[Spatial Variation and Influencing Factors of Soil pH in Anshun City].

Exploring the spatial distribution characteristics and variation law of soil pH and analyzing the impact of environmental factors on the spatial differentiation of soil pH are of great significance to the accurate management of soil pH and the sustainable utilization of soil resources in the complex mountainous environment of Anshun City. Based on 22 851 field sampling points, using the methods of global Moran's I index, cold and hot spot analysis, semi-variance function, and Kriging interpolation, the spatial structure characteristics and distribution law of soil pH in Anshun City were revealed from different angles, and the influence of environmental factors on its spatial differentiation was analyzed with the help of geographic detectors. The results showed that:① the variation range of topsoil pH value in Anshun City was 3.56-8.61, the mean value was 6.28, and the coefficient of variation was 16.33%. ② In the global space, soil pH showed aggregation distribution; in the local space, the west and northwest were hot spots, whereas the east and south were cold spots. The nugget coefficient (40.19%) showed that the spatial variability in soil pH was determined by both structural and random factors, but the role of structural factors was greater. ③ In terms of spatial distribution, soil pH mainly presented a patchy mosaic distribution pattern, in which slightly acidic soil (57.14%) was concentrated in the east, northeast, and south of Anshun City; neutral soil (30.13%) was concentrated in the west, northwest, and southeast; and strongly acidic soil (6.12%) and alkaline soil (6.45%) were embedded in slightly acidic soil and neutral soil, respectively, in a block structure. ④ The geo-detector analysis showed that the explanatory power of various environmental factors to the spatial variation in soil pH was ranked as soil type (9.4%)>soil forming parent rock (7.9%)>altitude (2.1%)>land use (1.8%)>slope (0.1%), in which the q value of the interaction between soil type and parent rock type and other factors was large. Therefore, soil type and parent rock type were the main controlling factors of soil pH spatial variation in Anshun City.

[Environmental and geochemical behaviors of fluorine and its impacts on ecological environment]. / æ°Ÿçš„çŽ¯å¢ƒåœ°çƒåŒ–å­¦è¡Œä¸ºåŠå ¶å¯¹ç”Ÿæ€çŽ¯å¢ƒçš„å½±å“.

In past decades, fluorine exposure of plants and human caused by regional geochemical anomalies of fluorine or environmental pollution has received widespread concerns. Many in-depth researches have been conducted on the geochemical behavior of fluorine in different environmental media, but with disputes and uncertainties. We reviewed the research advances on geochemical behaviors of fluorine in the atmosphere, water and soil, including source, quantity, existence form, migration, transformation, and controlling factors. The observation of correlation between geochemical behaviors of fluorine and plant and human fluoride exposure was also reviewed. Moreover, we proposed that the future research on environmental geochemical behaviors of fluorine should give priority to particular directions.

[Biological exposure limits caused by co exposure to fluoride and arsenic based on Wnt signaling pathway]. / 基于Wntä¿¡å·é€šè·¯æŽ¢è®¨æ°Ÿç ·æ··åˆæš´éœ²çš„ç”Ÿç‰©æš´éœ²é™å€¼.

Chronic fluoride-arsenic combined poisoning is a global public health problem. While the cause of the disease is clear, the pathogenesis is unknown. Given that there is no specific treatment, early prevention is particularly important. Biological exposure limits are designed to investigate the maximum allowable concentration of harmful effects from exogenous chemicals. To explore the biological exposure limits for mixed exposures of fluoride and arsenic, we compared the contents of fluorine and arsenic in the environmental media of the control and fluoride-arsenic combined exposure areas and analyzed the dose-effect and dose-response relationship between fluoride, arsenic and the key proteins of Wnt signaling pathways. The benchmark dose method was used to estimate the biological exposure limit for fluoride-arsenic combined exposure. The results showed that the content of fluoride in coal, clay, indoor air, outdoor air, chili and rice, as well as arsenic content in coal, clay, outdoor air, chili and rice was higher than that of the control. With the increase of fluoride and arsenic exposure levels, the glycogen synthase kinase 3β (GSK3β), β-catenincontents and the prevalence of Wnt/β-catenin signaling pathway antagonistic protein Dickkopf-1 (DKK1), GSK3β, Beta-catenin (β-catenin) gradually increased, but the content of DKK1 significantly decreased. Based on the Wnt signaling pathway, the biological exposure limit for fluoride-arsenic combined exposure was urinary fluoride of 0.52 mg·g-1 creatinine and urinary arsenic of 6.59 mg·g-1 creatinine. Our results had important guiding significance for early prevention of body damage caused by fluoride-arsenic combined poisoning.

[Relationship between fluoride exposure, orthopedic injuries and bone formation markers in patients with coal-burning fluorosis]. / ç‡ƒç ¤æ±¡æŸ“åž‹æ°Ÿä¸­æ¯’æ‚£è€ æ°Ÿæš´éœ²ã€éª¨ç›¸æŸä¼¤ç¨‹åº¦ä¸Žéª¨å½¢æˆæ ‡å¿—ç‰©çš„å ³ç³».

Chronic exposure to fluoride is a public health problem worldwide. We explored the relationship between fluoride exposure, orthopedic injuries and bone formation markers alkaline phosphatase (ALP), bone Gla protein (BGP) in participants with coal-burning fluorosis in Hehua Village (coal-burning fluorosis endemic area) in Zhijin County of Guizhou Province and Zhangguan Village (non-fluoride contaminated area) in Anshun City of Guizhou Province. Environmental samples were collected and fluoride contents were examined using a fluoride ion-selective electrode. Dental fluorosis and skeletal fluorosis of 295 participants from Hehua Village and 85 participants from Zhangguan Village were diagnosed with informed consent. Urinary samples and peripheral blood samples were collected from the participants to determine urinary fluoride (UF), ALP acti-vity, and BGP content. The results showed that fluoride contents in rice, pepper, corn, drinking water, clay, vegetable-grown soil, coal and indoor and outdoor air were significantly higher than those in the control area, but lower than the previously reported values. With the increases of UF concentration, the ALP activity and BGP content significantly increased, the severity of skeletal fluorosis was greater, but with no significant changes in dental fluorosis. There was positive correlation between the severity of skeletal fluorosis and ALP activity, BGP content. These results indicated that low fluoride exposure could cause orthopedic injuries. ALP and BGP could be used to eva-luate the bone turnover in patients with skeletal fluorosis, which would be useful in the auxiliary diagnosis and therapeutic evaluation of skeletal fluorosis.

Effects of land use and parent materials on trace elements accumulation in topsoil.

To determine the effects of parent material and land use on the concentration of trace elements in the agricultural topsoil of Guizhou Province, China, a total of 584 agricultural topsoil samples were collected in a typical region. The results indicate that the contents of trace elements (As, Cd, Cr, Hg, and Pb) in agricultural soils were greater than in the uncultivated soils, and the paddy fields exhibited higher contents of trace elements than dry lands. The enrichments of most trace elements in agricultural topsoil derived from carbonate rock were more serious. In paddy fields, Cd, Cr, and As showed positive relationships with soil organic matter ( < 0.01) but were not affected by pH, carbon-to-nitrogen (C/N) ratio, and clay ( > 0.05). Lead and Hg formed the second component in principal component analysis (PCA) and were closely related to pH and clay content. In dry lands, the trace elements were well correlated with pH, C/N, and clay ( < 0.05). Analysis of PCA and correlation showed that Cd, Cr, and Hg were mainly derived from inorganic fertilizers, whereas Pb and As were primarily from organic manures. These results suggest that the effect of anthropogenic activities on paddy fields is more serious than on dry lands. Parent materials not only serve as sources of soil trace elements but also control the loss and accumulation of trace elements by affecting soil physicochemical properties, especially in dry lands.

[Soil organic carbon variation of de-farming and wasteland during alteration of ecosystem in Billabong].

Four soil profile samples were collected in the middle of de-farming and wasteland billabong and around slopes, located at typical karst district of Guizhou province. Soil organic matter (SOC) content and delta Corg, were determined. SOC content ranged from 6.0 mg x kg(-1) to 92.3 mg x kg(-1), and decreased with depth at slope soil profiles. The range of value was bigger than that at billabong soil profile (6.3-26.7 mg x kg(-1)). The value of detla13 Corg, at slope profiles was between - 25.103% per hundred and - 23.666% per hundred, but variation direction of three slope soil profiles was different. The value of delta 13Corg, in billabong soil profile was between - 23.495% per hundred and - 20.809% per hundred, and increased with depth. The correlation between delta13 Csoc and C4-C,C3-C was significant (R = 0.884, n=7), influenced by new C3-C.