- Regular phosphorus fertiliser inputs (63?years) have significantly increased the amount of fluorine in the topsoil.
- Fluorine has moved and accumulated to a depth of least 50?cm in the soil.
- Fluorine movement wasn’t enhanced by irrigation but moved mainly in drainage after fertiliser application in mid-winter.
An understanding of the rate at which fluorine (F) accumulates in soil from phosphorus fertiliser and how much is lost via leaching are important because of the challenge elevated F may pose to soil, plant and animal health. This study measured F accumulation in a soil under pasture (Inceptisol) that received single superphosphate (SSP) fertiliser over 63?years in a long-term fertiliser trial. It also assessed the downward movement of F in soil and effect of irrigation in a long-term irrigation trial. Results showed total F concentrations in topsoil (0–7.5?cm) that received 188?kg SSP?ha?1 and 376?kg SSP?ha?1 fertiliser increased from 251?mg?kg?1 to 349 and 430?mg?kg?1, respectively. The rates of F accumulation were estimated at 1.1 and 2.1?kg?ha?1?yr?1 respectively, low compared to previous studies. The F concentration in the 376?kg SSP ha?1 treatment decreased with depth, but was significantly higher than the control treatment to 50?cm, suggesting movement of F down the soil. Fluorine concentrations also decreased with depth to 50?cm in soils that received either no irrigation or up to 770?mm?yr?1 from irrigation. However there was no significant difference in the amount of F with depth between irrigation treatments. We postulate that F was moving predominately in drainage water in the period immediately after P fertiliser application in mid-winter and wasn’t enhanced by irrigation. This study should be repeated for other soil types to help our understanding of the potential for ongoing F accumulation in soil and implications this may have on future land use.
Fluoride content of foods made with mechanically separated chicken.
The goal of the present study was to determine the extent to which foods made with mechanically separated chicken can contribute to total fluoride intake. Fluoride content of each blended sample was determined with a fluoride combination electrode following perchloric-acid-facilitated diffusion of hydrogen fluoride. Infant foods had the highest fluoride content followed by chicken sticks, luncheon meats, and canned
Impact of imported beverages on fluoridated and nonfluoridated communities
In order to compare the effect of beverages "imported" from nearby communities on the fluoride intake of a fluoridated community with that of a nonfluoridated community, 45 different carbonated and juice drinks were sampled from Houston (fluoridated) and San Antonio (nonfluoridated) and examined for their fluoride concentrations. In spite of the fact that an
The Dark Side of Fluorine.
Despite the perceived stability of the C?F bond, chemical instability and drug-metabolizing enzymes can lead to its cleavage. The resulting release of fluoride and formation of certain metabolites may cause safety issues and warrant the medicinal chemists’ attention.
Serum fluoride concentrations in renal insufficiency
In an area with non-fluoridated water (F content, 0.061 ppm), serum fluoride concentrations as measured with an ion specific electrode were as follows: controls (N = 13), 0.0127 ppm + 0.0057 (mean + SD); renal insufficiency (N = 10), 0.0452 ppm + 0.0151; chronic hemodialysis (N = 11), 0.0424 +
Dental fluorosis in children in areas with fluoride-polluted air, high-fluoride water, and low-fluoride water as well as low-fluoride air: a study of deciduous and permanent teeth in the Shaanxi province, China.
OBJECTIVE: The aim of the study was to assess dental fluorosis (DF) in the deciduous and permanent teeth of children in areas with high-F coal (area A) and high-F water (area C) compared to children from area B, with low-F water and coal. MATERIAL AND METHODS: 596 children were examined. DF
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