Toxic Effects of Sulfur

What are the major toxic effects of sulfuric acid How is exposure to sulfuric acid likely to occur ... 

The skin and eyes are especially sensitive to the toxic effects of sulfur mustard. When applied to human skin, about 80% of the dose evaporates and 20% is absorbed (Vogt et al., 1984). About 12% of the amount absorbed remains at the site and the remainder is distributed systemically (Renshaw, 1946). Doses up to 50 pg/ cm cause erythema, edema, and sometimes small vesicles. Doses of 50-150 pg/cm cause bullous-type vesicles, and larger doses cause necrosis and ulceration with peripheral vesication. Droplets of liquid sulfur mustard containing as little as 0.0025 mg may cause erythema (Ward et al., 1966). Eczematous sensitization reactions were reported in several early studies and may occur at concentrations below those causing direct primary irritation (Rosenblatt et al., 1975). In humans, the LCtso (estimated concentration x exposure period lethal to 50% of exposed individuals) for skin exposures is 10,000 mg-min/m (DA, 1974) (for masked personnel however, the amount of body surface area exposed was not reported). The ICt 50 (estimated concentration x exposure period incapacitating to 50% of exposed individuals) for skin exposures is 2000 mg-min/m at 70-80°F in a humid enviromnent and 1000 mg-min/m at 90°F in a dry enviromnent (DA, 1974, 1992). The ICtso for contact with the eyes is 200 mg-min/m (DA, 1974, 1992). The LDl for skin exposure is 64 mg/kg and the LD50 is estimated to be about 100 mg/kg (DA, 1974,1992). 

The mechanism of action of sulfur mustard is multifaceted and complex, and has been reviewed in some detail by Papirmeister et al. (1991), Hurst and Smith (2008), and Smith et al. (2008). Efforts to understand the mechanisms of sulfur mustard toxicity are ongoing. Basically, sulfur mustard disrupts the interface of the epidermis and basement membrane causing blistering between the epidermis and dermis. Both immediate (immediate cell membrane damage) and delayed phases (secondary effects resulting from inflammatory responses, DNA damage, vascular leakage) have been described for sulfur mustard-induced dermal effects (Somani and Babu, 1989). Many of the toxic effects of sulfur mustard can be attributed to oxidative stress. 

The toxic effects of sulfur mustard in humans and animals have been extensively reviewed by ATSDR (2003), Sidell and Hurst (1992), Somani (1992), Watson and Griffin (1992), lOM (1993), NRC (2003), and Romano et al. (2008). 

Balali-Mood, M., Hefazi, M. (2006). Comparison of early and late toxic effects of sulfur mustard in Iranian veterans. Basic Clin. Pharmacol. Toxicol. 99 273-82. 

Toxic effects of sulfur mustard and ethyleneimine on animals were described in the 19th century. The powerful vesicant action of sulfur mustard led to its u.se in World War I. and medical examination of the victims revealed that tissues were damaged at sites distant from the area of contact." Such systemic elTects included leukopenia, bone marrow aplasia, lymphoid tissue suppression, and ulceration of the gastrointestinal tract. Sulfur mustard was shown to be active against animal tumors, but it was too nonspecific for clinical use. A variety of nitrogen mustards were synthesized between the two world wars. Some of these compounds (e.g.. 

Balali-Mood, M. (1996). Delayed toxic effects of sulfur mustard in 1428 patients. In Proceedings of the Chemical Biological Medical Treatment Symposium An exploration ofpresent capabilities and future requirements (pp. 125—133). Spiez, Switzerland. 

Chevillard, M., Lainee, P., Robineau, P., and Puchelle, E. (1992). Toxic effects of sulfur mustards on respiratory epithelial cells in culture. Cell Biol Toxicol 8, 171-81. 

Balali M. The evaluation of late toxic effects of sulfur mustard poisoning in 1428 Iranian veterans. In Proceedings of Seminar on Late Complications of Chemical Warfare Agents in Iranian Veterans. Tehran, Iran, Veteran Foundation, Tehran Tehran University Press, 1992, pp. 15-37. 

M. and Rabatabaee, A. (2005), Evaluation of delayed toxic effects of sulfur mustard poisoning in... 

Among sulfur-containing compounds, the toxic effects of sulfur dioxide have importance in practice. Sulfur dioxide belongs to the group of major air pollutants, and emissions from industry and ocean-going ships are the main sources of its input into the environment. 

The skin and eyes are especially sensitive to the toxic effects of sulfur mustard. When applied to human skin, about 80% of the dose evaporates and 20% is absorbed (Vogt et al. 1984). Skin penetration is at a rate of about 1 ig cm" min at a temperature of 75 °F (Renshaw 1946). About 12% of the amount absorbed remains at the site and the remainder is distributed systemically (Renshaw 1946). Doses to 50 pg/cm cause erythema, edema, and sometimes small vesicles. Doses of 50-150 pg/cm cause bullous-type vesicles, and larger doses cause necrosis and ulceration with peripheral vesication. Droplets of liquid sul-... 

Second, the toxic effect of sulfur is permanent and cannot be reversed. Toxic sulfides include inorganic and organic sulfur. Inorganic sulfur is mainly hydrogen sulfide, organic sulfur include COS, CS2, RSH, C4H6S (Thiofuran). Previous studies showed that when the sulfide comes into contact with the active component of the catalyst, chemisorptions follows two paths ... 

Bisulfites are oxidised in the body by sulfite oxidase (sulfite ferricytochrom c oxidoreductase) to sulfates, which are excreted in the urine. The enzyme activity is individual, and toxic effects of sulfur dioxide and sulfites are therefore variable. Some individuals tolerate amounts of up to 50 mg/kg, while in sensitive individuals such concentrations will cause headaches, nausea and diarrhoea. In asthmatics receiving steroids, sulfites may cause allergic reactions (ADI = 0.7 mg/kg bodyweight). 

Razavi, S.M., Salamati, P., Saghafinia, M., et al, 2012. A review on delayed toxic effects of sulfur mustard in Iranian veterans. Daru J. Pharm. Sci. 20 (1), 51-59. 

Specific toxic effects of sulfur mustard have also been reported in the CNS and may range from agitation to seizures (Balali-Mood and Navaeian, 1986). 

M. Balali-Mood, H. Kahrom, R. Afshari, D. Attaran, R. Zojaji and M. Kam-rani. Delayed toxic effects of sulfur mustard on upper and lower respiratory tracts in Iranian veterans, Toxicol Lett., 2010,196, S81. 

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