A review of the literature indicated an association among high nitrate ingestion, methemoglobinemia, and pathologic changes in bronchi and lung parenchyma. The present study examined a possible correlation among drinking water nitrate concentration, methemoglobin levels, cytochrome b(5) reductase activity, and acute respiratory tract infection with a history of recurrence (RRTI). Our study was conducted in five village units in the state of Rajasthan, India, with nitrate concentrations of 26, 45, 95, 222, and 459 mg NO(3) ion/L. We randomly selected 88 children. The children were up to 8 years of age, age matched, and represented 10% of the total population of these areas. We obtained detailed RRTI histories and conducted medical examinations. Methemoglobin levels and cytochrome b(5) reductase activity were estimated biochemically. The data collected were statistically analyzed using spreadsheet software on a personal computer. We observed strong interdependence between methemoglobin levels and RRTI in children up to 8 years of age. Methemoglobin levels alone explained 80% of the variation in the RRTI cases. This study indicates that methemoglobinemia, secondary to high nitrate ingestion in drinking water, causes RRTI. Increased production of methemoglobin and free radicals of nitric oxide and oxygen due to nitrate metabolism in the body lead to alveolar damage and mismatching of ventilation and perfusion, which may be the reason for high mortality in children due to RRTI.ImagesFigure 1

No abstract

Large populations consume fluoride-contaminated water, especially in developing countries. The toxic effects of fluorosis take three forms: clinical, skeletal and dental. Research thus far indicates that the manifestations of fluorosis are irreversible. However, it has been observed that the ingestion of calcium, vitamin C or vitamin D, individually, is effective in protection from fluoride toxicity to a certain extent. Therefore, a double blind control trial was conducted to examine the effect of a combination of calcium, vitamin D, and ascorbic acid supplementation in fluorosis-affected children. In the present study, 25 children were selected from an area consuming water containing 4.5 p.p.m. of fluoride, All the children were in the age group 6-12 years and weighed 18-30 kg. They were graded for clinical, radiological and dental fluorosis and relevant biochemical parameters. Grade I skeletal fluorosis and all grades of the manifestation of dental and clinical fluorosis were observed. The children were given ascorbic acid, calcium and vitamin D, well below the toxic dosages in a double blind manner using lactose as a placebo. Follow up revealed a significant improvement in dental, clinical and skeletal fluorosis and relevant biochemical parameters in these children. Thus, the study indicated that fluorosis can be reversed, at least in children, by a therapeutic regimen that is fairly cheap, simple and easily available and without any side effects.

Given that there was documented evidence of an association between diarrhea and high nitrate ingestion, the authors examined drinking water nitrate concentration and its possible correlation(s) with methemoglobin levels, cytochrome b5 reductase activity, and recurrent diarrhea. In addition, the authors studied histopathological changes in the intestines of rabbits in an animal model. Five village areas were studied, and nitrate concentrations (expressed in mg of nitrate per liter of water) of 26, 45, 95, 220, and 459 existed in the respective villages. The study included 88 randomly selected children who were 8 yr of age or younger; they represented 10% of the total population of each of the areas. Detailed histories of recurrent diarrhea were noted, and medical examinations were conducted. Cytochrome b5 reductase activity and methemoglobin levels were estimated biochemically. Collected data were analyzed statistically with Microsoft Excel software. In addition, the authors exposed rabbits to various levels of nitrate, and histopathological changes of the stomach and intestine (small and large) were evaluated. There was a strong relationship between nitrate concentration and recurrent diarrhea; 80% of the recurrent diarrhea cases were explained by nitrate concentration alone. In the rabbit intestines, lymphocytic infiltration and hyperplasia characterized the submucosa as nitrate concentrations increased.