et al., 1995), add credence to the link between colonic sulfide levels and ulcerative colitis. Indeed, drug therapy involving 5-aminosalicylic acid (Pitcher et al., 1995; Roediger and Duncan, 1996) and gentamycin (Pitcher et al., 1994) for ulcerative colitis is known to suppress hydrogen sulfide production. Moreover, standard therapy for ulcerative colitis patients has included restriction of foods, such as milk, eggs, and cheese, that are significant sources of dietary sulfur (Truelove, 1961). More recently, dextran sulfate sodium-induced ulcerative colitis in rats was shown to be exacerbated by dietary iron supplementation, a potent oxidant, but was ameliorated by vitamin E supplementation (Carrier et al., 2002). However, vitamin E supplementation did not affect oxidative stress, as measured by plasma and colonic lipid peroxides and glutathione peroxidase activity, thus suggesting another mechanism for reducing inflammation.

Adverse effects that have been associated with sulfate ingestion include osmotic diarrhea and ulcerative colitis. Generally, a self-regulating effect occurs in that higher concentrations of water sulfate have an odor and off taste, which causes those exposed to water with a high sulfate content to use bottled water. Mineral water sources, however, can vary widely in both cation and anion concentration. Nonetheless, studies have shown that both demineralized bottled water and spring bottled water contain sulfate levels below 500 mg/L, with most lower than 250 mg/L (Allen et al., 1989; Ikem et al., 2002).

Short-term exposure (3 days) to sulfate levels in water (concentration 1,200 mg/L, which would lead to ingestion of 3.6 g of sulfate based on the median intake of water for 19- to 30-year-old men of 3 L/day [Appendix D]), did not induce noticeable diarrhea in the CDC/EPA study in healthy adults (EPA, 1999a). Regression analysis of diarrhea frequency by sulfate dose (dose/kg of body weight) found that sulfate dose was not a significant predictor of diarrhea (EPA, 1999a). Longer-term studies of 6 days in six healthy men showed little change at 2.9 g (1,200 mg/L)/day as well (Heizer et al., 1997). Severe diarrhea has been noted when 6.7 g of sulfate was given in a single dose, but was absent when provided in four divided doses (Cocchetto and Levy, 1981).