Fate Of Phosphate Research Articles

The Fate of Phosphate: Assessing Dietary Intake and Urinary Excretion in Swedish Adolescents

BackgroundA high total phosphorus (P) intake has been proposed to promote endothelial dysfunction and atherosclerosis. A diet rich in foods containing P additives could contribute to an excessive intake, potentially reflected as increased concentration of P in urine. ObjectivesThis study aimed to assess the intake of total dietary P, P additives, and its sources and examine their correlation with urinary P in a cross-sectional national study in Swedish adolescents. MethodsWe constructed a database of P additives and applied it to the foods consumed by 3099 participants in the representative school-based dietary survey Riksmaten Adolescents 2016–17. Intake of total dietary P and P additives were assessed using two 24-h recalls. Urinary P was analyzed in a subsample of 756 participants using inductively coupled plasma mass spectrometry. Spearman rank correlation (ρ) was used to assess the association between dietary P intake and urinary P excretion. ResultsThe mean (SD) intake of total P was 1538 (±667) mg/d. Food containing P additives were consumed by 92% of adolescents and the median (IQR) intake was 49 (22–97; range: 0.01–947) mg/d, corresponding to 5% (1%–6%; range: 0%–50%) of total P. The main contributing food to P additives was cola drinks, while the main contributing food group was sausage dishes. Total P intake was weakly correlated with urinary P (ρ = 0.12; P < 0.01) but not with intake of P additives. ConclusionsNearly, all participants consumed P additives, contributing to an average of 5% of total P intake but ranging up to 50%. The intake of total P, but not P additives, was weakly reflected in the urinary P. Access to more comprehensive information on P additives in foods would improve further evaluation of potential health consequences.

299 Fate of Phosphate

299 Fate of Phosphate

Phosphorus within planetary boundaries

ABSTRACTIn this paper the screening calculations of the removal time of phosphorus from water bodies of federal districts of Russia are presented. Calculations are made using the matrix algebra based approach and are applied as a tool for the estimation of the fate of phosphates in different environmental media (water, air, soil, biota, etc.). The results show that the use of phosphate fertilizers is sometimes quite high in the most vulnerable federal districts. It means that the application of fertilizers in order to increase the yield of agriproducts should be accompanied by detailed assessment of the risks of eutrophication. Calculations have shown high vulnerability in the district of the Lake Baika.

Desorption mechanisms of phosphate from ferrihydrite and goethite surfaces

The fate of phosphate in the environment is governed by reactions at particle surfaces. These adsorption and desorption reactions display biphasic kinetics involving an initial rapid reaction followed by a substantially slower one extending over long time periods. In this study we have investigated the molecular mechanisms of desorption kinetics of phosphate from ferrihydrite and goethite nanoparticles in the absence of competing ligands. Desorption was studied by means of in-situ infrared (IR) spectroscopy over a wide pH range and a time period of 24h. The spectroscopic data sets were subjected to multivariate curve resolution alternating least squares (MCR-ALS), which enabled the resolution of surface species characterized by unique IR spectra together with their corresponding kinetic profiles. The desorption results showed the typical biphasic behavior and that increasing positive surface charge of ferrihydrite and goethite slowed down desorption of the negatively charged phosphate ions. Moreover, diprotonated phosphate desorbed faster than monoprotonated phosphate at a given pH. At circumneutral pH values desorption from ferrihydrite was substantially faster as compared to goethite, and this could be ascribed to electrostatic effects and differences in charging between ferrihydrite and goethite. The collective desorption results were explained by a model, consisting of a series monodentate phosphate surface complexes in different protonation states, in conjunction with a description that accounts for the electrostatic effects on desorption kinetics at charged mineral-water interfaces. The fast and slow desorption followed directly from this model and indicated that biphasic kinetics can be caused by a single phosphate surface complex as a result of decreasing surface coverage along with the lateral repulsive interactions between adsorbed phosphate groups. Hence, in contrast to previous models our study has shown that biphasic desorption kinetics do not have to involve several different structural complexes related to either weak and strong sites or a distribution of phosphate between external surfaces and mineral pores.

Adsorption of phosphate on pure and humic acid-coated ferrihydrite

Purpose Humic acid and mineral oxides are simultaneously present in soils and can form organomineral complexes. These complexes can influence the transport and fate of phosphate in the environment. The objective of this study was to investigate the adsorption of phosphate on these complexes by comparing them with phosphate adsorption on only the mineral.

Fate of phosphate and nitrate in waters of an intensive agricultural area in the dry zone of Sri Lanka

The chemistry of surface waters and groundwater draining agricultural catchments in the north-central and northwestern areas of Sri Lanka is described. Hydrochemical data from 296 water samples are used to evaluate water quality and to identify the processes that control nitrate and phosphate concentrations in the water. The results indicate that nutrient concentrations in the groundwaters are greater than those in the surface waters. Increased nutrient levels were observed in groundwater in a selected area in the fortnight following fertilizer application. Detailed geochemical investigations of selected groundwater samples reveal a gradual rise of nitrate–N and other solutes along the horizontal flow direction. Compared to the application rates of fertilizer in the area, the average nutrient concentrations in all waters are relatively low (1.5 mg/l nitrate and 0.5 mg/l phosphate) and stable. The results suggest that prevailing reducing conditions, iron-rich overburden soil cover and manmade canal networks control nutrient accumulation in the groundwater.

The fate of phosphate in an in situ Lagrangian addition experiment in the Eastern Mediterranean

The Eastern Mediterranean is the largest oceanic ecosystem that is phosphate-limited. To determine the impact of a transient input we executed a phosphate addition experiment in the surface waters of the Cyprus Eddy (33.31N 32.31E), and compared the ecosystem response with surrounding unperturbed water. A tracer, sulphur hexafluoride (SF6), added with the phosphate, enabled tracking of the patch when phosphate concentration declined to detection limits, and provided quantitative estimates of mixing, dilution and patch volume. The patch expanded to 4400 km 2 over 9 days with a lateral diffusion rate of 237 2m 2 /s that was consistent with previous tracer releases in eddies. Mixed layer phosphate concentration was � 110 nmol/l immediately post-release, and declined to o5 nmol/l after 6 days. A phosphate budget was developed using SF6 as a proxy to discriminate between dilution and biological pathways, with dilution resulting in loss of � 75% of added phosphate from the patch centre by day 3. Non-conservative phosphate loss was largely due to biological incorporation into particulate-P, of which 50% accumulated at the patch centre whilst the remainder was removed by lateral dilution by day 3. Non-conservative phosphate loss at the patch centre was 15–15.5 nmol/l by day 4, which was equal to the cumulative biological P uptake of 15.6 (75.6) nmol/l P and concurred with two other independent estimates of P uptake. This closure of the phosphate budget infers that the transfer of added P to mesozooplankton and higher consumers was not significant within the timescale of the experiment, despite the observed biomass increase that followed phosphate addition. Although patch dilution significantly reduced phosphate concentration and particulate accumulation, and so the apparent biological response to the added phosphate, analysis suggests that lateral mixing would not prevent bacterial biomass accumulation at the growth rates observed, suggesting that another factor such as grazing was responsible.

Phosphorus retention in sediments1

Phosphate is usually the most important growth limiting nutrient in aquatic environments. The availability of P is the result of external load and retention in the sediments. This latter is the result of a number of transport, microbial and chemical processes. The role of P in the productivity in systems and in the eutrophication process has initiated a large number of studies to the behaviour of P in sediments. Case studies in Veluwemeer, IJsselmeer, Wadden Sea and German Bight show that sorption on and binding in ferric (oxi)hydroxides, occlusion in calcium carbonates and authigenic mineral formation are the most important retention processes. However, all this research did not result in totally new approaches in lake restoration, nor did knowledge of internal P loading result in large scale applications of well-known sediment restoration techniques. It did result in more realistic expectations of lake restoration programmes. At the same time, renewed interest in the overall role of phosphate in the functioning and productivity of systems is emerging. The most important new items are: the role of the productivity is examined at large scale levels; the coupling of productivity with several large scale material cycles and global environmental problems and the study of the behaviour and fate of phosphate within the context of the functioning of entire watersheds.

The fate of phosphate under anoxic conditions in biological nutrient removal activated sludge systems

The nitrogen removal potential of phosphate accumulating organisms under anoxic conditions has been evaluated using a laboratory scale sequencing batch reactor fed with synthetic wastewater and operated in a sequence of anaerobic, anoxic and aerobic periods. The phosphate uptake rate under anoxic conditions was lower than that under aerobic conditions. However, in the presence of an external substrate such as glucose and acetate, the fate of phosphate was dependent on the substrate type; phosphate release occurred in the presence of nitrate as long as acetate was present and glucose did not cause any phosphate release. The nitrate uptake rate was also much lower with glucose than acetate. The results implied that poly-hydroxyalkanoates could be oxidized by nitrate and phosphate uptake during the anoxic phase should be introduced into process modeling. © Rapid Science Ltd. 1998

Phosphorus retention in sediments

Phosphate is usually the most important growth limiting nutrient in aquatic environments. The availability of P is the result of external load and retention in the sediments. This latter is the result of a number of transport, microbial and chemical processes. The role of P in the productivity in systems and in the eutrophication process has initiated a large number of studies to the behaviour of P in sediments. Case studies in Veluwemeer, IJsselmeer, Wadden Sea and German Bight show that sorption on and binding in ferric (oxi)hydroxides, occlusion in calcium carbonates and authigenic mineral formation are the most important retention processes. However, all this research did not result in totally new approaches in lake restoration, nor did knowledge of internal P loading result in large scale applications of well-known sediment restoration techniques. It did result in more realistic expectations of lake restoration programmes. At the same time, renewed interest in the overall role of phosphate in the functioning and productivity of systems is emerging. The most important new items are: the role of the productivity is examined at large scale levels; the coupling of productivity with several large scale material cycles and global environmental problems and the study of the behaviour and fate of phosphate within the context of the functioning of entire watersheds.

Comparison of Phosphorus Dynamics in Two Oklahoma Reservoirs and a Natural Lake Varying in Abiogenic Turbidity

The rate of phosphate uptake, the immediate fate of phosphate, and the potential rate of release of phosphate from dissolved phosphorus compounds in epilimnia of two reservoirs and one natural lake in northcentral Oklahoma were compared in the summer and in the late autumn. Sangre Isle Lake is a highly productive eutrophic impoundment, Sanborn Lake is a natural lake with low phytoplanktonic productivity, and Boomer Lake is an impoundment with modest productivity that is heavily affected by clay suspensoids. Although the uptake of phosphate (radiometrically determined) was rapid in each of these lakes in summer, the fate of phosphate in Boomer Lake differed from that of the others, with much of the phosphate sorbing to suspended silts and clays rather than biota (determined by isopycnic sedimentation). Recycling of phosphate from phosphomonoesters was greatest in Sangre Isle Lake, moderate in Sanborn Lake, but was undetectable in Boomer Lake. These findings suggest that high concentrations of clay suspensoids influence the epilimnetic P dynamics in reservoirs and lakes.

Iron Phosphate and Anaerobic Digestion

Abstract This research was undertaken in order to clarify some of the apparent inconsistencies in the literature concerning the fate of phosphates in iron phosphate sludges during anaerobic digestion. Three anaerobic batch reactors were started and acclimatized to a feed of waste activated sludge. While one digester was maintained as a control, with a feed of only biological sludge, the other two digesters were loaded with different mixtures of biological sludge and iron phosphate sludge. When the digesters had stabilized with respect to influent and effluent total phosphorus, critical measurements of all the phosphorus fractions were made. The soluble phosphorus in the control digester remained the same from the influent to the effluent. This observation seems to contradict the expected increase in soluble phosphates during the anaerobic digestion process. When the activated sludge was mixed with the ferric phosphate sludge, it was observed that a reduction in soluble phosphorus took place. After this combined biological-chemical sludge had been digested anaerobically, an increase in the soluble phosphorus concentration, to a level roughly equivalent to that in the biological component of the influent, was observed.

Anaerobic Phosphate Uptake by Barley Plants

Considerable uptake of phosphate by both the shoot and root has been demon strated for young barley plants with their roots in anoxic culture solution at con centrations of i to io pM orthophosphate. Consideration of the free space and passive transpirational uptake indicates an accumulatory process, and the immediate efflux caused by respiratory inhibitors supports this. Shoot uptake is much less at higher external concentrations of phosphate and at o-i mM was only 14 per cent of the control. The root accumulation process was unimpaired at an external concentration of 1 pM phosphate when the whole plant was subjected to anaerobic conditions (shoot illuminated) but under similar conditions at a concentration of 100 pM a considerable efflux of phosphate occurred. Analysis of the fate of phosphate taken up from anoxic solution of phosphate (10 pM) indicated that there was a reduction in the level of inorganic phosphate after 4-5 h and steady rise in sugar phosphates up to 6 h with a marked increase in the levels of glucose-6-phosphate, fructose-6-phosphate, and the phosphoglycerate fraction.

The Pyruvate-Phosphate Dikinase Reaction: The Fate of Phosphate and the Equilibrium

Abstract An enzyme capable of catalyzing the reaction AMP + PPi + P-enolpyruvate ⇌ ATP + Pi + pyruvate was obtained from Bacteroides symbiosus cell extracts and was purified from interfering enzyme activities. It was strongly stimulated by ammonium ion. In this respect and in other physical properties the bacterial enzyme differed from that previously obtained from Entamoeba histolytica. In a complete reaction system the enzyme transferred label from orthophosphate to pyrophosphate and to the γ position of ATP while the label of 32P-enolpyruvate was transferred to the β position of ATP. The observed equilibrium constant catalyzed by the bacterial enzyme was directly dependent upon the square of the hydrogen ion concentration. At pH 7.0 its value was 1140. Apparent Km values for P-enolpyruvate and pyrophosphate were 0.07 mm and 0.1 mm for the amebal enzyme and 0.06 mm and 0.1 mm for the bacterial enzyme, respectively.

Effect of colchicine on the nitrogen metabolism and fate of phosphates absorbed during the formation of fungal felts of cunninghamella sp.

During formation of fungal mats of Cunninghamella sp., colchicine seemed to have no effect on the mycelial dry weight but increased the phosphorus and nitrate uptake only when present in 20 p.p.m. All treatments increased the organic phosphorus content and peptide fraction of the tissue medium systems. These phenomena were furthered by raising the concentration of the drug. Colchicine showed its inhibitory effects on protein synthesis only when administered in the high concentration. The mechanism of nitrate utilisation in presence of colchicine was also discussed.