Investigation and Analysis on Current Situation of Coal-Burning Fluorosis Prevalence

Objective: The purpose of the paper is to provide the result from investigation on the current situation of coal-burning fluorosis prevalence in Chongqing City and make an assessment on the prevention and curing measures. Method: The Dean’s Method is applied to investigate on the fluorotic teeth of locally-born children aged between 8 to 12;investigate how modified cooking stoves are utilized by households and how food maize and hot pepper are being dried;and test the urinary fluorine content and pepper fluorine content. Result: The investigations show that, in the 661 villages with illness history from the 100 townships of 13 districts in Chongqing City, 11.28% (7464/ 66,162) of the children aged between 8 and 12 suffer from dental fluorosis;the stoves modified rate, qualified rate of modified stoves, and correct utilization rate of qualified modified stoves are respectively 100%, 98.82%, and 99.45%;and food maize and hot pepper’s drying rates are respectively 99.88% and 99.75%. Conclusion: The result shows that the coal-burning type fluorosis prevalence in the endemic area of Chongqing City has decreased dramatically, the preventive measure is effectively implemented, and a long-term preventive mechanism has preliminarily been established.

Analysis the Results of Control and Elimination of Coal-Burning-Borne Endemic Fluorosis in Chongqing City

Objective: Discuss the analysis of the results of control and elimination of coal-burning fluorosis in Chongqing, and evaluate the effect of prevention and control. Methods: Dean’s method was used to investigate the fluorosis for the local children whose ages ranged from 8 to 12 years old, the use of improved stoves in residential households, the drying of corn and pepper for human consumption, and the results were evaluated and discussed according to the national standard for the control and elimination of coal-burning fluorosis. Results: The prevalence rate of dental fluorosis borne-disease in children whose ages ranged from 8 to 12 years old was about 11.28% in 661 historically diseased villages in 100 townships and in 13 districts and counties of Chongqing city. The correct utilization rates of improved stoves, qualified improved stoves, and qualified stoves were 100%, 98.82%, and 99.45%, respectively. The correct drying rates of corn and pepper for human consumption were 99.88% and 99.75% respectively. There are 24 uncontrolled villages, 225 controlled villages, and 412 villages in eliminated disease zones in administrative villages. There are 4 villages and counties in uncontrolled, 4 in controlled, and 5 eliminated areas in districts and counties. Conclusion: Fluorosis borne-disease caused by coal-burning in Chongqing has reached the control and elimination targets of the twelfth Five-year plan.

Distribution of rare earth elements in PM10 emitted from burning coals and soil-mixed coal briquettes

Emission from burning coals is one of the major sources of the airborne particles in China.We carried out a study on the rare earth elements(REEs)in the inhalable particulate matter(PM10)emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system.Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes.The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquetteburning PM10.In addition,the contents of the light rare earth elements(LREEs)are higher than those of the heavy rare earth elements(HREEs)in the PM10 emitted from burning the coals and briquettes,demonstrating that the REEs in both the coal-burning and briquetteburning PM10 are dominated by LREEs.The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals.A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes,being lower than 2,are lower than those in the particles from gasoline-powered vehicle emission.