| Fluoride is a halogen gas element with double threshold effect on human body.The intake of appropriate amount of fluoride helps to protect teeth and prevent bone diseases.Excessive intake of fluoride will cause dental plaque and skeletal fluorosis.Fluorine geochemical anomaly is considered one of the leading causes of fluoride exposure in body,but in our country southwest coal type fluorine exposure area "source" of fluoride exposure on human body and its exposure route is still controversial,especially coal and water fluoride content of endemic fluorosis produced in the lower area phenomenon the reason and mechanism of it is not clear,low background area fluorine health risk has become one of the focus of medical geology.This project selects Qianxi County,a coal-fired fluorosis epidemic area in Guizhou Province,as the research area.And systematically collected water 35 pieces,soil 79 pieces,coal 71 cases,food 173 cases,human hair 329 cases and nails 287 cases in different geological background areas of coal measures strata area(Village A),bare carbonate area(Village B)and Quaternary red clay buried hills(Village C)and conducted epidemiological investigations.The Major conclusions are as follows.(1)Different regional geological environmental backgrounds restrict the distribution characteristics of fluorine content in environmental media(drinking water,soil,coal and food)in each region.The mean values of water fluoride in coal measure strata,carbonate exposed areas and quaternary red clay buried hilly areas were 0.12mg/L,0.08mg/L and 0.19mg/L,respectively.The total surface soil fluoride(Ft)and soluble fluoride(Fw)in coal measure strata were 564.84?911.04 mg/kg and 0.9?4.62 mg/kg,respectively;the Ft and Fw in exposed carbonate rocks were 798.82?829.13 mg/kg and 1.08?0.22 mg/kg,respectively;and the Ft and Fw in quaternary red clay buried hills were 1608.12?2113.42 mg/kg and 4.89?9.92 mg/kg,respectively.The average total fluorine content in the coal measure strata,carbonate exposed areas and quaternary red clay buried hilly areas was 920.32 mg /kg,1621.22 mg /kg and 2720.90 mg /kg,reaching the pollution level.The fluorine content of coal in each region is much lower than that of soil.The mean values of fluorine in coal measure strata,exposed carbonate rocks and quaternary red clay buried hilly regions are 207.13 mg /kg,245.28 mg /kg and 131.74 mg /kg,respectively.In addition,the fluorine content of coal baked pepper is relatively high in coal measure strata,carbonate exposed areas and quaternary red clay buried hilly areas,with the mean values of 371.60 mg/kg,177.32 mg/kg and 67.36 mg/kg respectively.Therefore,the environmental medium with high fluorine content is the fluorine source for fluorine migration and transformation in the coal-burning endemic fluorosis areas.(2)There were significant differences in the distribution of drinking water fluorine,total surface soil fluorine(Ft)and water-soluble fluorine(Fw)in different geological background areas(P<0.05).There was a significant difference in total fluorine between coal measure stratigraphic area and red clay hilly area(P<0.05).There was significant difference in total fluorine content between coal measure strata and carbonate bare areas and red clay hilly areas(P<0.05).The fluorine content of Chinese cabbage in the exposed area of carbonate rock was significantly different from that in the coal measure stratigraphic area and red clay hilly area(P<0.05).There was significant difference in fluorine content between the coal measure stratigraphic area and the red clay hilly area(P<0.05).There was significant regional difference in fluorine content of coal baked pepper in each region(P<0.05).(3)The fluoride exposure level in the three areas was high,and the mean value of fluoride in hair and nails was far higher than that in the control area,and the fluorine content in hair was significantly higher than that in nails(P<0.05).Combined with the regional background differences,it was found that there were regional differences in the distribution of fluoride content in hair and nails in each region.After the subjects were grouped by age,there were differences in fluoride exposure levels among some age groups.There were age differences in the levels of nail-fluoride exposure,while there were no gender differences in the levels of hair and nail-fluoride exposure.The distribution of human fluorine exposure levels in the three regions is different from the distribution rules of residents' age,height and weight,but the increase of age,height and weight has a certain promoting effect on the degree of fluorine exposure.Under certain conditions,the distribution characteristics of human fluorine exposure can be identified from human fluorine exposure level.(4)When coal roasted pepper is ingested orally,the influence rate of fluorine content on human fluorine exposure level is greater than 1,which has a very serious influence on human daily fluorine exposure;After the high-temperature combustion of coal,clay,coal + clay and other substances,the released fluorine ACTS on the human body through the respiratory pathway.The influence rate of these substances on the human body's fluorine exposure level is much higher than 1,among which the influence rate of coal + clay is the highest,directly affecting the human body's fluorine exposure level.Therefore,the coal roasted pepper and coal + clay in the three fluorosis areas are important fluorine "sources" for the occurrence of coal-burning fluorosis.It is suggested that the residents in the disease area should use the method of drying hot pepper instead of coal roasting or washing the hot pepper before eating coal roasting,and choose the coal-fired stove outside the chimney to reduce the accumulation of fluoride after it is effectively absorbed by human body,which can effectively prevent and control the prevalence and degree of coal-burning fluorosis.(5)A health risk assessment shows that the fluorine content of drinking water in the region is lower than the national health standard and there is no risk to human health;Topsoil health risks are distributed differently in different regions.Red clay hilly regions are distributed in the whole region,and coal measure stratigraphic regions are mainly concentrated in the central region.The clay THQ(>1)is the highest in the exposed areas of carbonate rocks and the hilly areas of red clay.There are health risks of fumigated chili in coal measure strata and exposed carbonate strata,and there are health risks of baked corn in some coal measure strata. |
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