Combating coal-burning-borne endemic arsenism in Shaanxi Province, Northwest China: The impact of high-arsenic coal ban, improved cook-stoves, and health education.

To eliminate the epidemic of coal-burning-borne endemic arsenism (CBBA), our study organized and implemented comprehensive measures including high-arsenic coal ban, improved cook-stoves, and health education. We also aimed to promote the application value of these measures in preventing and controlling CBBA to the world. From 2004 to 2005, through a stratified random sampling method, we selected 58,256 individuals to investigate the prevalence of CBBA and the arsenic levels in 1287 environmental and biological specimens. The prevalence of CBBA was 19.26 % and significantly associated with the arsenic levels in coal, pepper, corn and hair, which were at or exceeded national upper limits. To timely prevent and control the disease, the comprehensive measures have been implemented since 2005 to present. Comparison and correlation analyses were utilized to evaluate the effectiveness of these measures in reducing the prevalence of CBBA. According to statistics, 73 high-arsenic coal mines were banned and over 99 % households in endemic areas accepted stove improvements and diversified health education. Monitoring studies during 2010-2019 has confirmed that these measures led to a decrease in urine arsenic levels among endemic residents, and they developed novel dietary practices, such as properly drying, storage, and washing of food. Additionally, the awareness rate of CBBA increased from less than 70 % to over 95 %. Finally, the prevalence of CBBA has decreased to 0.153 % investigated by a census involving 2.076 million endemic residents in 2019. In summary, CBBA in northwest China has been successfully controlled through banning on high-arsenic coal, introducing improved cook-stoves, and providing health education.

[Detection of serum PICP and PINP and COL1alpha1 DNA sequence analysis in patients with arsenic poisoning in Dazhuyuan Town, Ankang area in southern Shaanxi Province].

OBJECTIVE: To investigate type I collagen metabolism in patients with arsenic poisoning in Dazhuyuan town, Ankang area in southern Shaanxi province known for high-level exposure to arsenic (As), fluoride (F) and selenium (Se). METHODS: This case-control study involved 29 patients with arsenic poisoning from Dazhuyuan, a town in Ankang area of Shaanxi province affected by coal-borne endemic arsenicosis. Thirty individuals without arsenic poisoning from Chang'an county of Xi'an city were included as the control group. The serum concentrations of As and Se were determined using a graphite furnace atomic absorption spectrophotometer, and the levels of F detected with a fluoride ion-selective electrode. Enzyme-linked immunosorbent assay (ELISA) was used for assessing serum contents of PICP and PINP, and the sequence of COL1alpha1 gene was analyzed with ABI sequence analyzer. RESULTS: The contents of PICP and PINP were similar between the two groups, which had also identical COL1alpha1 DNA sequences. After controlling for all the other factors, an inverse correlation was noted between PICP and serum F contents (r=-0.4, P<0.05) and between PINP and hair F content (r=-0.5, P<0.05), but a positive correlation was found between PINP and hair Se content (r=0.5, P<0.05). CONCLUSION: Hair F and Se levels are the major factors affecting PINP synthesis, and increased hair F level is associated with elevated PINP content, whereas hair Se level is inversely correlated to PINP content. But in the patients with arsenic poisoning from Dazhuyuan town, the PICP, PINP contents and COL1alpha1 DNA sequence show no significant alterations, suggesting that hair Se increment abolishes the effect of hair F increment in inducing the decrease in PINP content.

[Analysis of risk factors of skin lesions from burning high-arsenic-contaminating coal in southern Shanxi Province].

OBJECTIVE: To explore risk factors of the patients with skin lesions from burning high-arsenic-contaminated coal in southern Shanxi Province. METHODS: An epidemiological cross-sectional study was conducted in two villages of Hanbin District, Ankang City, Shanxi Province, where 198 participants were randomly selected. The parts of factors which were not significantly different were rejected via the single variable analysis and the collinear relationships were removed between the other factors using principal components analysis, and then the major risk factors of the skin lesions from burning high-arsenic-contaminated coal were obtained from stepwise logistic regression. RESULTS: The single variable analysis showed that 11 influential variables were significantly associaed with coal-burning-arsenic-associated skin lesions, while principal component and logistic regression analysis showed that 6 variables could be the principal, which were period of burning arsenic-contaminating coal, ege, the arsenic content in blood, resident duration, the arsenic content in urine and hair, respectively. CONCLUSION: The results suggested that the major risk factors of the skin lesions related to burning coal-contaminating arsenic should be period of burning arsenic-contaminating coal, age, the arsenic content in blood, resident duration, the arsenic content in urine and hair.

Screening high-fluoride and high-arsenic drinking waters and surveying endemic fluorosis and arsenism in Shaanxi province in western China.

The objectives of this study were to screen high-fluoride and high-arsenic drinking waters, to evaluate the effectiveness of fluoride-reducing projects and to assess the present condition of endemic fluorosis and arsenism in Shaanxi province in western China. For screening high-fluoride drinking waters, five water samples were collected from each selected village where dental fluorosis patients were detected in 8-12 year-old children. For evaluating the effectiveness of fluoride-reducing projects, four water samples were collected from each project at end-user level. Fluoride concentrations in water samples were measured by fluoride-selective electrode method or spectrophotometry. Dental fluorosis in children aging 8-12 years was examined according to Horowitz's Tooth Surface Index of Fluorosis. Skeletal fluorosis in adults was detected clinically and radiologically according to Chinese Criteria of Clinical Diagnosis of Skeletal Fluorosis. For screening high-arsenic waters, 20 water samples were collected from each village which was selected from areas characterized by the geographic features to induce high-arsenic underground water, i.e., alluvial plains, ore mining or smelting areas, geothermal artesians, and thermal springs. Arsenic concentrations in water samples were determined by spectrophotometry or arsine generation atomic fluorospectrophotometry. Arsenism in adults aging 40-89 years was examined in villages with arsenic concentrations in drinking water above 0.05 mg/l according to Chinese Criteria for Classification of Endemic Arsenism Areas and Clinical Diagnoses of Endemic Arsenism. The results showed that the fluoride level of 7144 water samples was 1.17 +/- 0.93 mg/l. There were 3396 (47.6%) high-fluoride waters (fluoride level was above 1.0 mg/l) distributing in 786 (45.1%) villages, where about 0.8 million (50.0%) people inhabited. Additionally, the 1315 fluoride-reducing projects were studied. The fluoride level of the projects was 2.79 +/- 1.09 and 0.98 +/- 0.47 mg/l before and after building the projects, which remained at relatively lower level (1.03 +/- 0.47 mg/l). But there were still 58.0% of the projects providing drinking waters with fluoride concentrations beyond 1.0mg/l. The rates of dental fluorosis and skeletal fluorosis were 38.2% and 11.8%, respectively. The arsenic level of 1732 water samples was 0.010 +/- 0.082 mg/l. There were 174 (14.9%) high-arsenic waters (arsenic level was above 0.010 mg/l) being detected, distributing in 41 (38.7%) villages. The arsenic level in 53 (4.5%) water samples was beyond 0.025 mg/l. There were 3 villages with arsenic level in drinking water beyond Chinese National Permissible Limits (0.050 mg/l), and the prevalence rate of arsenism reached 37.0% in these three villages, 3.7%, 22.2%, and 11.1% of subjects suffering from mild, moderate, and severe arsenism, respectively. Conclusively, the wide distribution of high-fluoride drinking waters contributes to the prevalence of dental and skeletal fluorosis in Shaanxi province and the quality of fluoride-reducing projects should be further improved. Ore mining and smelting induces high-arsenic drinking waters, resulting in arsenism prevalence in Shang-luo city. Proper measures should be taken to deal with water pollution in the ore mining and smelting areas in order to solve the high-arsenic water problem in Shaanxi province.

[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.