Document jz2NzGdeLXaxvGdj9vQJMNBN

POSSIBILITIES OF CONTROL OF LEAD EXPOSURE BY EXAMIN ING LESS THAN 24 HOUR URINE SAMPLES* E. C. Ba r n e s . Industrial Engineer, Medical Department, Weslinghouse Electric and Manufacturing Company, East Pittsburgh, Pa. T has been shown by Kehoe and tween short time or instantaneous I others (1) that the urinary lead specimens and average 24 hour excreexeretion per day is definitely re- tion since the ability to collect smaller lated to the amount of lead entering specimens in the Medical Department the system. The higher the lead in* take, the higher the total lead excretion per day' and correspondingly the higher the lead concentration in the would eliminate most of the difficulties encountered. After discussing the problem with various persons it was felt that some correlation might be urine. Assuming that the urinary obtained if factors such as time of day, volume per day is somewhere near -acidity, specific gravity or total nitro- constant, either the per day excretion or the concentration of lead may be used as an index of exposure. Most of this work has been based gen were taken into account. Several spray painters consented to assist in this study. Each person came to the Medical Department several times on the examination of 24 hour or during the working day so that indilonger specimens of urine. These long vidual instantaneous specimens could time samples have been used to aver- be collected under supervision. The age out the wide variations in lead urine passed during the evening and concentration in the urine which occur morning was collected as another sin- at different times in the day and on. gle sample in a special container which successive days. For some time our was taken home by the man. The Medical Department has used 24 hour lead concentration in each specimen specimens as a measure of lead exposure of persons doing spray painting and working with lead or lead compounds. Considerable difficulty has was determined using the dithizone titrimetric extraction procedure (2, 3), the analyses being made by a chemist experienced in this method. Other arisen in this program because of con- factors were measured such as specific tamination of the containers, failure gravity, pH, nitrogen by Doremus- of employes to take containers home Hinds ureometer and total urine at night, forgetting to use the eon- volume. Three men who have some tainers and difficulty of mailing or lead exposure were studied for 2 days- shipping the specimens. or longer- and 2 persons not exposed to An investigation was undertaken to lead industrially were studied for 5 attempt to get some correlation be- days and 2 days each. A tabulation * Received for publication June 10, 1939. of these data did not show a good 464 N36932 DUP050312923 Nov. 1939] LEAD IN URINE 465 correlation between lead concentration Another possibility was then conand any of the other factors measured, sidered, namely, that the lead excre- TABLE I Ur in a r y Le a d Ex c r e t io n URINE&AVXLB 23,0. l 2* 3 4 5* 6 LEAD mu./I. .00 .13 .24 .26 .15 .13 SP. 61). PH NITROGEN Subject A (spray painter) 1.008 1.019 1.021 l'.026 1.018 1.019 5.3 5.2 , . 5.3 5.0 6.6 5.1 mg./cc. 14 13 12 14 13 11 URINE [ LEAD' -|------- . -- - co./hr. 55 42 18 26 38 55 y/hr. 5.0 5.5 4.3 6.8-----5.7 7.1 jMax. var............... .143 +82% -37% 5.61 +27% --23% Subject B (spray painter) 1 . 2* 3 4 5* 6 7 .32 1.024 4.9 13 .16 1.021 5.9 ' 11 .21 1.023 5.2 12 .33 1 1.023 4.9 13 .14 . 1.015 6.0 8 .28 1.011 4.9 7 (Sample too small fc r accurate malysis) 13 28 ` 29 11 31 13 4.2 4.5 6.1 3.7 4.4 3.7 , Avcragef................ Max. var..............| .196 +68% -29% 4.4J +38% -16% ' Subject C (spray painter) 1 i* .08 1.013 6.3 12 47 3.8 .1 2 .05 1.015 5.5 11 57 2.9 ' 1 3. (Sample spoiled) 4* .065 1.010 5.3 11 45 2.9 5 .08 1.015 5.0 . 13 69 5.5 )j 6 ;i2 1.016 5.1 9 42 5.0 rl 7* .035 1.010 5.8 10 53 4.5 *r 8 .12 1.017 5.1 ' 12 61 6.1 k tveragef................ .082 4 At '+*T. var.............. | -1-47% +49% -39% -29%' ire ------------------------------------------------------------------------------------------------------------ 1---------------------- v- __ ' "i'bcsc are overnight samples and represent excretion from 4:00 or 5:00 p.ru. until " "r 8:00 a.m. ' Average concentration calculated as if only one large sample had been collected 0 "T entire period. ioo Average excretion per hour calculated as if only one large sample had been collected h >;1 ' [ :uire period. DUP050312924 % 466 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [uol. SI, no. S TJRIKE SAMPLE 170. .. . TABLE 2 Ur in a r y Le a r Ex c r e t io n LEAD s p. on. pH xi-moosx . traiNB LSAD Subject P (no exposure) mgjl. mg,fee. cc./hr. t/hr. I* - .03 1.022 5.3 9 42 1.3 2 .03 1.020 5.0 . 11 37 1.1 3 .03 1.020 4.9 11 34 1.0 4* .025 1.020 5.0 16 33 1.0 5 ' .045 1.020 4.5 12 40 1.8 6 .035 1.026 5.2 11 31 1.1 Averagef................ Max. var.............. ^ .030 +50% -17% Subject P (with increased water intake) 1.18J +52% -15%- 7* 8 9 .10 11* .12 . 13 14 .025 .055 .04 .045 .035 .04 .045 .025 1.007 1.001 1.010 1.008 1.020 1.023 1.021 1.005 . 5.4 5.1 5.5 4.9 5.0 5.5. 6.3 5.8 8 69 4 105 12 51 11 70 11 44 n 46 11 65 4 117 1.5 5.8 2.0 3.1 1.5 1.8 2.5 2.9 Average!................ Max. var.......... .. .035 +57% -29% 1.98J +193% -24% Omitting No. 8. +29% -29% +56% -24% Subject E (no exposure) 1 .035 1.023 5.1 15 28 1.0 2 .02 1.028 4.8 15 31 .6 3* .025 1.025 6.0 12 39 1.0 4 .03 1.032 4.9 14 20 .6 5* .045 1.020 6.1 14 42 1.9 6 .04 .1.020 . 5.5 13 44 1.8 7 .035 1.025 5.0 13 28 1.0 8* .03 1.020 6.4 12 43 1.8 Average!................ Max. var...............| .033 +37% -40% 1.5| +52% -52% * These are overnight samples and represent excretion from 4:00 or 5:00 p.m. until Y:00 or 8:00 a.m. f Average concentration calculated as if only one large sample had been collected over entire period. t Average excretion per hour calculated aa if only one large sample had been collected over entire period. "T" "ai-w ? DUP050312925 & Not'. 10301 LEAD IN URINE 467 tion per hour might be fairly constant throughout the day. Table 1 shows the result of this calculation. It is to be noted that iii Subjects A and B the gammas of lead per hour are much more nearly constant than the milligrams of lead per liter. In Sub ject C the maximum variation is nearly the same for both the per hour excre tion and the lead concentration. However, in Subject C the actual total per day excretion increased consider ably throughout the test and the per hour excretion values show this much better and more accurately than the concentration values. Subjects D and E are laboratory workers with no abnormal lead ex posure. Subject D was tested under normal living conditions for 2 days and it is shown that about the same variation exists in both the per hour excretion and the concentration. The values, however, fall into a sufficiently narrow range as to be useful- as a measurement. Subject D then in creased his water intake considerably for 2 days with the result shown. It is interesting to note that in the one sample that had a specific gravity of nearly 1.000, the per hour excretion was increased to about three times its previous value and that the general level of excretion was increased some what during this time of increased water intake. The excretion on the following day returned to normal after the subject returned to normal water intake. This experiment indicates that the per hour excretion should not be taken as an average condition when the specific gravity is extremely low. Subject E is another laboratory worker with no abnormal lead expo sure. The lead concentration in this case shows a little smaller variation than the per hour excretion, but still the per hour values fall info a suffi ciently narrow range to be useful as a measurement. On the basis of these data the col lection of 24 hour samples was dis continued and specimens representing 2 or 3 hour excretion are now used as a control on exposure. The general nature of the results obtained indicate that the method is satisfactory. On several occasions specimens from one person have been collected on differ ent days and the values of lead excre tion per hour have checked quite closely. Dis c u s s io n It appears from these experiments that a determination of the lead ex creted per hour, as found by analyzing a specimen representing 2 or 3 hours' excretion during the working day, gives a fairly reliable measure of the average excretion for that day. It must be borne in mind that 24 or 48 hour specimens from the same person show quite a wide range of lead con centration and of lead excreted per day and shorter time samples would also, be expected to vary. The values of the per hour excretion, as indicated in the experiments described in this re port, fall into a sufficiently narrow range to be used as a measurement of the total lead excreted per day which in turn is a measure of lead exposure. No Widely erratic values were ob served provided urine specimens of extremely low specific gravity were not used. This work indicates the possible use of analysis of .instantane ous samples of urine in the control of I i r j \ I i l i I DUP050312926 4- 468 JOURNAL OP INDUSTRIAL HYGIENE AND TOXICOLOGY' [vol. 21, ru. s lead exposure and thereby offers a mens. Extreme care must be taken . procedure that eliminates the difficul- to avoid contamination of these small ties of obtaining 24 or 48 hour speci- specimens. BIBLIOGRAPHY 1. Ke h o e , R. A., Th a man n , F., a n d Cbl Ol a k , J.: Lead absorption-and excretion in relation to diagnosis of load poisoning. True J., IB, 320 (1933) 2. Wil k in s , E.- S., Wil l o u g h b y , C. E., Kk a e mb r , E. O., a n d SmrfH, F. L.: Determination of minute amounts of lead in biological material. Ind. A Eng. Chem'., 7, 33 (1935) 3. Wil l o u g h b y , C. E., Wil k in s , E. S., a s h Ks a e meb , E. O.: Determination of load. Ibid., 7, 285 (1635) .1 DUP050312927