Abstract

The toxicology of hydrogen sulfide (H₂S) and sour gas on the eye has a long history beginning at least with Ramazzini's observations [Ramazzini B. Diseases of Workers—De Morbis Artificum Diatriba—1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc.; 1964. 98–99 pp.]. In contrast, a recent review by Alberta Health and Wellness (AHW Report) concluded that there is little evidence of eye irritation following short-term exposures to H₂S at concentrations up to 100 ppm and that the H₂S literature on the eye is a series of unsubstantiated claims reproduced in review articles dating back to the 1930s [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide: a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In this paper, we evaluated this claim through a historical review of the toxicology of the eye. Ramazzini noted the effects of sewer gas on the eye [Ramazzini B. Diseases of Workers—De Morbis Artificum Diatriba—1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc. 1964. 98–99 pp.]. Lehmann experimentally showed eye effects in men at 70–90 ppm H₂S and also in animals [Lehmann K. Experimentalle Studien uber den Einfluss technisch und hygienisch wichtiger Gase und Dampfe auf den Organismus. Arch Hyg 1892;14:135–189]. In 1923, Sayers, Mitchell and Yant reported eye effects in animals and men at 50 ppm H₂S. Barthelemy showed eye effects in animals and men at 20 ppm H₂S [Barthelemy HL. Ten years' experience with industrial hygiene in connection with the manufacture of viscose rayon. J Ind Hyg Toxicol 1939;21:141–51]. Masure experimentally showed that H₂S is the causative agent of eye impacts in animals and men [Masure R. La Keratoconjunctivite des filatures de viscose; etude clinique and experiementale. Rev Belge Pathol 1950;20:297–341]. Michal upon microscopic examination of the rat's cornea, found nuclear pyknosis, edema and separation of cells in the eye following exposures for 3 h at 36 ppm H₂S [Michal FV. Eye lesions caused by hydrogen sulfide. Cesk Ophthalmol 1950;6;5–8]. In 1975, in Alberta, irreversible eye damage and photophobia were experimentally produced in calves exposed to 20 ppm H₂S for 1 week [Nordstrom GA. A study of calf response of ammonia and hydrogen sulfide gases. Thesis, University of Alberta, Department of Agricultural Engineering, Edmonton Alberta; 1975, 218 pp.]. Alberta Environmental Centre documented clinical irritation of the eye at 40 ppm H₂S in 6 hours in rats [Alberta Environmental Centre. Morphological observations in rats exposed for six hours to an atmosphere of 0, 56, or 420 mg/m³ hydrogen sulfide. AECV86-A1. Alberta Environmental Centre, Vegreville, Alberta; 1986b. 28 pp.]. In two sour gas blow-outs in Alberta, in the early 1980s, eye injury was documented in humans and animals at 0.5 ppm H₂S. Community studies in the United States, Europe and New Zealand suggest that acute exposure to 25 ppb H₂S is the lowest concentration to irritate the eyes; with chronic exposure, serious eye effects are suggested. In contrast to the conclusion, all of the studies, except one, cited in the AHW Report indicate toxic effects on the eye below 100 ppm H₂S [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide (H₂S): a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In addition, the AHW Report (2002) mis-presented two studies as ‘clinical studies’, claiming they reported no evidence of eye effects in humans from 2 and 30 ppm H₂S for 30–40 minutes [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide (H₂S): a technical review, Alberta Health and Wellness, October 2002, 81pp.].

Keywords: Hydrogen sulfide; H₂S; Sour gas; Eye; Conjunctivitis; Historical review; Mechanism

Article Outline

1. Introduction

2. Methods

3. An historical perspective of hydrogen sulfide and the eye

3.1. Lehmann (1892)

3.2. U.S. Bureau of Mines: Sayers et al. (1923), Mitchell and Davenport (1924), Mitchell and Yant (1925), Aves et al. (1929) and Yant (1930)

3.3. Sjorgen (1939)

3.4. Viscose rayon spinning rooms: Kranenburg and Kessener (1925), Lewey (1938), McDonald (1938), Barthelemy (1939), Rubin and Arieff (1945), Masure (1950), Nyman (1954), Nesswetha (1969) and Vanhoorne et al. (1995)

3.5. Occupational, experimental and community exposures: Michal (1950), Ahlborg (1950), Carson (1963), Beasley (1963), US Department of Public Health Service, Terre Haute (1964), Luck and Baye (1989) and Schiffman et al. (2005)

3.6. Chronology of Alberta studies: Nordstrom (1975), Burnett et al. (1977), Lodgepole Blowout Report (1984), Drummond Blow-Out (Alberta Environmental Centre, 1984), Arnold et al. (1985), Alberta Environmental Centre, 1986a and Alberta Environmental Centre, 1986b and Lefebvre et al. (1991)

3.7. South Karelia air pollution studies: Haahtela et al. (1992) and Marttila et al., 1994 and Marttila et al., 1995

3.8. Community study in Rotorua: Bates et al., 1998 and Bates et al., 2002

4. Critique of Alberta Health and Wellness Report (2002) of H₂S

4.1. Comparison of AHW Report (2002) review of H₂S effects on the eye with other major reviews

4.2. Review of the scientific studies to support AHW Report (2002) conclusion that there is “very little evidence of eye irritation following short-term exposures to H₂S at concentrations up to 100 ppm”

4.2.1. Non-clinical studies

4.2.2. Clinical studies

4.2.3. Case-control and observational studies from sour gas releases

4.3. AHW Report (2002) critique of Alberta Health (1988)

5. Conclusion

References