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Urinary thiosulphate as an indicator of exposure to hydrogen sulphide vapour
Clinica Chimica Acta, 164 (1987) 7-10 Elsevier
7
CCA 03738
Urinary thiosulphate as an indicator of exposure to hydrogen sulphide vapour J. Kangas a and H. Savolainen b a Regional (Received
Institute of Occupational Health, Kuopio and ’ Institute of Occupational Health, Helsinki (Finland)
14 July 1986; revision received 14 November
Key words: Hydrogen
sulphide;
1986; accepted
Thiosulphate; Bromobimane; Occupational exposure
after revision 20 November
Urinalysis:
Histotoxic
1986)
hypoxia;
Summary Urinary thiosulphate analysed as its bromobimane complex by liquid chromatography revealed quantitatively a preceding hydrogen sulphide gas exposure. The highest thiosulphate concentrations were detected 15 h after the exposure. Controls without a contact to sulphides showed low excretion rates of thiosulphate so that exposures clearly below the fatal hydrogen sulphide gas concentrations could be detected. The urinalysis can therefore be used in the occupational health care as well as for forensic ends.
Introduction Hydrogen sulphide is a potent inhibitor of the terminal cytochrome oxidase of the mitochondrial respiratory chain [l]. The ensuing histotoxic hypoxia is life-threatening at inhaled hydrogen sulphide concentrations above 31 pmol/l(750 ppm, ref. [2]). Hydrogen sulphide vapour is an occupational hazard in oil drilling and refining [3], in tanneries and pelt processing [4], in the rayon fibre production [5], in the chemical pulp and paper industry [6] and in facilities for domestic animals [7]. The high vapour pressure of hydrogen sulphide makes it possible that significant gas concentrations develop rapidly in accidents involving its leakage from the processes. Sudden accidental deaths in these situations may occur although their cause may pose diagnostic problems if the odour of hydrogen sulphide is no longer detectable. Sulphide anion has been detected in poisoning victims by ion-specific
Correspondence
to: Dr. H. Savolainen,
0009-8981/87/$03.50
Institute
of Occupational
0 1987 Elsevier Science Publishers
Health,
B.V. (Biomedical
SF-00290
Division)
Helsinki,
Finland,
8
electrode ]8] or with ion chromatography 191.It is not known whether they can be used in the detection of nonfatal exposure to hydrogen sulphide gas. One of the oxidation products of hydrogen sulphide metabolism is thiosulphate [Z], and in this study, we have demonstrated its excretion in urine after exposure to hydrogen sulphide gas at concentrations found in industry. The test is thus suitable for monitoring in occupational health care as well as in the diagnosis of poisoning cases. Subjects and methods Hydrogen sulphide gas in a pelt processing plant was sampled and analyzed as described before [6]. Expe~ent~ gas exposures were conducted in a 3 m3 closed chamber by diluting pure gas with air to reach concentrations of 330 nmol/l (8 ppm), 740 nmol/l (18 ppm) or 1240 nmol/l (30 ppm). Informed volunteers were exposed to these concentrations for 30-45 min so that the allowed occupational exposure limit of 410 nmol/l (10 ppm) for 8 h was never exceeded. Urinary thiosulphate was analysed as its bromobimane complex by liquid chromatography [lo] in every urine sample voided within 24 h after the exposure. Freshly voided urine samples were frozen and stored at - 2~5~C until analysis. The results were corrected for the excreted creatinine analysed in the same samples [II]. The recovery of added thiosulphate in urine at concentration of 50 ,umol/l was 92% and at 20 ~mol/l it was 80%. The coefficient of variation (CV) was 0.05. Urine samples obtained from m~ntenance men in the pelt processing plant were then analysed for t~osulphate. The visits of the workers in the hydrogen sulphide contaminated process water rooms were timed. The product of the exposure time @in) and the gas concentration in air (nmol/l) was used in the comparison to the thiosulphate excretion. Twenty-nine lumberjacks without any exposure to hydrogen sulphide served as controls for the thiosulphate analysis in their morning urine. The mathematical simulations were made with the least squares method. Results and discussion The controls excreted low amounts of t~osulphate (2.9 k 2.5 ~mol/~ol creatinine, f SD, n = 29) with negligible diurnal variation. The chamber experiments with volunteers showed that the highest urinary thiosulphate concentration was invariably detected I5 h after the exposure, i.e. in the morning urine after the exposure on the preceding day (Fig. 1). After this point, the urinary thiosulphate concentration remained low probably reflecting the fact that most of the absorbed sulphide had already been oxidized within 15 h after the exposure. The urinary thiosulphate concentration changed according to the product of gas concentration and exposure time, Therefore, this product accurately predicted the urinary thiosulphate concentration (Fig. 2) so that the latter can be used as an exposure indicator to hydrogen sulphide gas.
3
U-thiosulphate (~mol/mmol creatinine)
I j/
30 --
y= 2.06x-1.24
20 --
Fig. 1. Increase in the urinary thiosulphate concentration in experiments exposure of an informed volunteer to 740 mnol HzS/l (18 ppm) for 30 min. Samples were taken from each voided urine and analysed for tbiosulphate. The excretion of urinary thiosulphate increases linearly up to 15 h. The sample taken at 17 h is similar to ~uee~tratio~ detected in controls (c, mean of 29 persons, bars indicate 1 SD) or 1 h before the exposure ( - 1). This may indicate that major part of the inhaled hydrogen sulphide was metabolized within 15 h. U-thiosul~hate bmol/mmol
creatinine)
60
H,S
vapour
&mat
x minll)
Fig. 2, Urinary ~os~phate 15 h after the exposure as a function of the product of time and hydrogen sulphide gas concentration in four cases of visit to gas-contaminated waste water treatment room in a pelt processing plant. The products correspond to 620 to 4100 nmol Has/l for lo-60 min when no respiratory protector was used. Hydrogen sulpbide is not absorbed through the skin.
10
The urine in the bladder acts as a reservoir of excreted thiosulphate allowing thus the accumulation of the oxidation product of the inhaled hydrogen sulphide. The metabolic pathway includes at least two oxidation steps [2] explaining the delayed build-up of the thiosulphate product. The much lower thiosulphate excretion later on is a relative handicap of the application of the test although the necessity of the first morning urine sample was quickly understood by the participants of our study. The urinary test may be preferable to the detection of blood sulphide anion as it is noninvasive. The latter may have its place in the elucidation of immediate deaths due to hydrogen sulphide gas with no time lag for the formation of oxidation products. The blood test has not been tried in the low-level hydrogen sulphide exposure while the urinary thiosulphate test should reveal gas concentrations commonly found, e.g. in paper mills [6]. References 1 Nicholls P, Kim J-K. Sulphide as an inhibitor and electron donor for the cytochrome c oxidase system. Can J Biochem 1982;60:613-623. 2 Beauchamp Jr RO, Bus JS, Popp JA, Boreiko CJ, Andjelkovich DA. A critical review of the literature on hydrogen sulphide toxicity. CRC Crit Rev Toxic01 1984;13:25-97. 3 Arnold IMF, Dufresne RM, Alleyne BC, Stuart PJW. Health implication of occupational exposures to hydrogen sulphide. J Occup Med 1985;27:373-376. 4 Audeau FM. Hydrogen sulphide poisoning: associated with pelt processing. NZ Med J 1985;98:145-147. 5 Higashi T, Toyama T, Sakurai H, Nakaza M, Omae K, Nakadate T, Yamaguchi N. Cross-sectional study of respiratory symptoms and pulmonary functions in rayon textile workers with special reference to H,S exposure. Ind Health 1983;21:281-292. 6 Kangas J, Jappinen P, Savolainen H. Exposure to hydrogen sulfide, mercaptans and sulfur dioxide in pulp industry. Am Ind Hyg Assoc J 1984;45:787-790. 7 Donham KJ, Knapp LW, Monson R, Gustafson K. Acute toxic exposure to gases from liquid manure. J Occup Med 1982;24:142-145. 8 McAnalley BH, Lowry WT, Oliver RD, Garriott JC. Determination of inorganic sulfide and cyanide in blood using specific ion electrodes: Application to the investigation of hydrogen sulfide and cyanide poisoning. J Analyt Toxic01 1979;3:111-114. 9 Wang W, Chen Y, Wu M. Complementary analytical methods for cyanide, sulphide, certain transition metals and lanthanides in ion chromatography. Analyst 1984;109:281-286. 10 Newton GL, Dorian R, Fahey RC. Analysis of biological thiols: derivatization with monobromobimane and separation by reversephase high-performance liquid chromatography. Analyt Biochem 1981;114:383-387. 11 Clark Jr LC, Thompson HL. Determination of creatine and creatinine in urine. Analyt Chem 1949;41:1218-1221.
7
CCA 03738
Urinary thiosulphate as an indicator of exposure to hydrogen sulphide vapour J. Kangas a and H. Savolainen b a Regional (Received
Institute of Occupational Health, Kuopio and ’ Institute of Occupational Health, Helsinki (Finland)
14 July 1986; revision received 14 November
Key words: Hydrogen
sulphide;
1986; accepted
Thiosulphate; Bromobimane; Occupational exposure
after revision 20 November
Urinalysis:
Histotoxic
1986)
hypoxia;
Summary Urinary thiosulphate analysed as its bromobimane complex by liquid chromatography revealed quantitatively a preceding hydrogen sulphide gas exposure. The highest thiosulphate concentrations were detected 15 h after the exposure. Controls without a contact to sulphides showed low excretion rates of thiosulphate so that exposures clearly below the fatal hydrogen sulphide gas concentrations could be detected. The urinalysis can therefore be used in the occupational health care as well as for forensic ends.
Introduction Hydrogen sulphide is a potent inhibitor of the terminal cytochrome oxidase of the mitochondrial respiratory chain [l]. The ensuing histotoxic hypoxia is life-threatening at inhaled hydrogen sulphide concentrations above 31 pmol/l(750 ppm, ref. [2]). Hydrogen sulphide vapour is an occupational hazard in oil drilling and refining [3], in tanneries and pelt processing [4], in the rayon fibre production [5], in the chemical pulp and paper industry [6] and in facilities for domestic animals [7]. The high vapour pressure of hydrogen sulphide makes it possible that significant gas concentrations develop rapidly in accidents involving its leakage from the processes. Sudden accidental deaths in these situations may occur although their cause may pose diagnostic problems if the odour of hydrogen sulphide is no longer detectable. Sulphide anion has been detected in poisoning victims by ion-specific
Correspondence
to: Dr. H. Savolainen,
0009-8981/87/$03.50
Institute
of Occupational
0 1987 Elsevier Science Publishers
Health,
B.V. (Biomedical
SF-00290
Division)
Helsinki,
Finland,
8
electrode ]8] or with ion chromatography 191.It is not known whether they can be used in the detection of nonfatal exposure to hydrogen sulphide gas. One of the oxidation products of hydrogen sulphide metabolism is thiosulphate [Z], and in this study, we have demonstrated its excretion in urine after exposure to hydrogen sulphide gas at concentrations found in industry. The test is thus suitable for monitoring in occupational health care as well as in the diagnosis of poisoning cases. Subjects and methods Hydrogen sulphide gas in a pelt processing plant was sampled and analyzed as described before [6]. Expe~ent~ gas exposures were conducted in a 3 m3 closed chamber by diluting pure gas with air to reach concentrations of 330 nmol/l (8 ppm), 740 nmol/l (18 ppm) or 1240 nmol/l (30 ppm). Informed volunteers were exposed to these concentrations for 30-45 min so that the allowed occupational exposure limit of 410 nmol/l (10 ppm) for 8 h was never exceeded. Urinary thiosulphate was analysed as its bromobimane complex by liquid chromatography [lo] in every urine sample voided within 24 h after the exposure. Freshly voided urine samples were frozen and stored at - 2~5~C until analysis. The results were corrected for the excreted creatinine analysed in the same samples [II]. The recovery of added thiosulphate in urine at concentration of 50 ,umol/l was 92% and at 20 ~mol/l it was 80%. The coefficient of variation (CV) was 0.05. Urine samples obtained from m~ntenance men in the pelt processing plant were then analysed for t~osulphate. The visits of the workers in the hydrogen sulphide contaminated process water rooms were timed. The product of the exposure time @in) and the gas concentration in air (nmol/l) was used in the comparison to the thiosulphate excretion. Twenty-nine lumberjacks without any exposure to hydrogen sulphide served as controls for the thiosulphate analysis in their morning urine. The mathematical simulations were made with the least squares method. Results and discussion The controls excreted low amounts of t~osulphate (2.9 k 2.5 ~mol/~ol creatinine, f SD, n = 29) with negligible diurnal variation. The chamber experiments with volunteers showed that the highest urinary thiosulphate concentration was invariably detected I5 h after the exposure, i.e. in the morning urine after the exposure on the preceding day (Fig. 1). After this point, the urinary thiosulphate concentration remained low probably reflecting the fact that most of the absorbed sulphide had already been oxidized within 15 h after the exposure. The urinary thiosulphate concentration changed according to the product of gas concentration and exposure time, Therefore, this product accurately predicted the urinary thiosulphate concentration (Fig. 2) so that the latter can be used as an exposure indicator to hydrogen sulphide gas.
3
U-thiosulphate (~mol/mmol creatinine)
I j/
30 --
y= 2.06x-1.24
20 --
Fig. 1. Increase in the urinary thiosulphate concentration in experiments exposure of an informed volunteer to 740 mnol HzS/l (18 ppm) for 30 min. Samples were taken from each voided urine and analysed for tbiosulphate. The excretion of urinary thiosulphate increases linearly up to 15 h. The sample taken at 17 h is similar to ~uee~tratio~ detected in controls (c, mean of 29 persons, bars indicate 1 SD) or 1 h before the exposure ( - 1). This may indicate that major part of the inhaled hydrogen sulphide was metabolized within 15 h. U-thiosul~hate bmol/mmol
creatinine)
60
H,S
vapour
&mat
x minll)
Fig. 2, Urinary ~os~phate 15 h after the exposure as a function of the product of time and hydrogen sulphide gas concentration in four cases of visit to gas-contaminated waste water treatment room in a pelt processing plant. The products correspond to 620 to 4100 nmol Has/l for lo-60 min when no respiratory protector was used. Hydrogen sulpbide is not absorbed through the skin.
10
The urine in the bladder acts as a reservoir of excreted thiosulphate allowing thus the accumulation of the oxidation product of the inhaled hydrogen sulphide. The metabolic pathway includes at least two oxidation steps [2] explaining the delayed build-up of the thiosulphate product. The much lower thiosulphate excretion later on is a relative handicap of the application of the test although the necessity of the first morning urine sample was quickly understood by the participants of our study. The urinary test may be preferable to the detection of blood sulphide anion as it is noninvasive. The latter may have its place in the elucidation of immediate deaths due to hydrogen sulphide gas with no time lag for the formation of oxidation products. The blood test has not been tried in the low-level hydrogen sulphide exposure while the urinary thiosulphate test should reveal gas concentrations commonly found, e.g. in paper mills [6]. References 1 Nicholls P, Kim J-K. Sulphide as an inhibitor and electron donor for the cytochrome c oxidase system. Can J Biochem 1982;60:613-623. 2 Beauchamp Jr RO, Bus JS, Popp JA, Boreiko CJ, Andjelkovich DA. A critical review of the literature on hydrogen sulphide toxicity. CRC Crit Rev Toxic01 1984;13:25-97. 3 Arnold IMF, Dufresne RM, Alleyne BC, Stuart PJW. Health implication of occupational exposures to hydrogen sulphide. J Occup Med 1985;27:373-376. 4 Audeau FM. Hydrogen sulphide poisoning: associated with pelt processing. NZ Med J 1985;98:145-147. 5 Higashi T, Toyama T, Sakurai H, Nakaza M, Omae K, Nakadate T, Yamaguchi N. Cross-sectional study of respiratory symptoms and pulmonary functions in rayon textile workers with special reference to H,S exposure. Ind Health 1983;21:281-292. 6 Kangas J, Jappinen P, Savolainen H. Exposure to hydrogen sulfide, mercaptans and sulfur dioxide in pulp industry. Am Ind Hyg Assoc J 1984;45:787-790. 7 Donham KJ, Knapp LW, Monson R, Gustafson K. Acute toxic exposure to gases from liquid manure. J Occup Med 1982;24:142-145. 8 McAnalley BH, Lowry WT, Oliver RD, Garriott JC. Determination of inorganic sulfide and cyanide in blood using specific ion electrodes: Application to the investigation of hydrogen sulfide and cyanide poisoning. J Analyt Toxic01 1979;3:111-114. 9 Wang W, Chen Y, Wu M. Complementary analytical methods for cyanide, sulphide, certain transition metals and lanthanides in ion chromatography. Analyst 1984;109:281-286. 10 Newton GL, Dorian R, Fahey RC. Analysis of biological thiols: derivatization with monobromobimane and separation by reversephase high-performance liquid chromatography. Analyt Biochem 1981;114:383-387. 11 Clark Jr LC, Thompson HL. Determination of creatine and creatinine in urine. Analyt Chem 1949;41:1218-1221.