Large Amounts Of Phosphate Research Articles

The D14-SDEL1-SPX4 cascade integrates the strigolactone and phosphate signalling networks in rice.

Modern agriculture needs large quantities of phosphate (Pi) fertilisers to obtain high yields. Information on how plants sense and adapt to Pi is required to enhance phosphorus-use efficiency (PUE) and thereby promote agricultural sustainability. Here, we show that strigolactones (SLs) regulate riceroot developmental and metabolic adaptations to low Pi, by promoting efficient Pi uptake and translocation from roots to shoots. Low Pi stress triggers the synthesis of SLs, which dissociate the Pi central signalling module of SPX domain-containing protein (SPX4) and PHOSPHATE STARVATION RESPONSE protein (PHR2), leading to the release of PHR2 into the nucleus and activating the expression of Pi-starvation-induced genes including Pi transporters. The SL synthetic analogue GR24 enhances the interaction between the SL receptor DWARF 14 (D14) and a RING-finger ubiquitin E3 ligase (SDEL1). The sdel mutants have a reduced response to Pi starvation relative to wild-type plants, leading to insensitive root adaptation to Pi. Also, SLs induce the degradation of SPX4 via forming the D14-SDEL1-SPX4 complex. Our findings reveal a novel mechanism underlying crosstalk between the SL and Pi signalling networks in response to Pi fluctuations, which will enable breeding of high-PUE crop plants.

Phosphate aggregation, diffusion, and adsorption on kaolinite in saline solutions by molecular dynamics simulation

Large amounts of phosphates are required for the survival of cells. However, undesirable algae overgrowth requires phosphorus levels to be kept under control. For large bodies of water, cost-effective and ecosystem-friendly ways to export phosphate are needed. The use of clays appears to be the most promising method in seawater. However, for a broader application, the mechanisms of phosphate adsorption on kaolinite, the conditions for effective flocculation, and the impact of salt must first be addressed. In this study, molecular dynamics simulations are used to determine the adsorption and anchoring mechanisms of two species of phosphates that predominate at neutral pH, the dihydrogen phosphate ion H2PO4− and the hydrogen phosphate ion HPO42−, in a 1:1 ratio, on each of the three kaolinite principal planes, the basal surfaces, octahedral gibbsite (001) and tetrahedral siloxane (001¯), and the edge sites (010), in aqueous NaCl at a concentration of 0.6 M to mimic seawater. Phosphate aggregation is enhanced by Na bridges, although at very high concentrations, the number of aggregates and the size of the largest cluster decrease. Calculated diffusion coefficients for both phosphate species drop sharply in hypersaline solutions, although the decay rate is higher for the HPO42− species. Diffusion results are in close agreement with experimental data. Phosphate adsorption on kaolinite occurs in clusters. The hydrophilic surface (001) adsorbs increasing amounts of each of the phosphate species as the salt concentration increases, more HPO42− than H2PO4−. The hydrophobic (001¯) surface remains non-reactive to any species. The hydrophilic (010) edge surface increases adsorption of H2PO4− and drastically decreases that of HPO42− as salt concentration increases. Bidentate adsorption of HPO42− on the much rougher edge surface, even if saturated with adsorbed Na ions, is sterically impeded. The dominant adsorption mechanism is through cationic bridges on the gibbsite surface and at the edges. The adsorption capacity of kaolinite, including all its surfaces, increases with salt concentration, reaching its highest value in synthetic seawater. The values are of the order, although lower than the experimental ones obtained with less-accessible clays with atomic substitutions. The use of clays to control phosphate content in coastal waters is expected to contribute to public health and sustainability of marine industrial activities.

Layers of Uranium Phosphate Nanorods and Nanoplates Encrusted on Fungus Cladosporium sp. Strain F1 Hyphae.

The hyphae of Cladosporium sp. strain F1 (CFGR 2020-301-00084) were heavily encrusted with pre-synthesized uranium phosphate minerals under a wide range of pH conditions. SEM and TEM images showed that nanorods and nanoplates of uranium phosphate minerals at pH 4 and 5 and at pH 6, 7, and 8, respectively, were tightly adsorbed along the hyphae of Cladosporium sp. strain F1, while only a few uranium phosphate minerals were observed on the hyphae of Aspergillus niger VKMF 1119. Based on the physical mobility and chemical stability of uranium phosphate minerals under in situ oxidizing environmental conditions, the application of Cladosporium sp. strain F1 has potential as a novel strategy for the remediation of uranium contamination in sediments and aquifers under a wide range of pH conditions where larger amounts of phosphate are present in the environment.

Study of struvite crystallization from fertilizer industry wastewater by using fluidized bed reactor

The fertilizer industry produces wastewater containing 9815 mg/L of phosphates and 2558 mg/L of ammonium, which may cause eutrophication if untreated. Wastewater that contains a large amount of phosphate can become a potential source of phosphate which is depleting on a global scale. Fluidized bed reactors are an effective method of phosphate recovery by producing struvite crystals. This study evaluates the effects of the upflow velocity on the performance of the fluidized bed and analyzes the struvite that is recovered. The experiment was conducted in laboratory scale at room temperature. Fertilizer industry wastewater and MgCl2 were added into fluidized bed reactors at 0.014, 0.019, and 0.0024 m/s upflow velocity. The operating pH was 8.5±0.2. Inside the reactors was sand No. 30/60 that worked as a seed material. The result showed that fluidized bed reactors could recover phosphate up to 73% and ammonium up to 57% at 0.014 m/s upflow velocity. Increasing the upflow velocity at intervals of 0.005 m/s could decrease the phosphate recovery by 1-2% and ammonium by 3-4%. SEM-EDX analysis showed that products were attached to the seed material, which contained N, P, Mg, O, Ca, F, and Si as the main constituent elements. The recovered products contain 60.2% of struvite, which mainly works as a slow released fertilizer.

Heavy metal leaching and distribution in glass products from the co-melting treatment of electroplating sludge and MSWI fly ash

Melting is a common solidification treatment that concentrates and encapsulates heavy metals into a glass matrix for waste containing heavy metals (Chae et al., 2016). To control the risk of heavy metal leaching into the glass product, a reduction in the amount of heavy metal was achieved in a pilot-scale furnace by co-melting electroplating sludge (EPS) and municipal solid waste incineration fly ash (MSWI FA). Through the melting process, the chloride from MSWI FA led to heavy metals volatilization in the form of chlorine salts. The fly ash additionally increased heavy metals volatilization by 4%–91%. The highest volatilization ratios of Zn, Pb, Cu, Cd, Cr and Ni were 33%, 96%, 33%, 79%, 81% and 31%, respectively. The concentrations of Pb and Zn in the secondary fly ash were close to the Pb and Zn concentrations in lead-zinc ore that are required in smelting industry. Moreover, glass sand was produced after the melting treatment. With an increase in the fly ash mixing ratio, the leaching concentration of Zn and Cu decreased to 3.8 mg/L and 2.1 mg/L. The leaching concentrations of other heavy metals stayed below 1 mg/L in all cases. When the ratio of MSWI FA reached 10%, the glass sand contained the least amount of impurities and a large amount of phosphate and silicate, which were probably responsible for the stability of the heavy metals. Therefore, our results provided a promising approach to the stability of the waste by the recovery of heavy metals in the co-treatment of heavy metal-bearing wastes.

Phosphate fertilizer impacts on glyphosate sorption by soil

This research examined the impact of field-aged phosphate and cadmium (Cd) concentrations, and fresh phosphate co-applications, on glyphosate sorption by soil. Soil samples were collected in 2013 from research plots that had received, from 2002 to 2009, annual applications of mono ammonium phosphate (MAP) at 20, 40 and 80 kg P ha−1 and from products containing 0.4, 70 or 210 mg Cd kg−1 as an impurity. A series of batch equilibrium experiments were carried out to quantify the glyphosate sorption distribution constant, Kd. Extractable Cd concentrations in soil had no significant effect on glyphosate sorption. Glyphosate Kd values significantly decreased with increasing Olsen-P concentrations in soil, regardless of the pH conditions studied. Experiments repeated with a commercially available glyphosate formulation showed statistically similar results as the experiments performed with analytical-grade glyphosate. Co-applications of MAP with glyphosate also reduced the available sorption sites to retain glyphosate, but less so when soils already contain large amounts of phosphate. Glyphosate Kd values in soils ranged from 173 to 939 L kg−1 under very strong to strongly acidic condition but the Kd was always <100 L kg−1 under moderately acidic to slightly alkaline conditions. The highest Olsen-P concentrations in soil reduced Kd values by 25–44% relative to control soils suggesting that, under moderately acidic to slightly alkaline conditions, glyphosate may become mobile by water in soils with high phosphate levels. Otherwise, glyphosate residues in agricultural soils are more likely to be transported off-site by wind and water-eroded sediments than by leaching or runoff.

Release of phosphate in a wetland by changes in hydrological regime

Phosphate can be removed from the water column in wetlands by adsorption, sedimentation, or biological uptake. However, phosphate removal efficiency in wetlands is variable because phosphate can also be re-released from wetland sediment to water body under certain conditions. This study was conducted to investigate mechanism of changes in removal efficiency of phosphate under different hydrological regime. For this, we constructed wetland microcosms, which were exposed to consecutive drying and rewetting periods. At the initial period of wetland operation, phosphate removal efficiency was high (60.1-100%) probably due to high adsorption capacity and low phosphatase activity. However, a large amount of phosphate was released in a rewetting period followed by a drying period. This result can be explained by two mechanisms. Firstly, rewetting of soil followed by drying released phosphate by desorption of previously adsorbed phosphate, which was clearly demonstrated in our supplementary isotherm experiment. Secondly, we observed a huge shift of phosphatase activity by drying of soil (1.4 nmol min(-1) g(-1) in the initial period and 12.4 nmol min(-1) g(-1) in a drying period), which lasted even in the rewetting period (14.2 nmol min(-1) g(-1)). These results suggest that repeated drying and rewetting events in wetlands can cause substantial release of phosphate by chemical changes and activation of P-mineralizing enzyme, which may last even when the water table is returned to the original level.

Type II Na+-Pi Cotransporters in Osteoblast Mineral Formation: Regulation by Inorganic Phosphate

During calcification of bone, large amounts of phosphate (P_i) must be transported from the circulation to the osteoid. Likely candidates for osteoblast P_i transport are the type II sodium-phosphate cotransporters NaPi-IIa and NaPi-IIb that facilitate transcellular P_i flux in kidney and intestine, respectively. We have therefore determined the cotransporters'' expression in osteoblast-like cells. We have also studied the cotransporters'' regulation by P_i and during mineralization in vitro. Phosphate uptake and cotransporter protein expression was investigated at early, late and mineralizing culture stages of mouse (MC3T3-E1) and rat (UMR-106) osteoblast-like cells. Both NaPi-IIa and NaPi-IIb were expressed by both osteoblast-like cell lines. NaPi-IIa was upregulated in both cell lines one week after confluency. After 7 days in 3mM P_i NaPi-IIa was strongly upregulated in both cell lines. NaPi-IIb expression was unaffected by both culture stage and P_i supplementation. The expression of both cotransporters was unaffected by P_i deprivation. In vitro mineralization at 1.5mM P_i was preceded by a three-fold increase in osteoblast sodium-dependent P_i uptake and a corresponding upregulation of both NaPi-IIa and NaPi-IIb. Their expression thus seem regulated by phosphate in a manner consistent with their playing a role in transcellular P_i flux during mineralization.

Binding of inorganic sulphate and phosphate in humid-climate soils measured using column leaching, equilibration and extraction methods

The ability of soil samples to bind applications of inorganic sulphate and phosphate was examined in the laboratory using column leaching, solution equilibration and extraction methods. Eleven soil samples from the Fraser Valley of British Columbia with a range of soil characteristics and management histories were examined. Column leaching trials showed that sulphate was bound to soils, but not as strongly as phosphate. There was no evidence of significant sulphate binding during the equilibration trials but there was substantial native sulphate bound by the soils as shown by extraction of significant sulphate concentrations by bicarbonate extraction following equilibration. This shows that sulphate is not bound according to the traditional theory of adsorption, but other undefined mechanisms are involved. Both column leaching and equilibration results showed that the samples studied varied considerably in their native phosphate retention attributes, with some samples releasing no phosphate and others releasing considerable phosphate into the water treatments. Equilibration trials showed that some of the soils bound large quantities of phosphate resulting in no phosphate in the soil solution whereas others bound much less resulting in significant phosphate concentrations in the soil solution. Phosphate binding followed the Freundlich equation in eight of the samples, the Tempkin equation in one sample and a direct linear relationship in two samples. The Langmuir equation fitted most of the samples that had followed Freundlich equation reasonably well, but did not fit the other samples. This showed that determination of the maximum amount of phosphate that can be bound by the sample (i.e., P saturation) using the Langmuir equation cannot be used for all humid-climate soils of British Columbia. Two alternate direct measurements are proposed to determine the potential risk of phosphate in soils to contaminate water: amount of phosphate released during equilibration with water (native unbound phosphate) and amount of phosphate bound during equilibration with a low (approximately 25 mg P kg-1) phosphate solution (potential for the soil to bind applied P). These results show that sulphate and phosphate binding mechanisms by coastal British Columbia soils are not well understood. The nature of the binding mechanisms needs to be determined to develop and interpret soil analyses for agronomic and environmental purposes. Key words: Sulphate binding, phosphate binding, P saturation, soil solution P

Hydration process and rheological properties of cement pastes modified by orthophosphate addition

The use of cement by nuclear industry for confining low radioactive waste knows a constant increase. The interest bore to this material is due to its mechanical and chemical properties. However, these properties may be modified by the nature and the amount of wastes introduced with the mixing solution especially with large amount of phosphate. Precipitation of hydroxylapatite in the cement paste at the very beginning after mixing was emphasized from a particular concentration of orthophosphate. It was also found that this phenomenon leads to an early rigidification of the cement paste. From a kinetics point of view, the evolution of hydration was both delayed and slowed down according to a pessimum of phosphate concentration. These results indicate a competition between a adsorption process of phosphate on the cement phases which delay the hydration of the cement pastes and a process of precipitation of hydroxylapatite which does not.

Water management of Lake Yogo targeting internal phosphorus loading

AbstractLake Yogo is a small, eutrophic lake located 1.3 km north of Lake Biwa, Japan. The lake, which was originally a natural, closed lake, has a unique water management system. It is replenished with water pumped from Lake Biwa and supplies irrigation water to ≈ 5 km2 of agricultural fields. As a result, Lake Yogo functions as a water storage dam and is artificially controlled. As seen in most stratified lakes in temperate regions, large amounts of phosphate (PO4) are released from the sediment in the hypolimnetic water layer during the summer stratification period. In order to reduce the impacts of internal phosphorus (P) loading, a destratification aeration system was installed in the lake. Although the stratification was weakened concomitant with a temperature increase in the hypolimnetic layers, anoxic conditions were still observed because of the small scale of the aeration system, with cyanobacterial blooms continuing to occur during the summer and autumn of every year. Although the internal P load at the autumn turnover is probably immediately scavenged by its incorporation into ferric oxyhydroxide colloids, the phytoplankton present at that time would doubtless benefit from the temporary, increased PO4 supply because of their rapid uptake rates. Although the PO4 transported continually from the hypolimnetic to the epilimnetic layers by the destratification aeration system should be scavenged as ferric oxyhydroxide colloids, a portion of the PO4 is probably incorporated into the phytoplankton biomass. As a result, an insufficient level of artificial destratification might support phytoplankton growth during the period of thermal stratification in the lake.

Bat guano and preservation of archaeological remains in cave sites

The formation of authigenic minerals in cave sediments can be used to reconstruct the paleochemical conditions that prevailed in the past, and in this way to assess the completeness of the archaeological record. Previous studies indicated that the major driving mechanisms for chemical diagenesis in prehistoric caves that result in the formation of authigenic minerals, are the degradation of bat guano and the local hydrology. We therefore investigated contemporary bat guano deposits in caves and the sediments directly below such deposits. The emerging patterns show that the formation of authigenic minerals occurs under acidic conditions within tens of years. The availability of phosphate, Al, K, and Fe increases with increasing organic matter degradation, while the availability of nitrogen and sulfur decreases. Insectivorous bat guano contains larger amounts of phosphate and is more acidic than fruit bat guano. In the first stages of diagenesis micro-chemical environments form within the degrading bat guano that result in the formation of a wide variety of authigenic minerals. During advanced stages of diagenesis steady state conditions are achieved resulting in authigenic mineral assemblages being dominated by one mineral type at the same locale. This is reminiscent of known distributions of authigenic minerals in prehistoric cave sediments. Under the acidic conditions produced by degrading bat guano deposits, calcareous artifacts and bones are not expected to persist for long periods of time, unless there is a lot of calcite in the sediments that could buffer the sediment water pH. Guano itself is not likely to be preserved. Periods of cave abandonment can be inferred from the presence of authigenic minerals in the sediments as it is during these times that bats mainly occupy the cave. The occurrence of certain authigenic minerals in open-air sites may serve as evidence for areas rich in organic matter containing phosphate (i.e., animal enclosures, latrines, sewers, trash pits) and/or bones. As the degradation process is rapid, the use of authigenic minerals to identify these loci is relevant to almost all archaeological, as well as historical sites.

Aminoacetone Induces Loss of Ferritin Ferroxidase and Iron Uptake Activities

Aminoacetone (AA) is a threonine and glycine metabolite overproduced and recently implicated as a contributing source of methylglyoxal (MG) in conditions of ketosis. Oxidation of AA to MG, NH4+, and H2O2 has been reported to be catalyzed by a copper-dependent semicarbazide sensitive amine oxidase (SSAO) as well as by copper- and iron ion-catalyzed reactions with oxygen. We previously demonstrated that AA-generated O2*-. and enoyl radical (AA*) induce dose-dependent Fe(II) release from horse spleen ferritin (HoSF); no reaction occurs under nitrogen. In the present study we further explored the mechanism of iron release and the effect of AA on the ferritin apoprotein. Iron chelators such as EDTA, ATP and citrate, and phosphate accelerated AA-promoted iron release from HoSF, which was faster in horse spleen isoferritins containing larger amounts of phosphate in the core. Incubation of apoferritin with AA (2.5-50 mM, after 6 h) changes the apoprotein electrophoretic behavior, suggesting a structural modification of the apoprotein by AA-generated ROS. Superoxide dismutase (SOD) was able to partially protect apoferritin from structural modification whereas catalase, ethanol, and mannitol were ineffective in protection. Incubation of apoferritin with AA (1-10 mM) produced a dose-dependent decrease in tryptophan fluorescence (13-30%, after 5 h), and a partial depletion of protein thiols (29% after 24 h). The AA promoted damage to apoferritin produced a 40% decrease in apoprotein ferroxidase activity and an 80% decrease in its iron uptake ability. The current findings of changes in ferritin and apoferritin may contribute to intracellular iron-induced oxidative stress during AA formation in ketosis and diabetes mellitus.

Production of benzaldehyde by encapsulated whole-cell benzoylformate decarboxylase

The whole cells of the microorganism were used as a source of intracellular enzyme without cell disintegration and complex purification of enzyme. Benzoylformate was converted to benzaldehyde using both free whole-cell enzyme (benzoylformate decarboxylase) from Pseudomonas putida cells and the whole-cell enzyme immobilized in a calcium alginate liquid-core capsule. Cells inoculated in calcium alginate capsules were cultured for 2 days in a medium containing a large amount of nitrogen sources and then cultured successively for 1 day in a new medium containing a large amount of phosphate. In a free whole-cell enzyme survey, benzaldehyde produced by the catalysis of whole-cell benzoylformate decarboxylase was consecutively converted to benzyl alcohol by benzyl alcohol dehydrogenase. Encapsulation of whole-cell enzymes gave a resistance of mass transfer in a capsule membrane which caused a lagging of appearance of benzaldehyde in the reaction medium. However, there was no production of benzyl alcohol, and benzaldehyde was produced ceaselessly even at the low initial concentration of benzoylformate until the reactant was consumed entirely. Encapsulated whole-cell enzyme from P. putida could be reused to produce benzaldehyde from benzoylformate without formation of benzyl alcohol, and retained 60% initial activity after 30 batches.

Uranyl precipitation by biomass from an enhanced biological phosphorus removal reactor.

Heavy metal and radionuclide contamination presents a significant environmental problem worldwide. Precipitation of heavy metals on membranes of cells that secrete phosphate has been shown to be an effective method of reducing the volume of these wastes, thus reducing the cost of disposal. A consortium of organisms, some of which secrete large quantities of phosphate, was enriched in a laboratory-scale sequencing batch reactor performing Enhanced Biological Phosphorus Removal, a treatment process widely used for removing phosphorus. Organisms collected after the aerobic phase of this process secreted phosphate and precipitated greater than 98% of the uranyl from a 1.5 mM uranyl nitrate solution when supplemented with an organic acid as a carbon source under anaerobic conditions. Transmission electron microscopy, energy dispersive x-ray spectroscopy, and fluorescence spectroscopy were used to identify the precipitate as membrane-associated uranyl phosphate, UO2HPO4.

Roles of phosphate and an enoyl radical in ferritin iron mobilization by 5-aminolevulinic acid

5-Aminolevulinic acid (ALA), a heme precursor that accumulates in acute intermittent porphyria (AIP) and lead poisoning, undergoes enolization and subsequent iron-catalyzed oxidation at neutral pH. Iron is released from horse spleen ferritin (HoSF) by both ALA-generated O 2 •− and enoyl radical (ALA ), which amplifies the chain of ALA oxidation (autocatalysis). Iron chelators such as EDTA, ATP, but not citrate, and phosphate accelerate this process and ALA-promoted iron release from HoSF is faster in horse spleen isoferritins containing larger amounts of phosphate in the core. ALA (+0.377 V versus standard hydrogen electrode) is less effective in releasing iron from ferritin than are thioglycollic acid, 6-hydroxydopamine, and N,N,N′,N′-tetramethyl- p-phenylenediamine. During electrochemical one electron oxidation of ALA in a nitrogen atmosphere, spin trapping experiments with 3,5-dibromo-4-nitrosobenzenesulfonic acid demonstrated the formation of a spin adduct characterized by a six line signal, indicating a secondary carbon-centered radical and attributed to a resonant ALA radical. Iron is also released in such anaerobic electrochemical oxidations of ALA in the presence of ferritin, suggesting that, in addition to O 2 •−, ALA can promote iron mobilization from ferritin. Hence, ALA may amplify the metal-catalyzed oxidation of ALA, damaging ALA-accumulating cells and possibly contributing to the symptoms of porphyria.

Behavior of Phosphate and Ammonium Ions in Forming and Melting Spherical Ice Crystals

Inclusion phenomena of phosphate and ammonium ions in ice crystals and the behavior of both ions dissolved from the melting ice crystals were investigated experimentally. The experiment was performed by forming spherical ice crystals from a solution containing phosphate and ammonium ions, and by melting them. At the formation of spherical ice crystals, large amounts of phosphate and ammonium ions were included near the center of the ice crystals. At melting, the concentration of both ions in the initially eluated solution was somewhat higher than in the solution eluated later. Some adsorption experiments for both ions on the surface of ice spheres were also performed in order to interpret the inclusion and dissolution behavior qualitatively.

Phosphate metabolism in red blood cells of critically ill neonates.

Very few data exist on phosphate metabolism in critically ill neonates. Therefore we studied the incidence of hypophosphataemia, the intracellular metabolism of phosphate by measuring adenosine 5'-triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG) in red blood cells, and excretion of phosphate in urine. The aims of the study were early detection of changes in phosphate metabolism as possible diagnostic markers of sepsis and defining the cause of hypophosphataemia.Neonates, treated in multidisciplinary paediatric intensive care unit (PICU), included in the study, were less than three days of age. Eighteen of them had respiratory distress syndrome (RDS) and 16 had microbiologically confirmed or clinical sepsis. The overall incidence of hypophosphataemia in critically ill neonates was over 80%, and was more common (88%) and more profound in those with sepsis than in those with RDS (79%). Therefore the septic neonates needed significantly larger amounts of phosphate to maintain normophosphataemia. In septic neonates ATP concentration in red blood cells was significantly lower than in neonates with RDS and controls, while the 2,3-DPG concentration was increased as a result of compensation. In septic neonates urinary losses of inorganic phosphate (Pi) were significantly higher than in neonates with RDS. Hypophosphataemia in critically ill neonates is at least partly due to higher urinary losses of phosphate.

Early Palaeolithic bone diagenesis in the Arago cave at Tautavel, France

Abstract Bones from level G in the Arago cave (Tautavel, Southern France, 450 ky) were analysed using a combination of particle induced X-ray and gamma-ray emission (PIXE and PIGME) and X-ray diffraction (XRD). Human occupation and guano production by bats introduced a large amount of phosphate into the cave and as a result a decarbonated pocket was formed in the sediment, characterized by the dissolution of clay minerals, calcite and bones, and by the precipitation of phosphate secondary minerals. The Al released by clay minerals was reprecipitated as crandallite in the few remaining bones, and as montgomeryite with traces of crandallite in the surrounding sediments. Bones within the pocket have very high levels of Al, Fe, F and Zn and often have ‘diffusive’ type U-shaped concentration profiles. These profiles show that post-mortem uptake of trace elements occurred, and thus that trace element composition has to be used with care in palaeonutritional studies but is indicative of local palaeoenvironment. This uptake is complicated by a large increase in hydroxylapatite crystallinity in Palaeolithic bones compared to modern or more recent ones, as a result of the large P influx which occurred in the Arago cave after the sediment deposition.

Simultaneous analysis of nitrate, nitrite, acetate and 3-hydroxybutyrate by HPLC

A HPLC-method for a simultaneous analysis of nitrate, nitrite, acetate and 3-hydroxybutyrate in a wide range of concentrations was developed. The paired ion chromatography is based on the method by H. Papen et al. [1]. The ranges of detectable concentrations were for nitrate and nitrite 0.05–300 mg/l, for acetate 10–1000 mg/l and for 3-hydroxybutyrate 10–2000 mg/l. The substances were detected with a dual wave UV-detector. Nitrate and nitrite were detected at two different wave-lengths (210 and 240 nm). Acetate and 3-hydroxybutyrate were detected at 210 nm. The method was not influenced by large amounts of phosphate, ammonium sulfate, magnesium sulfate and trace elements.