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Effects of reducing fluoride content of indoor air by the Mushan improve coal range, and the heated bed designed and made by these authors are quantitatively evaluated in this paper. The result shows that only heated bed can be effective to prevent fluorosis caused by burning coal containing fluoride.
Typical samples of coal, the components and contents of coal smoke as well as the concentration of fluoride, SO2, IP, CO in indoor and outdoor air in fluorosis areas of the Three Gorges region were studied with the advanced methods of analysis in the past three years. Problems, such as the fluoride level of other polluted environmental samples, the distribution of different size particles in air, the total amount of inhabitants' fluoride intake and their intake pathways in the above mentioned areas were also studied in detail. A fundamental understanding of the environmental characteristics of these areas has thus been obtained.
This paper reports an investigation of contents of soluble fluoride in the environment and foods in Xiushan and Baojing. On the basis of measuring concentrations of soluble fluoride in drinking water, soil, coal, air, fly ash, maize, chilli, and other kinds of vegetables, it is first to expand the pathway of fluoride migrating from coal into human body is through pollution of air by fluoride contained in fly ash on burning of coal, and then via consumption of polluted maize by air. The significant correlation between both the concentrations of fluoride in maize and in fly ash is proved. It is suggested to select the concentration of fluoride in fly ash or in air as the quality index of indoor air and the control target to prevent fluorosis.
Using the method of metabolic balance, we investigated the fluoride metabolism and its change during calcium-magnesium preparation treatment in 60 cases of endemic fluorosis. We found that in patients with fluorosis the intake of fluoride and the levels of urinary, fecal and serum fluoride were several times higher than those of normal controls (P less than 0.01), that the intestinal fluoride apparent absorption rate was 1.5 times higher than that of normal controls (P less than 0.01) and that at a given dietary level of fluoride, there existed a balance of fluoride metabolism. Fluoride intake was positively correlated with intestinal fluoride apparent absorption rate (r = 0.375, P less than 0.01). The combination of calcium and magnesium preparation with fluoride led to decrease of intestinal fluoride apparent rate (P less than 0.05) and increase of fecal fluoride output (P less than 0.05). It seems reasonable to treat fluorosis with calcium-magnesium preparation.
Based on the investigation and analysis of 97 samples of drinking water from an endemic fluorosis area, and 32 samples from a non-endemic fluorosis area, the author suggested that the Mo, Cu content and the changes of their proportions should be considered an important factor in addition to the content of fluorine. In the area where the fluorine is above 2ppm, the higher the proportion of Mo, Cu and F in drinking water, the less serious the disease is. At the same time, it is found that a change in the proportion of Mo and Cu also influences this disease. The higher the proportion of Mo and Cu, the more diseases will occur.
The LD50 for fluoride was elevated from less than 60 mg F/kg body weight to 172 mg F/kg when magnesium (as MgCl2), equivalent to 3 times that of F, was administered by gavage 30 min after the F dose. A dose of 30 mg F/kg elevated the mean steady state of F in serum nearly 1.5-fold and in femoral bone nearly 2-fold when administered with or without the subsequent Mg dose and observed 24 h after the electrolyte dosages. Also, in 24-hour urine the mean F excretion was highest in the F and FMg groups. The total F excretion (fecal + urinary) was elevated 8- and 10-fold when fluoride was administered with or without magnesium, as compared to control levels. Magnesium administration with fluoride did not significantly modify the above mean values of the group given fluoride alone. This suggests that interference with the absorption of fluoride was not the primary protective function of magnesium against the acute toxicity of fluoride. Additional experiments, conducted to further clarify the toxic mechanism of fluoride and the protective mechanism of magnesium, resulted in the following findings: An intraperitoneal dose of 20 mg F/kg elevated fluoride concentration in serum in 1 h about 20 times compared to the controls. Magnesium injected simultaneously with fluoride did not modify the effect of fluoride alone. No significant changes were found in the concentrations of K, Mg, Na or Ca of the lung, skeletal muscle, kidney or liver after these injections except for some trend of elevation of Ca in the heart. However, after a dose of 30 mg F/kg i.p., the heart Ca/Mg mole ratio was elevated within 1 h from 0.037 to 0.194, while all of these rats died within 1 h after the injections. When magnesium, equivalent to 3 times the amount of fluoride was injected, this mole ratio was only 0.095, and all rats in this group survived over 1 h. These results suggest that the lethality of fluoride may be dominantly mediated by the elevated Ca (Ca/Mg ratio) in the heart muscle and that this is correctable by Mg.
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Radioimmunologic study of thyrotropin and thyroid hormones in the blood of those engaged in fluorine production showed moderate functional changes of the hypophysis-thyroid gland system, not accompanied by clinical manifestations of hypo- or hyperthyreosis and caused by disorders of the regulatory chain and fluorine impact on thyroid hormones' metabolism at the level of target cells. Elevation of calcitonin concentration in workers' blood indicated stimulation of thyroid gland parafollicular cells. Phase states in the hypophysis-thyroid gland system were detected along with the dependence of some hormones' concentration on the duration of workers' contact with fluorine compounds and the stage of fluorosis.
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495 clinical cases and 25 radiographic cases of fluorosis of bone diagnosed six years ago in an endemic area showed satisfactory results after six years' treatment with low-fluorine drinking water. Among these, 140 have been completely cured, 105 have gained marked clinical improvement and 172 have gained moderate improvement; the cure rate being 49.49% and the effective rate, 84.84%. Of the 25 X-ray diagnosed cases, 15 showed marked improvement. Radiographic examination has revealed reappearance of evenly distributed fine bone trabeculae. Two cases of grade III osteosclerosis have turned to grade II; 4 to grade I; 8 cases of grade II have turned to grade I; 1 case of grade I has become normal. The results demonstrate that fluorosis of bone is reversible.
An investigation was carried out into urinary fluoride levels of men working at an Auckland fertiliser works where the average of 45 workers was 2.2mg/1 (range 0.6-7.5) with the 12 men in the Manufacturing Department having an average level of 4.2mg/1 (range 1.5-7.5). Radiographic examinations of the skeletal system of the three subjects with the highest urinary fluoride levels showed no evidence of fluorosis. Early morning spot samples were found to be a reasonable indication of total 24-hour fluoride excretions.
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