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Physiological effects of exposure to low concentrations of carbon monoxide
704
U.S.
BUREAU OF MINES NOTES.
[J. F. I.
P H Y S I O L O G I C A L E F F E C T S O F 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 S OF C A R B O N M O N O X I D E . By R. R. Sayers, F. V. Meriwether and W. P. Yant.
THE effect of comparatively low concentration of carbon monoxide for short periods and under normal air conditions of temperature and humidity, with the subject at rest, was studied by Dr. Yandell Henderson and his co-workers. In making recommendations to the New York and New Jersey tunnel commissions he advised that, if the New York-New Jersey vehicular tunnel be so ventilated that persons passing through the tunnel would be exposed to not more than 4 parts of carbon monoxide in IO,OOO parts of air for not longer than 45 minutes, they would experience no ill effects. Supplementary experiments, carried out by us in connection with our studies at the Bureau of Mines experiment station at Pittsburgh, substantiated this advice. In continuing our studies on low concentrations of carbon monoxide, we made a few experiments in a specially constructed gas chamber where the conditions could be accurately controlled. The factors investigated were : ( I ) The effect of long exposure in low concentrations of carbon monoxide; (2) The effect of strenuous exercise; (3) The effect of high temperature and humidity in low concentrations of carbon monoxide. The " work " was done on a bicycle ergometer and calculated as foot pounds. The carbon monoxide was made by dropping formic acid into hot concentrated sulphuric acid and purified by passing through a soda-lime canister. The composition of the gas used was 99.o per cent. and I per cent. air. Analyses were made of blood samples taken from .time to time, and record was kept of the body temperature, pulse, and general condition of the subject. Results of the tests are summarized below : W i t h the s u b j e c t at r e s t :
I
The exposure for 6 hours to 2 parts of CO in i o , o o o caused : (a) saturation of 16 to 2o per cent. of the hemoglobin of the blood with CO ; (b) very mild subjective symptoms of CO poisoning at the end of the test; (c) no noticeable effects after the test.
May, I922.]
U.S.
BUREAU OF MINES NOTES.
705
2
T h e exposure to 3 parts of CO caused: saturation of 22 to 24 per cent. of the hemoglobin with CO a f t e r 4 hours, and 26 to 27 per cent. a f t e r 5 hours ; (b) symptoms at the end of 2 hours absent; a f t e r 4 hours, mild effects attributed to CO poisoning; and a f t e r 5 hours, moderate effects; (c) after-effects of 4 hours' exposure mild; of 5 hours' exposure, moderate. The exposure to 4 parts of CO in IO,OOO caused : 3 (a) saturation of 15 to 19 per cent. of the hemoglobin with CO at the end of I hour, and 21 to 28 per cent. at the end of 2 h o u r s ; (b) after-effects, moderate to marked.
(a)
With the sub/ect e.rercisi~l 9 strenuously: I
T h e exposure for I hour to 2 ~ parts of CO in Io,ooo caused : (a) saturation of I4 to I6 per cent. of the hemoglobin with CO ; (b) moderate symptoms of CO poisoning at the end of the test ; (c) after-effects mild to moderate.
2
T h e exposure for I hour to 4 parts of CO in I o , o o o caused : ( a ) saturation of 23 per cent. of the hemoglobin with CO ; (b) moderate symptoms of CO poisoning; (c) moderate after-effects. F u r t h e r details are given in a recent report issued by the Bureau. Synthetic I n d i g o . m A new synthesis of indigo is described by G. C. BAInEV and R. S. POTTER (Jour. Am. Chem. Soc., 1922, xliv, 2~5-216 ). They used fumaric acid, prepared from maleic acid, as their raw material. Fumaric acid was converted into symmetrical dibromsuccinic acid by treatment with bromine and glacial acetic acid, under pressure at a temperature of Ioo ° C. for 7 hours. The dibromsuccinic acid was converted into symmetrical dianilidosuccinic acid by treatment with aniline. Three hundred grams of an equimolecular mixture of sodium hydroxide and potassium hydroxide were dehydrated by heating at a temperature of 45 °o C. for two and one-half hours in a closed agitated iron pot. Then 3 ° grams of sodamide were added, and a current of anhydrous ammonia was
U.S.
BUREAU OF MINES NOTES.
[J. F. I.
P H Y S I O L O G I C A L E F F E C T S O F 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 S OF C A R B O N M O N O X I D E . By R. R. Sayers, F. V. Meriwether and W. P. Yant.
THE effect of comparatively low concentration of carbon monoxide for short periods and under normal air conditions of temperature and humidity, with the subject at rest, was studied by Dr. Yandell Henderson and his co-workers. In making recommendations to the New York and New Jersey tunnel commissions he advised that, if the New York-New Jersey vehicular tunnel be so ventilated that persons passing through the tunnel would be exposed to not more than 4 parts of carbon monoxide in IO,OOO parts of air for not longer than 45 minutes, they would experience no ill effects. Supplementary experiments, carried out by us in connection with our studies at the Bureau of Mines experiment station at Pittsburgh, substantiated this advice. In continuing our studies on low concentrations of carbon monoxide, we made a few experiments in a specially constructed gas chamber where the conditions could be accurately controlled. The factors investigated were : ( I ) The effect of long exposure in low concentrations of carbon monoxide; (2) The effect of strenuous exercise; (3) The effect of high temperature and humidity in low concentrations of carbon monoxide. The " work " was done on a bicycle ergometer and calculated as foot pounds. The carbon monoxide was made by dropping formic acid into hot concentrated sulphuric acid and purified by passing through a soda-lime canister. The composition of the gas used was 99.o per cent. and I per cent. air. Analyses were made of blood samples taken from .time to time, and record was kept of the body temperature, pulse, and general condition of the subject. Results of the tests are summarized below : W i t h the s u b j e c t at r e s t :
I
The exposure for 6 hours to 2 parts of CO in i o , o o o caused : (a) saturation of 16 to 2o per cent. of the hemoglobin of the blood with CO ; (b) very mild subjective symptoms of CO poisoning at the end of the test; (c) no noticeable effects after the test.
May, I922.]
U.S.
BUREAU OF MINES NOTES.
705
2
T h e exposure to 3 parts of CO caused: saturation of 22 to 24 per cent. of the hemoglobin with CO a f t e r 4 hours, and 26 to 27 per cent. a f t e r 5 hours ; (b) symptoms at the end of 2 hours absent; a f t e r 4 hours, mild effects attributed to CO poisoning; and a f t e r 5 hours, moderate effects; (c) after-effects of 4 hours' exposure mild; of 5 hours' exposure, moderate. The exposure to 4 parts of CO in IO,OOO caused : 3 (a) saturation of 15 to 19 per cent. of the hemoglobin with CO at the end of I hour, and 21 to 28 per cent. at the end of 2 h o u r s ; (b) after-effects, moderate to marked.
(a)
With the sub/ect e.rercisi~l 9 strenuously: I
T h e exposure for I hour to 2 ~ parts of CO in Io,ooo caused : (a) saturation of I4 to I6 per cent. of the hemoglobin with CO ; (b) moderate symptoms of CO poisoning at the end of the test ; (c) after-effects mild to moderate.
2
T h e exposure for I hour to 4 parts of CO in I o , o o o caused : ( a ) saturation of 23 per cent. of the hemoglobin with CO ; (b) moderate symptoms of CO poisoning; (c) moderate after-effects. F u r t h e r details are given in a recent report issued by the Bureau. Synthetic I n d i g o . m A new synthesis of indigo is described by G. C. BAInEV and R. S. POTTER (Jour. Am. Chem. Soc., 1922, xliv, 2~5-216 ). They used fumaric acid, prepared from maleic acid, as their raw material. Fumaric acid was converted into symmetrical dibromsuccinic acid by treatment with bromine and glacial acetic acid, under pressure at a temperature of Ioo ° C. for 7 hours. The dibromsuccinic acid was converted into symmetrical dianilidosuccinic acid by treatment with aniline. Three hundred grams of an equimolecular mixture of sodium hydroxide and potassium hydroxide were dehydrated by heating at a temperature of 45 °o C. for two and one-half hours in a closed agitated iron pot. Then 3 ° grams of sodamide were added, and a current of anhydrous ammonia was