Investigation Into Environmental Selenium and Arsenic Levels and Arseniasis Prevalence in an Arsenic-Affected Coal-Burning Area.

This study aims to explore whether selenium (Se) concentration correlates with arseniasis in a high-arsenic coal area in the southern Shaanxi Province, China. Herein, an epidemiological investigation was conducted among 100 arsenic (As)-poisoned patients in Ziyang County, an area with high soil As and Se levels. Fifty healthy subjects were selected from areas without endemic As poisoning. The subjects in the high-As coal area were diagnosed with either normal, suspicious, mild, moderate, or severe As poisoning. Local coal, water, soil, corn, and pepper samples, as well as hair, blood, and urine samples of subjects and patients were collected and analyzed for their As and Se contents. The contents of As and Se in coal, soil, corn, pepper, and hair samples from Ziyang County were significantly higher than those in the control area. The As content of hair in Ziyang County positively correlated with As poisoning, whereas the Se content of hair and urine negatively correlated with As poisoning. The Se content in the body was negatively correlated with the degree of As poisoning, indicating that Se may accelerate the metabolism and decumulation of As and antagonize As toxicity.

[Contrast analysis on two air fluorine content measurement methods].

OBJECTIVE: To take the two kinds of sampling and measurement methods of air fluorine content in the endemic fluorosis area to carry on the comparison, understanding their difference and inside relation. METHODS: Sampled 22 households random on the scene in the disease area with two samplers by two methods, at the position of which, at the same time, equidistance, same highness, as close as possible, but not produce interactive effect, to collect 34 of the air sample, and then gained the results by their respective methods of laboratory analysis and statistical analysis. RESULTS: The test of significance between two methods was P > 0.05, the coefficient of correlation was r = 0.7752, the test of significance was P < 0.01, the equation of linear regression between the GB method (X) and the manual method (Y) was Y = 1.1623X + 0.0008, the test of significance of coefficient of regression was P < 0.01. CONCLUSION: Two kinds of methods had no significant differences. They preset the medium degree positive correlation and a linear regression. The air fluoride in different granularity of suspended particles was not the same. The GB method was more applicable to research of synthesis damage towards the exposing crowd in burning coal fluorine, and manual method was more applicable to research of the damage resulting from the exposing crowd in burning coal fluorine through the breath system. Generally speaking, the results of the manual method was higher than the GB method.

[Pilot experiment of fluorine fixing ratio of coated lump stone coal fuel].

The pilot experiment on coated lump stone coal fuel selected from 16 families in Haoping Shanxi were studied. 8 families burned coating high fluorine lump stone coal with lime, clay and low fluorine anthracite, 8 families burned untreated lump stone coal. The results show that the fluorine-fixing ratio at treated group was 75.0% when coal fluorine compared with coal cinder fluorine. In comparison with untreated group, the concentration of door air fluoride lowered 85.7%, SO2 lowered 75.0%, dust lowered 55.3%.

[Regularity of flourine release from fluorine-rich coal combustion in the fluorine poisoning area].

Laboratory experiments and in situ measurements inside farmer's houses indicate that the fluorine concentration of indoor air was positively related with the fluorine content in the consumed coal (R = 0.612, P<0.01), but fluorine content in the coal had no effect on the release rate of coal fluorine under the usual combustion temperature of about 1000 degrees C. The release rate of coal fluorine varied versus combustion temperature ranging from 200 to 1200 degrees C, following a "S" curve pattern, increasing slowly under 300 to 700 degrees C, but quickly under 700 to 1000 degrees C, and then slowly again before finally reaching 100% under 1100 to 1200 degrees C, this curve can be fit by Logistic equation. The release rate of coal fluorine usually depends upon the existence status of fluorine and the chemical and mineral components of the coal. The fluorine in soft coal or anthracite from Guizhou is released more quickly than in bone coal from Southern Shanxi, with the former almost completely released under 1100 degrees C but the later almost completely released under 1200 degrees C. The combustion temperature of civil stoves is at most 1000 degrees C, under which averagely 86.9% of the fluorine in coal from Guizhou and 80.6% of that in bone coal from Southern Shanxi is released.