- 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.
Use of Toothpaste and Toothbrushing Patterns Among Children and Adolescents - United States, 2013-2016.
Fluoride use is one of the main factors responsible for the decline in prevalence and severity of dental caries and cavities (tooth decay) in the United States (1). Brushing children's teeth is recommended when the first tooth erupts, as early as 6 months, and the first dental visit should occur
Fluoride intake from beverage consumption in a sample of North Carolina children.
Since the 1940's, the prevalence of dental fluorosis has increased in the US, concomitant with a reduction in dental decay. These changes have been attributed in part to the widespread use of systemic and topical fluorides. Various sources of increased systemic fluoride exposure have been investigated. However, little is known regarding fluoride intake from beverages
Risk of enamel fluorosis in nonfluoridated and optimally fluoridated populations: considerations for the dental professional.
BACKGROUND: Few studies have evaluated the impact of specific fluoride sources on the prevalence of enamel fluorosis in the population. The author conducted research to determine attributable risk percent estimates for mild-to-moderate enamel fluorosis in two populations of middle-school-aged children. METHODS: The author recruited two groups of children 10 to 14
Estimation of toothpaste fluoride intake in preschool children
The objective of this study was to estimate the intake of toothpaste fluoride used by children aged 2 to 6 years (n=87) treated at a hospital of a medium-sized city (Campina Grande, PB) in the Northeastern region of Brazil. Data regarding sociodemographic characteristics of families and children's toothbrushing were collected from questionnaire-based
Combination of fluoride and endosulfan induced teratogenicity and developmental toxicity in Swiss albino mice exposed during organogenesis.
The present investigation was conducted to evaluate the teratogenic and developmental toxicity of fluoride and endosulfan alone and in combination in pregnant Swiss albino mice exposed during the organogenetic period (5-14 days) of gestation. Fluoride (25.1 mg/kg body weight in water) and endosulfan (1.8 mg/kg bw by oral intubation) when
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