Analysis of environmental fluoride of the coal-burning endemic fluorosis areas in Chongqing

Abstract

Objective To find out the distribution pattern of environmental fluoride in the coal-burning endemic fluorosis areas to provide scientific evidence for establishing prevention and remedial measures in Chongqing. Methods According to historical data in Chongqing In 2008, 4 endemic villages(Lingyun and Lizi Villages of Wushan County, and Taiping and Daqing Villages of Pengshui County) and 2 non-endemic villages (ShuangLou and XianLong Villages of Yongchuan County) were investigated. Dental fluorosis of children in 8 to 12 year old and residents over 16 years of age for clinical skeletal fluorosis were examined in four endemic villages. Five households from each of 6 villages were taken, where 500 g of coal, mixed clay with coal, mixed coal of soil, coal cinder, soil were sampled; 15 people were taken in each village, each household gathering 500 g of corn, rice, potatoes, vegetables, grain and vegetable, 100 g of dried pepper and 250 ml of drinking water were sampled from 15 families of each village. Household drinking water samples were collected 1, each 250 ml. For those having tea-drinking habit, each household was collected 50 g of tea and 600 ml of drinking tea, the amount of fluoride were determined. Indoor and outdoor air was collected and measured in 5 households in each village. Results The detected rate of dental fluorosis of children in endemic areas was 74.65% (736/986). The detected rate of skeletal fluorosis of adult was 7.20%(736/986). The average fluoride content of coal, mixed clay with coal, mixed coal of soil, cinder coal, soil in the endemic villages was (310.56±209.46), (360.51±224.96), (293.62±65.15), (186.59±133.66), (497.54±294.70)mg/kg. The average fluoride content in non-endemic villages was (48.68±10.62), (275.66±62.69), (152.20±34.43), (209.14±188.66),269.98±58.21)mg/kg. The fluoride content level of endemic villages was significantly higher than that of non-endemic villages(t=7.67,31.54,5.82, 5.82, all P 0.05]. The amount of drinking tea in the endemic village[(1.45±0.68)L/d] was higher than that in non-endemic village[(1.00±0.47)L/d, t=4.27, P 0.05)]. Conclusions The fluoride source of coal-burning endemic fluorosis areas are coal and mixed coal of soil in Chongqing. Fluoride enters into human bodies mainly via respiratory, not from food. Although fluoride is rich in pepper, people don't eat it, so reducing the fluoride content in indoor air is the principle measure. Drinking tea may be was one factor of endemic fluorosis, which needs to be further studied. Key words: Coal; Fluoride poisoning; Data collection