was the u p p e r l i m i t o f d e t e c t i o n f o r c o l o r i m e t r i c t u b e s y s t e m . The average C C 1 c o n c e n t r a t i o n per sample was 1.69 ppm. 4

Data c o l l e c t e d was a n a l y z e d s t a t i s t i c a l l y f o r s i g n i f i c a n t mean d i f f e r e n c e s according t o l o c a t i o n , type o f g r a i n , type o f grain t r a n s p o r t a t i o n v e h i c l e , and d a t e . D u l u t h was s i g n i f i c a n t l y h i g h e r than M i n n e a p o l i s o r Mankato i n i t s ppm mean per sample. Oats, r y e , and o t h e r g r a i n s (buckwheat, f l a x , sorghum, soybeans, and s u n f l o w e r s ) were s i g n i f i c a n t l y h i g h e r t h a n b a r l e y , c o r n , and wheat. Boats had a s i g n i f i c a n t l y h i g h e r C C l ^ c o n c e n t r a t i o n than barges, b o x c a r s , h o p p e r c a r s , and t r u c k s . The f a l l months o f September, October, and December were s i g n i f i c a n t l y h i g h e r than o t h e r months.


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A l l work day exposures were less than 2 ppm on a time weighted average. Most were l e s s than 1 ppm. The Occupational Safety and Health Administration's (OSHA) time weighted average (TWA) standards i s s e t at 10 ppm, while the American Conference o f Governmental Industrial Hygienists' standard i s 5 ppm and the National Institute for Occupational Safety and Health's standard i s set a 2 ppm f o r 1 hour. The methodology used in t h i s research showed the advantages o f using a system such as the c o l o r i m e t r i c tube r a t h e r than o l f a c t o r y senses f o r d e t e r m i n i n g the presence and c o n c e n t r a t i o n o f C C l ^ i n g r a i n samples. The s i m p l i c i t y and c o s t e f f e c t i v e n e s s o f the methodology makes i t adaptable by the Minnesota Department o f A g r i c u l t u r e f o r continued m o n i t o r i n g o f C C l ^ exposure to g r a i n samplers and grain inspectors.

Acknowledgments This project was supported through the North Central Region Pesticide Impact Assessment Program. Acknowledgment i s given to Tom Krick and Dave Baloga, university o f Minnesota, who conducted the GC-MS vapor monitor analysis.

Literature Cited 1. National Pesticide Information Retrieval System (NPIRS), 1983. 2. "Protection of Environment." Code of Federal Regulations, Chapter 10, 1983. 3. "Ethylene Dibromide; Rebuttable Presumption Against Registration and Continued Registration of Certain Pesticide Products." Federal Register Vol. 42, No. 240, December 14, 1977. 4. "Ethylene Dibromide; Decision and Emergency Order Suspending Registrations of Pesticide Products Containing EDB." Federal Register, Vol. 49, No. 25, February 6, 1984. 5. "Ethylene Dibromide; Intent to Cancel Registrations of Pesticide Products Containing Ethylene Dibromide;..." Federal Register, Vol. 48, No. 197, October 11, 1983. 6. Berck, B. J. Agric. Food Chem., 1974, 22, 977-984. 7. Jagielski, J . ; Scudamore, K.A.; Heuser, S.G. Pestic. Sci.1978, 9, 117-126. 8. Olomucki, E.; Bondi, A. J. Sci. Food Agric. 1955, 6, 592. 9. "Carbon Tetrachloride; Rebuttable Presumption Against Registration and Continued Registration of Certain Pesticide Products." Federal Register. Vol. 45, No. 201, October 15, 1980. 10. Clayton, G.D.; Clayton, F.E. "Patty's Industrial Hygiene and Toxicology,", John Wiley and Sons, New York, 1981; 3472-3478. 11. Hayes, W.J. "Toxicology of Pesticides", The Williams and Wilkins Company, Baltimore, MD 1975. 12. "Criteria For a Recommended Standard - Occupational Exposure to Carbon Tetrachloride." National Institute for Occupational Safety and Health, 1975. 13. Torkelson, T.R.; Hoyle, H.R.; Rowe, V.K. Pest Control, 1966, 6. Honeycutt et al.; Dermal Exposure Related to Pesticide Use ACS Symposium Series; American Chemical Society: Washington, DC, 1985.


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14. Leonardos, G.; Kendall, D.; Barnard, N. J. of Air Pollution, 1969, 19, 91-95. 15. "NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards." National Institute for Occupational Safety and Health, 1981. 16. Smith, P. Lancet 1867, 6, 660-62, 693, 762-63, 791-92. 17. Thomson, W.T. "Agricultural Chemicals - Book III, Miscellaneous Chemicals (Fumigants, Growth Regulators, Repellents, and Rodenticides)," Thomson Publications, Fresno, CA, 1978; p. 8. 18. Britton, W.E. Connecticut Agricultural Experiment Station Report No. 31. 19. Patty, F.A. "Industrial Hygiene and Toxicology," 2nd Edition, Interscience Publishers, New York, 1963; Vol II; p. 1264-1269. 20. Casarett, L.J.; Doull, J. "Toxicology, The Basic Science of Poisons"; Macmillan Publishing Company, New York, 1975; p.472. 21. "Documentation of the Threshold Limit Values for Substances in Workroom Air." American Conference of Governmental Industrial Hygienists, 3rd ed, 1971. 22. Berck, Β. X Int. Congr. Entomol. Proc., 1956, p. 94-104. 23. Berck, B. Canadian Dept. of Agriculture, Publication Number 1004, 1961. 24. Harein, P.K. Unpublished data. "A Review of Fumigant Residues on Grain and Cereal Products as Hazards to Domestic Livestock." Agricultural Experiment Station, University of Minnesota, St. Paul, MN, 1981. 25. Metcalf, C.L.; Flint, W.P. "Destructive and Useful Insects," McGraw-Hill Book Company, New York, 1962; p. 382,383. 26. Storey, C.L.; Martin, C.R.; Sukkestad, D.R. J. Econ. Entomol 1981, 74:188-190. 27. "The Biologic and Economic Assessment of the Pesticide Carbon Tetrachloride." United States Department of Agriculture, (in preparation). 28. Harein, P.K.; Deer, H.M.; Barak, Α., Minnesota Cooperative Ex tension Service, University of Minnesota, St. Paul, MN, 1979. 29. "Farm Use of Minnesota Pesticides 1978." Minnesota Crop & Live stock Reporting Service, St. Paul, MN, 1980. 30. "Pesticides Used on Minnesota Farms in 1980." Minnesota Agri cultural Statistics Service, St. Paul, MN, 1981. 31. "The Use of Pesticides For Stored Grain In Ohio 1980." Ohio Cooperative Extension Service, Ohio State University, Columbus, Columbus, OH, 1982. 32. Heseltine, H.K. Chem. Ind., 1969, 41: 1405-1408. 33. Douglas Chemical Co. "Douglas Tetrafume Weevil Killer and Grain Conditioner", EPA Reg. NO. 1015-10. Liberty, Missouri, 1983. 34. Douglas Chemical Co. "Douglas Tetrakill Weevil Killer and Grain Conditioner, EPA Reg. No. 1015-20. Liberty, Missouri, 1983. 35. Dow Chemical Co. "Vertifume," EPA Reg. NO. 464-188-AA, Midland MI., 1981. 36. Research Products Co."Max Kill High Life Liquid Grain Fumigant," EPA Reg. No. 2548-22. Salina, KS., 1983. 37. Stauffer Chemical Co. "F.I.A. 80-20 Grain Fumigant With SO ," EPA Reg. No. 476-1113. NY, 1983. 38. TH Agriculture and Nutrition Co. "De Pester Fumigant 82 FR," EPA Reg. No. 46946-105. Kansas City, MO., 1983. 2



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39. ΤΗ Agriculture and Nutrition Co. "De Pester Fumigant No. 2," EPA Reg. No. 46946-149. Kansas City, MO., 1983. 40. TH Agriculture and Nutrition Co. "De Pester Super Fumigas," EPA Reg. No. 46946-21. Kansas City, MO., 1983. 41. Vulcan Materials Co. "Vulcan Formula 82-H Grain Fumigant," EPA Reg. No. 5382-6. Birmingham, AL., 1983. 42. Vulcan Materials Co., "Vulcan Terminal Grain Fumigant," EPA Reg. No. 5382-31. Birmingham, AL., 1983. 43. Hayes, Jr., W.J. "Pesticides Studied In Man"; Williams and Wilkins, Baltimore, MD., 1982. 44. "The Federal Insecticide, Fungicide, and Rodenticide Act As Amended." United States Environmental Protection Agency, 1978. 45. "Regulations for the Enforcement of the Federal, Insecticide, Fungicide and Rodenticide Act; Notification to the Secretary of Agriculture of a Proposed Regulation Classifying Certain Uses of Four Pesticide Active Ingredients for Restricted Use." Federal Register, Vol. 48, No. 145, July 27, 1983. 46. "The Official United States Standards for Grain." United States Department of Agriculture, 1978. 47. Bielorai, R.; Alumot, E. J. Agric. Food Chem. 1973, 23, 426-429. 48. Dhaliwal, G.S. J. Food Sci. Technolo. 1974, 12, 1-5. 49. Harein, P.K. Minnesota Cooperative Extension Service, University of Minnesota, St. Paul, MN, 1979. 50. Heuser, S.G. Proc. 1st International Working Conference, 1974. 51. Lindgren, D.L.; Vincent, L.E. J. Econ. Entomol., 1960, 53, 1071-1077. 52. Scudamore, K.A.; Goodship, G. Pestic. Sci., 1982, 13, 149-155. 53. Scudamore, K.A.; Heuser, S.G. Pestic. Sci., 1973, 4, 1-12. 54. Storey, C.L. J. Econ. Entomol., 1971, 64, 227-230 55. "Summary of NIOSH Recommendations for Occupational Health Stan dards." National Institute for Occupational Safety and Health, 1980. 56. "Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment With Intended Changes for 198384." American Conference of Governmental Industrial Hygienists 1983. 57. "NIOSH/OSHA Pocket Guide to Chemical Hazards." National Insti tute for Occupational Safety and Health, 1978. RECEIVED September 16, 1984


Inhalation Exposure of Grain Samplers and Grain Inspectors to

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