Fluoride levels in seven commercial phosphate fertilizers (four single superphosphate samples, two diammonium phosphate samples, and one ammonium nitrophosphate sample) were analyzed independently at three laboratories employing the techniques of ion chromatography and ion-selective electrode. The results were consistent for aqueous solutions containing 100?mg?L?1 (ppm) of fertilizer. The average values of fluoride from four different studies varied from 0.140?±?0.006–1.33?±?0.158% (w/w) for the seven fertilizer samples. The [P2O5]/[F] ratios (w/w) were computed for all the seven samples and the values were in the range of 13.79–328.57. By comparing these values with the average [P2O5]/[F] ratio in phosphate rock, it was inferred that 3–75% of fluoride originally present in rock remained in the fertilizers. IR spectral data revealed a small peak at 716?cm?1 – indicative of SiF62? – in the sample containing lowest fluoride which may be on account of fluoride stripping of intermediate phosphoric acid with reactive silica in this case. Considering 15 MMT (million metric tons) of annual consumption of phosphate fertilizers in India, the incremental load of fluoride in agricultural fields was estimated to be 127,650?±?14,550 MTy?1 based on the grand average fluoride content of 0.851?±?0.097% (w/w). While a part of this fluoride would likely get discharged into oceans through run-off, the remainder may persist in the soil, some amount may accumulate in vegetation, and a part might find its way into fresh water bodies, thereby aggravating the fluoride problem in the Country. The problem of non-point source pollution can be reduced by eliminating fluoride at source, and utilizing the recovered fluoride as feedstock. This could, in principle, satisfy the entire requirement of the fluorochemicals industry in India. Environmental costs need to be factored in while making an assessment of the viability of fluoride recovery and reuse in this manner compared to production from virgin sources of fluoride.
Two New Members of CsFEXs Export Fluoride Coupled Proton Gradients and Participate in Reducing the Fluoride Accumulation in Low-Fluoride Tea Cultivars
The accumulation of fluoride in tea leaves from various cultivars exhibits significant differences. However, the molecular basis and mechanism remains largely unknown. Here, we reported that two genes of CsFEXs (Fluoride export genes in C. sinensis), CsFEX1 and CsFEX2 transport fluoride out of cells, alleviate the cellular fluoride toxin and
The Use of “Salufer” (Silico-Fluoride of Soda) as an Antiseptic
Excerpt BY A. W. MAYO ROBSON, F.R.C.S., Honorary Surgeon, Leeds General Infirmary; and Lecturer on Practical Surgery at the Yorkshire College. A PERFECT antiseptic for surgical purposes has yet to be found. It must be at the same time a strong germicide, non-poisonous, unirritating to the skin or to the tissues, inodorous, non-volatile, not
Pharmacokinetic aspects of topical fluorides
Pharmacokinetic studies have revealed quantitative information about the bioavailability, rate of absorption, distribution, and clearance of fluoride following the use of fluoride-containing dentifrices, gels, varnishes, and solutions. It is concluded that following the use of topical fluoride products, variable amounts of fluoride are swallowed and absorbed into the systemic circulation--amounts which may be sufficient to produce acute
Slaying sacred cows: is it time to pull the plug on water fluoridation?
Water fluoridation continues to be a contentious public health policy. Recent moves to introduce schemes in England raise important questions about the use of evidence in public policy. Of particular concern is how evidence is used for public health policy-making purposes. This article reviews some of the key debates about
Current problems relating to the pharmacology and toxicology of fluorides.
To the surprise of many, it was not until six years after the repeal of the fluoride law that the Socialstyrelse (National Social Welfare Board) and the responsible Minister for Social Services lngegerd Troedsson started any significant activity to enable the Riksdag (Parliament) to introduce once more a law permitting
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