Endemic fluorosis is given rise to by human intake of excess fluorine from environment by way of food chain. In China it is one of the extensively prevalent endemic diseases and its distribution shows clearly regional...Endemic fluorosis is given rise to by human intake of excess fluorine from environment by way of food chain. In China it is one of the extensively prevalent endemic diseases and its distribution shows clearly regional characteristics. In macroscopic sight, three large fluorosis zones may be divided: (1) The arid and semi-arid plains in the north of China. These regions have a dry climate, making fluorine accumulation in the Quaternary deposits. Thus, the drinking water with high content of fluorine is the main cause of the disease formation. (2) The Yunnan-Guizhou Plateau. In the region, rocks and soils rich in fluorine bring about fluorine excess in crop food. This plays an important role in the disease formation. (3) Southeast hills. The hot spring with high content of fluorine leads to fluorosis.The fluorine absorbed by people from the environment is firstly from the drinking water and secondly from the crop food originating from soil. The fluorine in the air can be accumulated in crop leaves to展开更多
This paper deals with some endemic diseases related to selenium, iodine and fluoride in eco-environment. Keshan disease and Kaschin-Beck disease are associated with low selenium, they mainly occur in a belt zone acros...This paper deals with some endemic diseases related to selenium, iodine and fluoride in eco-environment. Keshan disease and Kaschin-Beck disease are associated with low selenium, they mainly occur in a belt zone across China ranging from North-East to South-West. Selenium contents in food grains and human hair from the disease affected areas are usually below 0.020ppm and 0.20ppm respectively. The endemic goitre caused by iodine deficiency distributes extensively in China, mainly in mountainous and hilly districts, swamp and peat areas, some sand soil and limestone areas. Also there is another kind of endemic goitre which caused by iodine excess in interior and coast areas. Endemic cretinism usually occurs in the endemic goitre seriously affected areas. Endemic fluorosis is also widely distributed in China, but mainly occurs in dry or semi-dry areas of north China. The fluoride sources for causing endemic fluorisis are drinking water and food grains polluted by coal smoke in the backing process of maize and chilli.展开更多
Almost half of the total rural area of Guizhou Province and many regions within the 11 adjacent provinces in southwestern China have a long history(at least 70 years) of endemic fluorosis,including dental fluorosis an...Almost half of the total rural area of Guizhou Province and many regions within the 11 adjacent provinces in southwestern China have a long history(at least 70 years) of endemic fluorosis,including dental fluorosis and osteofluorosis along with its associated deformities and disabilities.Over decades of research,this specific type of endemic fluorosis has been defined as coal-burning fluorosis,which is distinct from drinking-water fluorosis.It is generally acknowledged that indoor burning and combustion of high-fluorine coal leads to food contamination,and fluorine then enters the human body.However,the exact chemical form of fluorine during its release and transfer to the body is still unknown.In the present study,21 domestic coal samples from outcrop and semi-outcrop coal collected in five villages with fluorosis were analyzed by time-of-flight secondary ion mass spectrometry(TOF-SIMS).The total mass fraction of sulfur in the samples ranged from 0.24%-5.58% and total fluorine content ranged 90.2-149.2 mg/kg.H3O+,H2SO4+ and HSO4-were detected in the samples by TOF-SIMS,which indicated that sulfuric acid hydrate(H2SO4.H2O) was present in the samples.F-was detected in all of these,which suggested the samples contain ionic fluorine compounds.Under certain circumstances,such as heating or burning,the prevalence and coexistence of the acid(H2SO4.H2O) and base(F-) would lead to a neutralization reaction producing volatile hydrogen fluoride(HF,bp = 19.5℃).This would be the chemical form of fluorine released from the coal.Further studies using HF and SO2 test tubes on headspace gas over coal samples heated to 200℃ in the laboratory and on headspace gas over stoves or chimney tops at rural residences confirmed the release of HF.展开更多
文摘Endemic fluorosis is given rise to by human intake of excess fluorine from environment by way of food chain. In China it is one of the extensively prevalent endemic diseases and its distribution shows clearly regional characteristics. In macroscopic sight, three large fluorosis zones may be divided: (1) The arid and semi-arid plains in the north of China. These regions have a dry climate, making fluorine accumulation in the Quaternary deposits. Thus, the drinking water with high content of fluorine is the main cause of the disease formation. (2) The Yunnan-Guizhou Plateau. In the region, rocks and soils rich in fluorine bring about fluorine excess in crop food. This plays an important role in the disease formation. (3) Southeast hills. The hot spring with high content of fluorine leads to fluorosis.The fluorine absorbed by people from the environment is firstly from the drinking water and secondly from the crop food originating from soil. The fluorine in the air can be accumulated in crop leaves to
文摘This paper deals with some endemic diseases related to selenium, iodine and fluoride in eco-environment. Keshan disease and Kaschin-Beck disease are associated with low selenium, they mainly occur in a belt zone across China ranging from North-East to South-West. Selenium contents in food grains and human hair from the disease affected areas are usually below 0.020ppm and 0.20ppm respectively. The endemic goitre caused by iodine deficiency distributes extensively in China, mainly in mountainous and hilly districts, swamp and peat areas, some sand soil and limestone areas. Also there is another kind of endemic goitre which caused by iodine excess in interior and coast areas. Endemic cretinism usually occurs in the endemic goitre seriously affected areas. Endemic fluorosis is also widely distributed in China, but mainly occurs in dry or semi-dry areas of north China. The fluoride sources for causing endemic fluorisis are drinking water and food grains polluted by coal smoke in the backing process of maize and chilli.
基金supported by the State Scholarship Fund by China Scholarship Council (2007106398)the Key Project of the National Science & Technology Pillar Program (2006BAK03A21)
文摘Almost half of the total rural area of Guizhou Province and many regions within the 11 adjacent provinces in southwestern China have a long history(at least 70 years) of endemic fluorosis,including dental fluorosis and osteofluorosis along with its associated deformities and disabilities.Over decades of research,this specific type of endemic fluorosis has been defined as coal-burning fluorosis,which is distinct from drinking-water fluorosis.It is generally acknowledged that indoor burning and combustion of high-fluorine coal leads to food contamination,and fluorine then enters the human body.However,the exact chemical form of fluorine during its release and transfer to the body is still unknown.In the present study,21 domestic coal samples from outcrop and semi-outcrop coal collected in five villages with fluorosis were analyzed by time-of-flight secondary ion mass spectrometry(TOF-SIMS).The total mass fraction of sulfur in the samples ranged from 0.24%-5.58% and total fluorine content ranged 90.2-149.2 mg/kg.H3O+,H2SO4+ and HSO4-were detected in the samples by TOF-SIMS,which indicated that sulfuric acid hydrate(H2SO4.H2O) was present in the samples.F-was detected in all of these,which suggested the samples contain ionic fluorine compounds.Under certain circumstances,such as heating or burning,the prevalence and coexistence of the acid(H2SO4.H2O) and base(F-) would lead to a neutralization reaction producing volatile hydrogen fluoride(HF,bp = 19.5℃).This would be the chemical form of fluorine released from the coal.Further studies using HF and SO2 test tubes on headspace gas over coal samples heated to 200℃ in the laboratory and on headspace gas over stoves or chimney tops at rural residences confirmed the release of HF.
