Phosphorus compounds in the dissolved and particulate phases in urban rivers and a downstream eutrophic lake as analyzed using 31P NMR

Phosphorus (P) discharges from human activities result in eutrophication of lakes. We investigated whether the forms of phosphorus (P) in rivers with high effluent loads flowing through urban areas of Sapporo, Japan, were transformed when transported downstream into a eutrophic lake, namely Lake Barato. We hypothesized that the inorganic P supplied from the rivers might be transformed to organic forms in the lake. The results showed that soluble reactive phosphorus (SRP) and particulate inorganic phosphorus (PIP) dominated in the river discharge to the lake. Suspended solids in the rivers were rich in iron (Fe) so PIP was associated with Fe. A comparison of the concentrations at the river mouth and 4.5 km downstream showed that the concentrations of SRP and PIP were lower at 4.5 km downstream than at the river mouth, whereas the concentrations of organic P (i.e., dissolved organic phosphorus and particulate organic phosphorus) were similar. The results from solution ³¹P nuclear magnetic resonance spectroscopy of lake water showed that pyrophosphate was only present in the particulate fraction, while orthophosphate diesters (DNA-P) were only present in the dissolved fraction. Riverine samples contained orthophosphate (ortho-P) only, while lake samples contained ortho-P, orthophosphate monoesters, and DNA-P. The results suggest that the P forms, particularly those of dissolved P, shifted from inorganic to organic forms as the water was discharged from the river to the lake.

Reactive and Additive Modifications of Styrenic Polymers with Phosphorus-Containing Compounds and Their Effects on Fire Retardance

Polystyrene, despite its high flammability, is widely used as a thermal insulation material for buildings, for food packaging, in electrical and automotive industries, etc. A number of modification routes have been explored to improve the fire retardance and boost the thermal stability of commercially important styrene-based polymeric products. The earlier strategies mostly involved the use of halogenated fire retardants. Nowadays, these compounds are considered to be persistent pollutants that are hazardous to public and environmental health. Many well-known halogen-based fire retardants, regardless of their chemical structures and modes of action, have been withdrawn from built environments in the European Union, USA, and Canada. This had triggered a growing research interest in, and an industrial demand for, halogen-free alternatives, which not only will reduce the flammability but also address toxicity and bioaccumulation issues. Among the possible options, phosphorus-containing compounds have received greater attention due to their excellent fire-retarding efficiencies and environmentally friendly attributes. Numerous reports were also published on reactive and additive modifications of polystyrene in different forms, particularly in the last decade; hence, the current article aims to provide a critical review of these publications. The authors mainly intend to focus on the chemistries of phosphorous compounds, with the P atom being in different chemical environments, used either as reactive, or additive, fire retardants in styrene-based materials. The chemical pathways and possible mechanisms behind the fire retardance are discussed in this review.

Dermal exposure to plasticizers in nail polishes: An alternative major exposure pathway of phosphorus-based compounds

Phosphorus-based compounds are used as plasticizers in the manufacture of many products found in the indoor environment. Here we quantitatively investigated dermal exposure to phosphorus-based compounds contained in 45 nail polishes purchased in Japan. The alternative plasticizer triphenyl phosphate (TPhP) was detected in some samples of the nail polishes made in the USA (concentration, 1.1-1.8 wt%). The potential dermal exposure rates for TPhP, estimated using ConsExpo (version 5.0; Dutch National Institute for Public Health and the Environment), were in the range 200 (5%ile)-1700 (50%ile)-5000 (95%ile) ng kg-bw^-1 day^-1, which is more than 1400 times the reported values for exposure via dust ingestion and inhalation. Thus, dermal exposure via nail polish may be a major route of exposure to TPhP. The margin of exposure range for TPhP was 3.6 × 10⁵-4.1 × 10⁴-1.4 × 10⁴. For comparison, the potential dermal exposure rate range for the conventional plasticizer dibutyl phthalate and the alternative plasticizer acetyl tributyl citrate was 360-3500-14,000 and 430-4100-17,000 ng kg-bw^-1 day^-1, respectively, and the margin of exposure range was 4.1 × 10³-4.2 × 10²-1.1 × 10² and 2.3 × 10⁵-2.4 × 10⁴-5.9 × 10³, respectively.

Characterization of phosphorus forms in a Eutrophic Lake, China

In this study, molecular compositions of cyanobacteria, suspended matter, and surface sediments in the Dianchi Lake, a highly eutrophic lake, were investigated by solution and solid-state ³¹P nuclear magnetic resonance (NMR) spectroscopy. A solution-state ³¹P NMR spectral analysis of NaOH-EDTA-extracted samples revealed the presence of orthophosphate (ortho-P, 48.5%-91.2% of the total extracted phosphate), orthophosphate monoester (mono-P, 7.3%-43.9%), orthophosphate diester (diester-P, 0.9%-3.9%), and pyrophosphate (pyro-P, 0.7%-5.5%). The organic phosphorus (Po) distribution in suspended matters and cyanobacteria was relatively similar but different from surface sediments. The inorganic phosphorus (Pi) distribution in suspended matters and surface sediments was slightly similar. Results of the solid-state ³¹P NMR spectral analysis of non-extractable residue showed that cyanobacteria and suspended matter contain a large proportion of Po and poly-P. For surface sediment, only metal-bonded pyro-P and a high proportion of ortho-P were detected. The solid-state ³¹P NMR spectra results of extracted residual indicated that several of the pyro-P bound to metals and other Pi or Po compounds associated with mineral phases in suspended matter and surface sediment are non-extractable. This result revealed that a high proportion of biogenic phosphorus is bioavailable. These results verify the process of biogenic poly-P regeneration in the Dianchi Lake given that Po, poly-P, and pyro-P are predominant in cyanobacteria and can be released into lake water through chemical and biological degradation, thus further worsening eutrophication.

Internal phosphorus loading across a cascade of three eutrophic basins: A synthesis of short- and long-term studies

Ascertaining the phosphorus (P) release processes in polymictic lakes is one of the methodologically most complex questions in limnology. In the current study, we combined short- and long-term investigations to elucidate the role of sediments in the P budget in a chain of eutrophic lake basins. We quantified the internal loading of P in three basins of Lake Peipsi (Estonia/Russia) for two periods characterized by different external P loadings using radiometrically dated sediment cores (long-term studies). The relationships between different water quality variables and the internal P loading, and the external P loading were studied. Our short-term studies aimed at elucidating the possible mechanisms behind variations in internal P loading included examination of the surficial sediments, i.e., seasonal measurements of redox potential, sediment pore water P concentrations and diffusive fluxes. Our results provided evidence for a potentially high importance of internal P loading in regulating water quality. The sediment core analyses revealed an increase in the internal P loading during the period of lower external P loading coinciding with the general deterioration in the lake water quality (i.e, higher concentrations of soluble reactive phosphorus, total phosphorus and biomass of cyanobacteria). Increase in wave action between the two studied periods appeared to cause more frequent sediment resuspension, and thus be the most likely reason for the variations in internal P loading. Our short-term measurements indicated that resuspension events can be followed by a considerable increase in the diffusive fluxes.

Dynamics of particulate phosphorus in a shallow eutrophic lake

We tested the hypothesis that in shallow, eutrophic Lake Kasumigaura, the concentration of particulate phosphorus (PP) is controlled by biogenic P (P in living or dead phytoplankton and bacterial cells), rather than by resuspension of inorganic P in sediment. Increases in wind velocity and turbidity were associated with bottom shear stress exceeding the critical value for the lake (τc=0.15Nm(-2)); this increased turbidity was due to sediment resuspension. However, concentrations of PP; HCl-extractable, reactive P in PP (P-rP); and HCl-extractable, non-reactive P in PP (P-nrP) were not correlated with wind velocity (PP vs. wind velocity: r=0.40, p>0.05). Rather, the P-nrP concentration accounted for approximately 79% of PP, and the concentrations of PP, P-rP, and P-nrP were correlated with the particulate organic carbon (POC) concentration (POC vs. PP: r=0.90, p<0.01; POC vs. P-rP: r=0.82, p<0.01; POC vs. P-nrP: r=0.86, p<0.01). In our (31)P nuclear magnetic resonance spectroscopy results, mononucleotides accounted for the largest proportion among the detected P compound classes. In addition, concentrations of mononucleotides, orthophosphate, and pyrophosphate were significantly higher in samples with high POC concentrations, whereas the DNA-P concentration was not. These results suggest that biogenic P affects PP concentrations more strongly than does sediment resuspension, and the production of biogenic P creates a pool of mononucleotides, a class of easily degradable P, even in shallow, eutrophic Lake Kasumigaura.

Determination of Phosphorus and Potassium in Commercial Inorganic Fertilizers by Inductively Coupled Plasma-Optical Emission Spectrometry: Single-Laboratory Validation, First Action 2015.18

A previously validated method for the determination of both citrate-EDTA-soluble P and K and acid-soluble P and K in commercial inorganic fertilizers by inductively coupled plasma-optical emission spectrometry was submitted to the expert review panel (ERP) for fertilizers for consideration of First Action Official Method(SM) status. The ERP evaluated the single-laboratory validation results and recommended the method for First Action Official Method status and provided recommendations for achieving Final Action. Validation materials ranging from 4.4 to 52.4% P2O5 (1.7-22.7% P) and 3-62% K2O (2.5-51.1% K) were used for the validation. Recoveries from validation materials for citrate-soluble P and K ranged from 99.3 to 124.9% P and from 98.4 to 100.7% K. Recoveries from validation materials for acid-soluble "total" P and K ranged from 95.53 to 99.40% P and from 98.36 to 107.28% K. Values of r for citrate-soluble P and K, expressed as RSD, ranged from 0.28 to 1.30% for P and from 0.41 to 1.52% for K. Values of r for total P and K, expressed as RSD, ranged from 0.71 to 1.13% for P and from 0.39 to 1.18% for K. Based on the validation data, the ERP recommended the method (with alternatives for the citrate-soluble and the acid-soluble extractions) for First Action Official Method status and provided recommendations for achieving Final Action status.

Phosphorous fractionation in mangrove sediments of Kerala, south west coast of India: the relative importance of inorganic and organic phosphorous fractions

The study of phosphorous dynamics in mangrove ecosystems of the northern Kerala coast aims to delineate its relationships with other biogeochemical parameters. Our intension is to check the validity of the hypothesis that these mangrove ecosystems act as an efficient trap of organic phosphorous by acting as P sink. The dissolved inorganic phosphate displayed higher concentration in monsoon that could be correlated with higher P leaching from mangrove litter as well as terrigenous input during wet season. Fe(OOH)≈P was much higher in monsoon (235.23 to 557.70 μg g(-1)) and lower in pre-monsoon (36.50 to 154.97 μg g(-1)), and displayed significant contribution towards the inorganic sedimentary P fractions. In monsoon, adsorption of P on iron hydroxides is enhanced by fresh water conditions, but pre-monsoon is characterised by the reductive dissolution of iron oxy hydroxides and the subsequent efflux of P to water column. CaCO3≈Pinorg may be present as an inert fraction in the sediment matrix, and did not display any interrelationship with other geochemical parameters. The abundant total organic P (25 to 73 %) fractions, largely derived from P bound with humic/fulvic acid, played a major role in immobilising P and regulating its dynamics in the nearby estuarine and coastal environment.

Preliminary investigation on the potential use of two C4 turfgrass species to reduce nutrient release in a Mediterranean drained peatland

This study compared dry matter production, nutrient uptake and tissue nutrient concentration of two C4 turfgrass species (Cynodon dactylon × Cynodon transvaalensis Burtt Davy and Paspalum vaginatum Swartz) supplied with three different nutrient solutions in a sand and peat culture. The 8-week experiment was performed in mesocosms and simulated the conditions of an open-field phyto-treatment system located in a Mediterranean drained peatland (Tuscany, Italy). Peat was collected on the site, and one of the solutions mimicked drainage water flowing into it. Three hypotheses were tested: (i) the species chosen efficiently removed nutrients from both the solution and the substrate; (ii) peat contributed to the nutrient load; and (iii) the species chosen were suitable in the open-field system. Both species adapted well to the experimental conditions and demonstrated considerable ability to remove nutrients. P. vaginatum took up nitrogen more efficiently, mainly in conditions of high nutrient availability. We observed supplementary nutrient uptake by plants in the peat treatment. Performances of the two C4 turfgrasses extrapolated to the field scale seemed effective from a phyto-treatment perspective.

The phosphorus speciations in the sediments up- and down-stream of cascade dams along the middle Lancang River

We detected the longitudinal variability of phosphorus speciations and its relation to metals and grain size distribution of sediments in three cascade canyon reservoirs (Xiaowan, Manwan and Dachaoshan) along Lancang River, China. Five phosphorus speciations including loosely bound P (ex-P), reductant soluble P (BD-P), metal oxide-bound P (NaOH-P) calcium-bound P (HCl-P) and residual-P were extracted and quantified. Results showed that in Manwan Reservoir HCl-P accounted for the largest part of total phosphorus (TP) (49.69%), while in Xiaowan and Dachaoshan reservoirs, NaOH-P was the most abundant speciation which accounted for 57.21% and 55.19% of total phosphorus respectively. Higher contents of bio-available phosphorus in Xiaowan and Dachaoshan reservoirs suggested a high rate of P releasing from sediments. Results also showed ex-P and HCl-P had positive correlation with Ca. Total phosphorus was positively correlated with Fe. The silt/clay contents of the sediments had close relationship with ex-P (r=0.413, p<0.05), NaOH-P (r=0.428, p<0.05) and BAP (r=0.458, p<0.05). The concentration of Ca, Mn and silt/clay speciation in the sediments explained 40%, 10% and 4% of the spatial variation of phosphorus speciations, respectively.

Nitrogen and phosphorus distribution in a constructed wetland fed with treated swine slurry from an anaerobic lagoon

Nitrogen and phosphorus distribution in a constructed wetland fed with treated swine slurry from an anaerobic lagoon were studied. The methodology considered a daily meteorological monitoring site. During 2011 to 2012, water, soil and plants (Schoenoplectus californicus (C.A. Méyer) Sójak, Typha angustifolia (L.)) were seasonally sampled (spring and fall) into the constructed wetland. During study period, results showed that rainfall was the main factor of maintenance hydraulic conditions, while evapotranspiration was driver of variations in water storage level. Nitrogen and phosphorus removal from the water phase were up to 54% and 37%, respectively. Onto soil were adsorbed over 70% nitrogen and 65% phosphorus. Phosphorus was less mobile than nitrogen, since it was bound to oxides Fe-Mn. Inorganic nitrogen species were affected by level water and seasonal vegetable maturation. During spring, N-NH4(+) was the predominant soil species, while in the fall, N-NO3(-) was dominant near the belowground part of Sc and NH4(+) near to the belowground zone of Ta. In addition, nutrients uptake was less than 30% with 64% aboveground-spring and 85% belowground-fall for both plants. Findings showed nitrification process evidences when water levels are below 0.1 m.

[Characteristics of phosphorus fractions in sediments of constructed wetlands]

In order to better understand phosphorus (P) cycle in wetland ecosystem, the characteristics of phosphorus fractions in sediments of Heituwa constructed wetland system were investigated using soil organic phosphorus (Po) fractionation scheme and 31P-NMR technology. The concentrations of TP, Pi, Po and soil organic matter were all increased along the flow direction. Four kinds of P-compounds (orthophosphate, orthophosphate monoesters, orthophosphate diesters, and pyrophosphate) were detected in the NMR spectrum. Orthophosphate and phosphate monoester accounted for the dominants position in sediment phosphorus. This study indicates that the Po in sediment plays an importance role in wetland ecosystem and suggested that more attention should be paid to Po, especially to DNA-P and pyrophosphate in further research and management of constructed wetlands. Compared with the traditional chemical analysis method, 31P-NMR method has sample preparation relatively simple and is less destructive, with components analyzed completely. Using 31P-NMR technology, the cognition of wetland phosphorus cycle, especially organophosphate, will be expected to get new breakthrough.

Geochemical characteristics of phosphorus in surface sediments of two major Chinese mariculture areas: the Laizhou Bay and the coastal waters of the Zhangzi Island

Phosphorus (P) in surface sediments of the Laizhou Bay (LB) and the coastal waters around the Zhangzi Island (ZI) was analyzed. Six forms of P were separated - exchangeable or loosely sorbed P (Ads-P), aluminum-bound P (Al-P), iron-bound P (Fe-P), authigenic apatite plus CaCO3-bound P plus biogenic apatite (Ca-P), detrital apatite plus other inorganic P (De-P) and organic P (OP). The average contents of P in the LB were in the order: De-P>OP>Ca-P>Fe-P>Ads-P>Al-P; in the ZI, the corresponding order was De-P>OP>Fe-P>Ca-P>Ads-P>Al-P. Due to the high nutrient loadings from the surrounding rivers, TP contents in sediments of the LB were higher than in those of the ZI. The potential bio-available P (Ads-P and OP) accounted for 14.7% and 24.2% of TP in sediments of the LB and the ZI, respectively.

Phosphorus-31 nuclear magnetic resonance assignments of biogenic phosphorus compounds in sediment of an artificial Fuyangxin River, China

River eutrophication could drastically influence the phosphorus (P) in the water and sediment. To understand the biogenic-P species, distribution and bioconversion, five sediment samples were collected from an artificial river, and analyzed by phosphorus-31 nuclear magnetic resonance ((31)P-NMR). The P pollution in the water and sediment were both severe. The average concentrations of total P (TP) and solution reactive phosphorus in the water were 3.0 and 2.6 mg L(-1), respectively, which surpass grade V of the national quality standard (China) and should not be used for any purpose. The river sediments accumulated significant inorganic phosphorus (Pi) and organic phosphorus (Po); in the P fractionation, the rank order of the P fractions was as follows: Ca-P > NaOH-Pi > Res-P > KCl-P > NaOH-Po, with average relative proportions of 25.1:16.8:6.6:1.7:1:0. Six P compounds were detected in the NaOH-EDTA extract by (31)P-NMR. Mono-P (8.96-29.58 %) was the dominant forms of biogenic-P, and other smaller fractions of biogenic-P were also observed, including pyro-P (0.22-0.86 %), DNA-P (0.75-2.03 %), phon-P (0-1.57 %), and lipids-P (0-2.66 %). The TP and biogenic-P decreased along the direction of flows, with their average relative proportions 7.97:1.20:1.49:1.00:1.00 and 40.87:2.34:3.46:1.60:1 from the upstream to downstream, respectively. The concentration and species of Po in NaOH-Po were lower than found in (31)P-NMR analysis in this research. Thus, the use of 0.25 M NaOH and 50 mM EDTA extracts and solution (31)P-NMR analysis was a more accurate method for quantifying biogenic-P in the river sediments than P fractionation.

Occurrence of surfactants in wastewater: hourly and seasonal variations in urban and industrial wastewaters from Seville (Southern Spain)

Surfactants are daily discharged to the environment from urban and industrial activities. The assessment of the risk derived from the presence of these compounds in the environment requires a deep knowledge about their sources and their distribution in wastewater treatment plants (WWTPs). However, in spite of several studies reporting their presence in WWTPs, only a small number is focused on their different sources. In this work, the distribution of anionic (linear alkylbenzene sulfonates) and non-ionic (nonylphenol ethoxylates) surfactants in WWTPs and in urban and industrial wastewater collection systems has been investigated. Seasonal and daily variability was also assessed. Concentrations of linear alkylbenzene sulfonates in influent and effluent wastewaters ranged from 1155 to 9200 μg L(-1), and from below limit of detection to 770 μg L(-1), respectively, whereas the concentrations of nonylphenol ethoxylates were significantly lower. Linear alkylbenzene sulfonates were efficiently removed (>96%), while mean removal rates of nonylphenol ethoxylates were significantly lower (<20%). Studies carried out in different seasons revealed seasonal discharge patterns from both urban and industrial activities. The analysis of wastewater collection systems showed a major contribution of linear alkylbenzene sulfonates from urban areas while, in the case of nonylphenol ethoxylates, their major contribution came from industrial activities. In all cases the discharge patterns of surfactants were related with the water consumption.

Utilisation of gas-phase ion-molecule reactions for differentiation between phospho- and sulfocarbohydrates

Gas-phase ion-molecule reactions of four boron-containing neutrals were explored as a means for differentiation between isobaric phospho- and sulfocarbohydrates. Phosphorylation and sulfation impose an addition of 80 Da to the molecular mass, so for low-resolution mass spectrometers compounds that have such modifications will appear at the same nominal mass-to-charge (m/z) ratio. However, the ions of these isobaric species behave differently in ion-molecule reactions. All four evaluated neutral molecules [trimethyl borate (TMB), triethyl borate (TEB), diethylmethoxyborane (DEMB) and diisopropoxymethylborane (DIPMB)] proved to be reactive towards phosphorylated sugars and unreactive towards sulfated carbohydrates. In addition, TMB and TEB were found suitable for distinguishing positional isomers of phosphorylated carbohydrates, while reactions with DEMB and DIPMB were successful in differentiating phosphorylated, sulfated and unmodified deprotonated sugars. Similar reactions in the positive ion mode (alkali cationised) were found to be less conclusive.

Durability of changes in phosphorus compounds in water of an urban lake after application of two reclamation methods

The study was conducted on Długie Lake (area 26.8 ha, maximum depth 17.3 m), located in the town of Olsztyn, in north-eastern Poland (the Masurian Lake District). For 20 years starting in the 1950s, Długie Lake was used as a receiver of raw domestic and storm sewage in quantities oscillating between 350 and 400 m(3) day(-1). This led to complete degradation of the lake, known as saprotrophy. After some preliminary protective treatments in the catchment, the lake has been renewed by artificial aeration with thermal destratification and the phosphorus inactivation methods. Long-term reclamation of the reservoir has resulted in distinct and durable improvement of water quality. Before the restoration, the average phosphorus concentration in the surface water layer was 0.079 mg P L(-1) and in the over-bottom water it reached 2.277 mg P L(-1). The total phosphorus (TP) level also was very high, i.e. up to 3.5 mg P L(-1). After the restoration, these values have declined to 0.001-0.017 mg P L(-1) in the case of mineral P, and the current TP concentrations do not exceed 0.350 mg P L(-1).

Phosphorus-containing fluorinated organics: polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluorophosphonates (PFPAs), and perfluorophosphinates (PFPIAs) in residential indoor dust

Indoor dust is thought to be a source of human exposure to perfluorocarboxylates (PFCAs) and perfluorosulfonates (PFSAs), but exposures to emerging organofluorine compounds, including precursors to PFCAs and PFSAs via indoor dust, remain unknown. We report an analytical method for measuring several groups of emerging phosphorus-containing fluorinated compounds, including polyfluoroalkyl phosphoric acid diesters (diPAP), perfluorophosphonates (PFPA), and perfluorophosphinates (PFPIA), as well as perfluoroethylcyclohexane sulfonate (PFECHS) in indoor dust. This method was used to analyze diPAP, PFPA, and PFPIA levels in 102 residential dust samples collected in 2007-2008 from Vancouver, Canada. The results indicated a predominant and ubiquitous presence of diPAPs (frequency of detection 100%, mean and median ΣdiPAPs 7637 and 2215 ng/g). Previously measured median concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and fluorotelomer alcohols (FTOHs) in the same samples were 14-74 times lower than ΣdiPAP levels, i.e. 71 ng/g PFOS, 30 ng/g PFOA, and 152 ng/g ΣFTOHs. PFPAs and PFPIAs were detected in 62% and 85% of samples, respectively, at concentrations nearly 3 orders of magnitude lower than diPAPs (median 2.3 ng/g ΣPFPAs and 2.3 ng/g ΣPFPIAs). PFECHS was detected in only 8% of dust samples. To the best of our knowledge, this is the first report of these compounds in indoor dust. In this study, diPAP concentrations represented 98% ± 7% of the total measured analytes in the dust samples. Detection of diPAPs at such high concentrations in indoor dust may represent an important and as-yet unrecognized indirect source of PFCA exposure in humans, given the identified biotransformation pathways. Identifying the sources of diPAPs to the indoor environment is a priority for future research to improve air quality in households.

Ferrous iron phosphorus in sediments: development of a quantification method through 2,2'-bipyridine extraction

The role of ferrous iron in the phosphorus cycle of an aquatic ecosystem is poorly understood because of a lack of suitable methods to quantitatively evaluate ferrous iron phosphorus (FIP) phases. Using sediments sampled from Fubao Bay of Dianchi Lake in China, a novel extraction method for FIP using 2,2'-bipyridine was explored. Total phosphorus and iron in the sediments ranged from 1.0 to 5.0 mg/g (dry weight) and 28.5 to 90.6 mg/g, respectively. Organic content (as indicated by loss on ignition or LOI) and iron(II) ranged from 3.1 to 27.0% and 26.5 to 64.9 mg/g, respectively. The dissolution dynamics of FIP extraction with a low solid/liquid ratio (1:25) indicated that a single application of 0.2% 2,2'-bipyridine extracted both iron(II) (Fe(II)) and phosphorus (as PO4(3-)) in sediments with different organic contents with low efficiency. The extraction efficiency of Fe(II) was improved by alteration of the solid/liquid ratio, but the effect was limited. However, addition of a 1:1000 solid/liquid ratio of 0.5 M potassium chloride to a 0.2% 2,2'-bipyridine solution significantly accelerated extraction of FIP with the release of Fe(II) and phosphorus toward equilibrium at approximately 150 hours. Further investigation demonstrated that 2,2'-bipyridine exhibited a higher selectivity in distinguishing FIP from phosphorus bound to ferric (Fe(III)) oxides or precipitated by calcium (Ca2+). Air-drying sediments significantly decreased the amount of extracted FIP, which indicates that fresh, wet sediment should be used in this type of FIP extraction. Based on experimental results using the proposed extraction protocol, (1) FIP in sediments of Fubao Bay had a predominant status in the lake sediment and accounted for 23.4 to 39.8% of total phosphorus, and (2) Fe(II)(FIP) released in the extraction is directly proportional to phosphorus(FIP) (Fe(II)(FIP) = 2.84 x P(FIP) + 0.0007; R2 = 0.97) with an average molar ratio of Fe(II)(FIP)/P(FIP) of 2.7. This study shows that FIP extraction with 2,2'-bipyridine is a robust method for releasing ferrous iron associated with phosphorus. Further, the high percentage of FIP in total phosphorus (40%) measured in the study site using this extraction method suggests that FIP might have been often underestimated in previous studies.

Biogenic phosphorus compounds in sediment and suspended particles in a shallow eutrophic lake: a ³¹P-nuclear magnetic resonance (³¹P NMR) study

Differences in biogenic phosphorus (P) compounds between sediment and suspended particles in aquatic environments are important for understanding the mechanisms of internal P loading, but these differences are still unknown. We used solution-state (31)P-nuclear magnetic resonance spectroscopy ((31)P NMR) with NaOH-ethylenediaminetetraacetic extraction to detect the multiple P compounds in suspended particles and sediment in the eutrophic Lake Kasumigaura, including orthophosphate monoesters, orthophosphate diesters, pyrophosphate, and polyphosphate. We tested the hypothesis that there is a significant difference between these groups in suspended particles and sediment. Biogenic P other than orthophosphate was found in significantly higher proportions in suspended particles (74.3% of total P) than in sediment (25.6%). Orthophosphate monoesters were comparatively more abundant in suspended particles, as indicated by the ratio of orthophosphate diesters to monoesters (average, 0.31 for suspended particles; 1.05 for sediment). The compounds identified as orthophosphate monoesters by (31)P NMR spectroscopy originated mainly from phospholipids (α-glycerophosphate and β-glycerophosphate) and ribonucleic acid (RNA-P), whereas the orthophosphate diesters included mostly DNA (DNA-P). These results suggest that the dynamics of orthophosphate diesters, the production of DNA-P, or the degradation of phospholipids, play an important role in P cycling in Lake Kasumigaura.

[Forms and distributions of particulate phosphorus in the surface sediments of North Yellow Sea]

Surface sediments were collected from the North Yellow Sea in October 2007. The sediments were analyzed with modified SEDEX to obtain six forms of phosphorus. The results indicate that among the total phosphorus the detrital phosphorus and authigenic phosphorus are the main forms and the content varies from 25.7 to 122.5 microg x g(-1) and from 5.7 to 176.2 microg x g(-1), respectively, which taking up 17.0% -56.9% and 10.2% -49.8% of the total phosphorus. The content of exchangeable phosphorus, extractable organic phosphorus, iron-bound phosphorus and refractory phosphorus ranges from 5.5 to 43.9, from 4.1 to 41.4, from 2.3 to 26.7, from 6.0 to 33.6 microg x g(-1), respectively. Detrital and authigenic phosphorus are the major forms of the total phosphorus, indicating that the natural input is the major source of particle phosphorus in the study area. The content of iron-bound phosphorus is low, indicating that human input is minor in the area; mass fraction of the extractable organic phosphorus and refractory organic phosphorus is low, indicating that there is a low organic content while the main form of the total phosphorus is inorganic in the surface sediments of this area. Bioavailable phosphorus as exchangeable phosphorus, extractable organic phosphorus and iron-bound phosphorus account for 6.7% - 33.2% of the total particle phosphorus, indicating that bioavailability of phosphorus in the surface sediments is low.

Phosphorus flow and characterization in dry-grind corn ethanol plants

Both the high phosphorus (P) content and P bioavailability of the animal feed coproducts of the corn-ethanol industry could potentially contribute to increased manure and soil P levels and associated environmental issues (e.g., eutrophication). Therefore, a detailed modeling of total P mass flow to the coproducts (i.e., dry distillers grains with solubles, DDGS) was performed. Distribution of P between inorganic P and phytase-hydrolyzable P forms was quantified for selected coproducts (thin stillage, DDGS, modified DDGS [mDDGS]). The P mass balance indicated that although corn is the major P contributor to the coproducts (80.2%), a substantial portion (19.4%) comes from yeast addition. Of the two components constituting DDGS, wet distillers grains and condensed solubles, the latter contributes to only one-third of the mass but, importantly, yields 70.9% of P. The phytase enzyme used, , was very effective in hydrolyzing the nonorthophosphate P components of thin stillage, DDGS and mDDGS. Our results would help track P movement during various dry-grind processing steps and formulate strategies for phytase enzyme supplementation to various postfermentation coproducts from corn-ethanol plants.

Blooming of Microcystis aeruginosa in the reservoir of the reclaimed land and discharge of microcystins to Isahaya Bay (Japan)

PURPOSE

In the reservoir created in the reclaimed land in Isahaya Bay, Japan, Microcystis aeruginosa, which produces microcystins (MCs), bloomed every year, and the water with high levels of MCs in the reservoir has been often drained to Isahaya Bay to adjust the water level. The principal aims of this study are to clarify the water conditions suitable for blooming of M. aeruginosa in the reservoir, to follow the amount of distribution of MCs inside and outside the reservoir, and to discuss how blooming of M. aeruginosa is controlled in the reservoir and how MCs produced by Microcystis spread or accumulate in the aquatic environment.

METHOD

We monitored the water quality (temperature, salinity, dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus) in the reservoir with seasonal blooming of microalgae including phytoplankton and M. aeruginosa using the concentrations of chlorophyll α and MCs, respectively, and collected the surface sediment in the reservoir and the bay to determine the MC content using the ELISA method.

RESULT

M. aeruginosa bloomed in extremely low DIN conditions of the water in warm seasons (spring and late summer to autumn). The year-mean standing stock of MCs was approximately 34.5 kg in the water and 8.4 kg in the surface sediment in the reservoir. Approximately 64.5 kg of MCs was discharged with the effluent to the bay in a year.

CONCLUSION

Since a large amount of MCs always suspends in the water in the reservoir and it has been discharged to the bay, suspension-feeding animals are exposed most seriously to the high levels of MCs occurring in these areas. We need to pay attention to the danger of widespread dispersal of MCs and biological concentration of MCs by fish and clam inside and outside the reservoir.

Evaluation of the giant reed (Arundo donax) in horizontal subsurface flow wetlands for the treatment of dairy processing factory wastewater

Two emergent macrophytes, Arundo donax and Phragmites australis, were established in experimental horizontal subsurface flow (HSSF), gravel-based constructed wetlands (CWs) and challenged by treated dairy processing factory wastewater with a median electrical conductivity of 8.9 mS cm(-1). The hydraulic loading rate was tested at 3.75 cm day(-1). In general, the plants grew well during the 7-month study period, with no obvious signs of salt stress. The major water quality parameters monitored (biological oxygen demand (BOD), suspended solids (SS) and total nitrogen (TN) but not total phosphorus) were generally improved after the effluent had passed through the CWs. There was no significance different in removal efficiencies between the planted beds and unplanted gravel beds (p > 0.007), nor was there any significant difference in removal efficiencies between the A. donax and P. australis beds for most parameters. BOD, SS and TN removal in the A. donax and P. australis CWs was 69, 95 and 26 % and 62, 97 and 26 %, respectively. Bacterial removal was observed but only to levels that would allow reuse of the effluent for use on non-food crops under Victorian state regulations. As expected, the A. donax CWs produced considerably more biomass (37 ± 7.2 kg wet weight) than the P. australis CWs (11 ± 1.4 kg wet weight). This standing crop equates to approximately 179 and 68 tonnes ha(-1) year(-1) biomass (dry weight) for A. donax and P. australis, respectively (assuming a 250-day growing season and single-cut harvest). The performance similarity of the A. donax and P. australis planted CWs indicates that either may be used in HSSF wetlands treating dairy factory wastewater, although the planting of A. donax provides additional opportunities for secondary income streams through utilisation of the biomass produced.

Research and application of in-situ control technology for sediment rehabilitation in eutrophic water bodies

Phosphorus (P) is often the limiting nutrient for algal growth, and P in sediments can be released under suitable conditions. To control P release, in-situ control technology with lanthanum (La) modified bentonite clay (Phoslock(®)) was proposed and its effectiveness was tested and evaluated both in laboratory and field trials. The results of static and dynamic simulation experiments under different environmental conditions showed that with the application rate of Phoslock(®) at 0.5 kg/m(2), the orthophosphate (PO(4)-P) concentration of the overlying water decreased to a low level (≤0.02 mg/L) within 10 days. Even under anaerobic and high pH (pH = 9.0) conditions, the phosphate release suppression efficiency reached 98.3%, and the P-release rate was -8.20 mg/m(2) d (negative value indicates P adsorption by Phoslock(®)). The monitoring data of the field sediments rehabilitation project were consistent with the results achieved in laboratory experiments, thus showing that the application of Phoslock(®) could inhibit the internal P release effectively.

Observations of nitrogen and phosphorus biogeochemistry in a surface flow constructed wetland

Free surface water constructed wetlands (CWs) provide a buffer between domestic wastewater treatment plants and natural waterways. Understanding the biogeochemical processes in CWs is crucial to improve their performance. In this study we measured a range of water and sediment parameters, and biogeochemical processes, in an effort to describe the processing of nutrients within two wetland cells in series. As a whole the studied CW effectively absorbed both nitrogen (N) and phosphorus (P) emanating from the waste treatment plant. However the two individual cells showed marked differences related to the availability of oxygen within the water column and the sediments. In one cell we speculated that the prevalence of surface plant species reduced its ability to function as a net nutrient sink. Here we observed a build-up of sediment organic matter, sediment anoxia, a decoupling of nitrification-denitrification, and a flux of N and P out of the sediments to the overlying water. The availability of DO in the surface sediments of the second studied cell led to improved coupling between nitrification-denitrification and a net uptake of both NH4+ and PO4(3-). We hypothesise that the dominance of deeply rooted macrophytes in the second cell was responsible for the improved sediment quality.

[Applications of synchrotron-based X-ray absorption near-edge structure spectroscopy in identifying solid state phosphorus speciation: a review]

Solid state phosphorous is an important phosphorus speciation controlling the phosphorous bioavailability and mobility in the environment. Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy, with its unique advantage of being a non-destructive method in identifying the local chemical information of target element at molecular level in situ, has become one of the frontier technologies for characterizing the speciation of chemical substances and clarifying the microscopic mechanisms of chemical reactions, attracting extensive attention in the field of environmental chemistry. This paper briefly introduced the basic theory of phosphorus XANES spectroscopy, summarized the applications of XANES spectroscopy in the researches of solid state phosphorus speciation in minerals, soils, and organic fertilizers, and analyzed the challenges and prospects of the applications of XANES spectroscopy in identifying the solid state phosphorus speciation in the environmental samples. It was pointed out that XANES spectroscopy should combine with other microscopic spectroscopic techniques and macroscopic analytical methods, complementing each other, to provide a comprehensive and effective technical support for the research of the speciation characterization and transformation mechanisms of phosphorus in the environment.

Spectroscopic approaches for phosphorus speciation in soils and other environmental systems

In the past decades, environmental scientists have become increasingly involved in developing novel approaches for applying emerging spectroscopic techniques to complex environmental matrices. The objective of this review is to convey the most common chemical species of phosphorus reported for soils, sediments, model systems, and waste materials based on analyses by four spectroscopic techniques: X-ray absorption near-edge structure, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and Raman spectroscopy. Unique information is provided by each technique at a level of specificity that depends in part on matrix complexity. The X-ray absorption near-edge structure and nuclear magnetic resonance techniques reveal inorganic and organic P species in intact environmental matrices or in chemical extracts, whereas the Fourier transform infrared and Raman techniques can provide more specific bonding information about mineral or adsorbed P species in model analogs of matrix components. The most common P species in soils and sediments as indicated by spectroscopy are hydroxyapatite and octacalcium phosphate minerals, phosphate adsorbed on Fe- and Al-oxides, pyrophosphates and polyphosphates, phosphate mono- and di-esters, and phosphonates. Continued advancements in spectroscopic methods should improve speciation-based models of P mobilization and transformations in the environment.

[Effect of different fertilizing levels on yields and efficiency components of Pinellia ternata from Sichuan]

OBJECTIVE

The effect of the different fertilizing levels on yields and main active components of Pinellia ternata from Sichuan was studied under the cultivated condition, in order to provide theoretical basis for the standardized cultivation.

METHOD

Using one of the wild populations of P. ternate from Sichuan as tested material, the experiment was performed with orthogonal designing methods L25 (5(3)). During growth and development period, agronomic traits such as number of sprouting, inflorescence and bulblets were counted. After harvesting, main chemical compositions, growth and proliferation rates were determined.

RESULT

In different fertilizing levels, the P. ternata from Sichuan showed the same growth rhythm, though there were significant difference (P < 0.05) among the average emergence rate,whereas extremely significant difference (P < 0.01) were detected among the average ratio of bolting, the average bulbils, individual growth rate, individual proliferation rate, beta-sitosterol and alkaloid content under different fertilizing levels. Nitrogenous fertilizer that affected the content of alkaloids and beta-sitosterol were extremely significant (P < 0.01), whereas phosphate and potassium fertilizer had no significant effect. The effect of fertilizer factor and inter effects on beta-sitosterol showed no significant effect, but have influence on other indexes.

CONCLUSION

The optimum fertilizer composition was 315 kg x hm(-2) of nitrogen, 225 kg x hm(-2) of P2O5 and 270 kg x hm(-2) of K2O.

[Determination of phosphorus oxychloride in the air of workplace by ion chromatography]

OBJECTIVE

To establish a ion chromatography method for determination of phosphorus oxychloride in the air of workplace.

METHOD

The phosphorus oxychloride in the air of workplace was collected by absorb liquid and turned into hydrochloric acid, then separated in column and detected with conductivity detector, qualified by elution time and quantified by peak height or peak area.

RESULTS

The linear range of phosphorus oxychloride in air of workplace was 0.72 ∼ 5.76 µg/ml with its correlation coefficient 0.9999. The detecting limit of the method was 0.12 µg/ml. The smallest detecting concentration of the method was 0.08 mg/m(3) for 15 L sampling air. Relative standard deviation was 3.3% ∼ 6.2% and the recovery was 97.8% ∼ 103.8%. The sample could be resaved at room temperature at least for seven days.

CONCLUSION

The indicators of the method correspond GBZ/T 210.4-2008«Guide for establishing occupational health standards-Part 4: Determination methods of air chemicals in workplace». It is a good method to determine phosphorus oxychloride in the air of workplace.

On the fit of statistical and the k-C* models to projecting treatment performance in a constructed wetland system

The objective of this study was to assess the suitability of statistical and the k-C* models to projecting treatment performance of constructed wetlands by applying the models to predict the final effluent concentrations of a pilot field-scale constructed wetlands system (CWs) treating animal farm wastewater. The CWs achieved removal rates (in g/m(2).d) ranging from 7.1-149.8 for BOD(5), 49.8-253.8 for COD and 7.1-47.0 for NH(4)-N. Generally, it was found that the statistical models developed from multiple regression analyses (MRA) were stronger in predicting final effluent concentrations than the k-C* model. However, both models were inadequate in predicting the final effluent concentrations of NO(3)-N. The first-order area-based removal rate constants (k, m/yr) determined from the experimental data were 200.5 for BOD(5), 80.1 for TP and 173.8 for NH(4)-N and these indicate a high rate of pollutant removal within the CWs.

Identification of organic phosphorus compounds in the Bronx River bed sediments by phosphorus-31 nuclear magnetic resonance spectroscopy

Sediment characteristics influence the distribution and bioavailability of phosphorus (P) in rivers and lakes. The objectives of this study were to identify P compounds in sediments collected from 15 sites along the Bronx River to get insights on nutrient transport for management of highly variable and modified ecosystems such as the Bronx River. The nuclear magnetic resonance spectra showed that the dominant P species in Bronx River bed sediments are orthophosphate monoester and lesser phosphate diesters and pyrophosphates (pyro-P). The P compounds were mostly glycerophosphate, nucleoside monophosphates, and polynucleotides. A few sites showed a small amount of dihydroxyacetone phosphate, inosine monophosphate. By allowing a downstream comparison of P compound variations along the Bronx River, this study provides a step toward improving water quality in an urban river system such as New York City and helps to assess the bioavailability of P, in turn, design estuary habitat restoration projects in comparable region of the world.

Phosphorus composition in sediments from seven different trophic lakes, China: a phosphorus-31 NMR study

Information on the chemical composition of sediment phosphorus (P) is fundamental to understanding P dynamics and eutrophication in lake ecosystems. In this study, the surface (10 cm) sediments were collected from seven lakes representing two contrasting ecological areas in China: the middle and lower reaches of Yangtze River region and the Southwestern China Plateau. Phosphorus in these sediments was extracted by NaOH-EDTA and characterized by solution 31P nuclear magnetic resonance spectroscopy. Results show that P in the extracts was dominated by inorganic orthophosphate (76.7-97.4% of the extracted P) and orthophosphate monoesters (1.8-14.3%), with smaller amounts of orthophosphate diesters (0.4-8.9%), pyrophosphate (0.1-0.7%), and phosphonates (0.1-0.2%). The relative abundance of orthophosphate was higher in hypertrophic and shallow lake sediments than in eutrophic and mesotrophic and deep lake sediments, whereas the relative abundance of orthophosphate monoesters was the opposite. These observations suggested that the relative abundance of the two types of P forms in sediments might be related to the degree of lake eutrophication.

IRIS-HSVD algorithm for automatic quantitation of in vivo 31P MRS

The rapid development of (31)P magnetic resonance spectroscopy (MRS) has enhanced non-invasive measurement of brain metabolites, which is important for biomedical research. The accuracy and efficiency of data post processing and quantification is paramount for MRS applications. One of the difficulties with in vivo(31)P MRS data quantification is the separation of broad line-width resonances from chemical compounds' resonances under a low signal-to-noise ratio condition. Furthermore, the chemical shift of some compounds caused by pH and Mg(2+) concentration can be troublesome. This work aims to develop an automatic algorithm using a state-space based quantification approach to solve the above mentioned problems. To achieve this aim, we utilized an HSVD based adaptive optimizing prior knowledge algorithm, which uses so called "interference" signals to optimize prior knowledge iteratively for parameter optimization. We termed this algorithm IRIS-HSVD, which stands for Iterative Reduction of Interference Signal HSVD. The Monte Carlo evaluations of the algorithm were conducted with simulated data using in vivo parameters commonly obtained from a 4T scanner. The performance of this algorithm using simulated data was compared to those of other automatic methods including HSVD and HTLS-PK. Examples of in vivo(31)P data obtained from brains of healthy subjects on a 4T MRI scanner were also presented, which demonstrated the superiority of the new method. The results were compared with those using AMARES.

Distribution of phosphorus compounds in corn processing

Distillers dried grains with solubles (DDGS) and corn gluten feed (CGF) are major coproducts of ethanol production from corn dry grind and wet milling facilities, respectively. These coproducts contain important nutrients, nevertheless, high levels of phosphorus (P). About 50-80% of the P in these products is in an organically bound form known as phytate. The phytate P in these products cannot be digested by nonruminant animals. Consequently, large quantities of phytate are deposited into the soil with the animal wastes which potentially could cause P pollution in soil and underground water resources. As regulations on the concentration of P material in ethanol production coproducts become more restrictive, measures need to be taken for effective extraction of phytate P from the coproducts to make these processes more environmentally compatible. Proper marketing of coproducts is critical to the overall economy of ethanol production facilities. In this study, distribution of P compounds in different streams of dry grind and wet milling operations was determined. In the dry grind process, the highest P concentration was found to be in the condensed distillers solubles (CDS) at about 1.34 wt.% (db). About 59% of P in this stream was in phosphates form. The highest concentration of P in the wet milling process was found in the light steep water at about 3.4 wt.% (db). In this stream, about 22% of P was attributed to phosphates.

Ternary blends containing demercurated lighting phosphor and MSWI fly ash as high-performance binders for stabilizing and recycling electroplating sludge

This paper describes the solidification and stabilization of electroplating sludge treated with a high-performance binder made from portland type-I cement, municipal solid waste incineration fly ash, and lighting phosphor powder (called as cement-fly ash-phosphor binder, CFP). The highest 28-day unconfined compressive strength of the CFP-treated paste was 816 kg/cm(2) at a ratio of cement to fly ash to lighting phosphor powder of 90:5:5; the strength of this composition also fulfilled the requirement of a high-strength concrete (>460 kg/cm(2) at 28 days). The CFP-stabilized sludge paste samples passed the Taiwanese EPA toxicity characteristic leaching procedure test and, therefore, could be used either as a building material or as a controlled low-strength material, depending on the sludge-to-CFP binder ratio.

Evaluation of natural and anthropogenic influences on the Guadalquivir River (Spain) by dissolved heavy metals and nutrients

To evaluate both the natural and anthropogenic influences on surface waters of Guadalquivir River (SW-Spain), concentrations of dissolved trace metals (Mn, Co, Ni, Cu, Cd, Zn, and Pb), inorganic nutrients (N-NH(4)(+), N-NO(3)(-), N-NO(2)(-), and P-PO(4)(3-)) and other variables as conductivity, pH, dissolved oxygen (DO) and suspended solids (SS) were measured during a three-years period (2001-2003). Samples were taken at 26 stations twice a year, during rain and dry periods. The analysis of variance (ANOVA) suggested that temporal variations within the period of study were statistically negligible. Spatial distributions identified three different zones, mainly influenced by sewage (Eastern Zone), agriculture runoffs (Central Zone), and estuarine processes (Western Zone), respectively. Principal Component and Cluster Analysis allowed to identify the variables controlling the water quality of each zone as: N-NH(4)(+), N-NO(2)(-), Mn, and Co, (Eastern Zone), SS, and P-PO(4)(3-) (Central Zone), and Cd, pH and conductivity (Western Zone). Other variables such as Ni, Cu, Zn or N-NO(3)(-), influenced two different zones, while Pb presented a singular behavior.

31P MR Spectroscopy in Assessment of Response to Antiviral Therapy for Hepatitis C Virus–Related Liver Disease

OBJECTIVE

An increase in the ratio of phosphomonoester (PME) to phosphodiester (PDE) during 31P MR spectroscopy of the liver has been observed with increasing severity of hepatitis C-related liver disease. The purpose of this study was to investigate the utility of 31P MR spectroscopy as a biomarker of response to interferon and ribavirin treatment.

SUBJECTS AND METHODS

Forty-seven patients with biopsy-proven hepatitis C undergoing viral eradication treatment with interferon and ribavirin underwent hepatic 31P MR spectroscopy at 1.5 T (voxel size, 70 x 70 x 70 mm; TR, 10,000; number of signals averaged, 48). All underwent baseline imaging before treatment and repeated imaging at 6-month intervals after the start of treatment.

RESULTS

All patients underwent follow-up imaging 6 months after the start of treatment; 25 patients, 12 months; and 10 patients, 18 months after the start of treatment. According to the Ishak histologic scoring system, nine patients had mild hepatitis; 30 patients, moderate to severe hepatitis; and eight patients, cirrhosis. Thirty-two patients responded to antiviral treatment. Among these patients, 25 had a decrease in PME/PDE ratio on follow-up imaging. Among responders the mean baseline PME/PDE ratio decreased from 0.27 +/- 0.02 (standard error) to 0.16 +/- 0.01 after treatment (paired Student's t test, p < 0.001). Among the 15 virologic nonresponders, the ratios were similar in six patients; six other patients had an increase on follow-up imaging. In the latter nonresponder group, the mean baseline PME/PDE ratio was 0.21 +/- 0.03 compared with 0.31 +/- 0.08 after treatment (paired Student's t test, p =0.24).

CONCLUSION

The in vivo hepatic PME/PDE ratio decreased in patients with hepatitis C who responded to antiviral treatment and remained similar or increased in patients without a virologic response. These results suggest that PME and PDE can be used as biomarkers in a noninvasive test of response to treatment.

Phosphorus load reduction goals for Feitsui Reservoir Watershed, Taiwan

The present paper describes an effort for developing the total maximum daily load (TMDL) for phosphorus and a load reduction strategy for the Feitsui Reservoir in Northern Taiwan. BASINS model was employed to estimate watershed pollutant loads from nonpoint sources (NPS) in the Feitsui Reservoir watershed. The BASINS model was calibrated using field data collected during a 2-year sampling period and then used to compute watershed pollutant loadings into the Feitsui Reservoir. The simulated results indicate that the average annual total phosphorus (TP) loading into the reservoir is 18,910 kg/year, which consists of non-point source loading of 16,003 kg/year, and point source loading of 2,907 kg/year. The Vollenweider mass balance model was used next to determine the degree of eutrophication under current pollutant loading and the load reduction needed to keep the reservoir from being eutrophic. It was estimated that Feitsui Reservoir can becoming of the oligotrophic state if the average annual TP loading is reduced by 37% or more. The results provide the basis on which an integrated control action plan for both point and nonpoint sources of pollution in the watershed can be developed.

Dynamics of phosphorus, nitrogen and carbon removal in a horizontal subsurface flow constructed wetland

The dynamics of nitrogen (N), phosphorus (P) and carbon (C) accumulation in the filter material of a horizontal subsurface constructed wetland (HSSF CW; established in 1997) and in a specially designed oil-shale ash filter (2002) for P retention have been studied. Concentrations of N, P and C in filter media (coarse sand) in the HSSF beds show an increasing trend. Both the annual accumulation of P and increasing outflow concentrations of P in the HSSF CW reflect the possible saturation of filter media with P after 8 years working. Tested ash material derived from oil-shale combustion demonstrated very high P removal efficiency in laboratory batch experiments. However, during the first 4 months of the in situ ash filter experiment, the efficiency of P removal was about 71% (an average outflow concentration of 1.9 mg L(-1) was achieved). Subsequently, the efficiency decreased to 10-20%, which might be a sign of saturation or clogging due to quick biofilm development on the ash particles. The increasing of hydraulic retention time and the improvement of design for maximal contact between material and wastewater are considered to be key factors that can provide optimal pH for the removal processes.

Temporal and spatial variation of phosphate distribution in the sediment of a free water surface constructed wetland

This study was aimed at determining the spatial and temporal variation of P distribution in sediment of an artificial wetland for sewage and industrial wastewater treatment, and the fraction that is potentially involved in the P exchange processes. Influent, effluent, macrophytes and sediment at the inlet, middle and outlet areas were sampled over 24 months. The P-fractionation in sediment was performed following the EDTA method. Eichhornia crassipes and Typha domingensis removed P efficiently when cover was high, but E. crassipes caused anoxic conditions. The increase in cover of T. domingensis may contribute to attain oxic conditions and to improve P removal. When macrophytes are not present or when cover is low, sediment seems to increase removal efficiency. A significant increase in the concentration of the fraction of Fe(OOH) approximately P and mainly that of CaCO(3) approximately P can be observed at the inlet. High pH, Ca(2+) and CO(3)(-)(2) concentrations in the influent suggest that P co-precipitates together with CaCO(3). Therefore, it seems that CaCO(3) approximately P represents the main precipitating mechanism. However, mineralization of organic matter maintained the sediment at a pH range lower than the high values prevailing in the influent. CO(3)(-)(2) could undergo partial dissolution and the released i-P(diss) could be readsorbed onto the Fe(OOH) approximately P fraction. Since the environment for P retention (high pH, Fe, Ca and ionic concentrations) is largely provided by the influent, the wetland may be expected to continue retaining P as far as the composition of the influent is maintained and there are available adsorption sites in the sediment.

Nitrogen and phosphorus dynamics of a re-wetted shallow-flooded peatland

Minerotrophic peatlands play an important role in the regulation of water quality and quantity but due to drainage and agricultural land use most of these systems have lost this function. In Central Europe, many re-wetting projects have been implemented to restore wetlands for multifunctional purposes during the last years. The Pohnsdorfer Stauung (Northern Germany) is a eutrophic fen which was used for intensive agriculture for 40 years. The peatland is divided in two subareas by a small stream. In the scope of re-wetting measures, one subarea (westpolder) was flooded by blockading the main drainage ditch in 1996/97, a second subarea (eastpolder) was re-connected to the stream by an inlet and outlet in 2001. Nitrogen and phosphorus dynamics were investigated in the surface water of these systems over a 5-year (westpolder) and 3-year (eastpolder) period, and balances were calculated. In both polders high dynamics of nitrogen and phosphate concentrations were observed in the surface water. Nitrate peaked in the winter months, whereas ammonium, phosphate and organically bound nitrogen (N(org)) revealed highest values during summer. Daily balances for the eastpolder and annual balances for both polders were calculated. In both polders nitrate was retained but phosphate and N(org) were exported. Differences of the nutrient dynamics and the absolute and relative balances between the polders were due to the different hydrology: the eastpolder received a high nitrate load by the stream, in the westpolder nutrient loads are low and internal nutrient cycles are dominating. During the summer months, high ammonium concentrations, oxygen depletion, and phosphate release occur in the warm, stagnant water of both polders. Normally, high phosphate and ammonium concentrations did not coincided with discharge phases from the polders. However, in August 2002 after heavy rainfall high phosphorus and ammonium discharge was observed. One important factor influencing the detected nutrient dynamics and balances is the change from a drained and fertilized peatland to a flooded wetland in only a few years. We conclude that continuous water flow and stable water levels are desired for flooded peatlands to prevent high concentrations of ammonium and phosphate and to utilize the potential for nitrate retention. In degenerated peatlands, flooding should only be regarded as an easy technological solution in order to conserve the peat mineralization, and to form the foundation for the further development of the peatland to a more efficient nutrient retaining system.

Removal of nutrients in various types of constructed wetlands

The processes that affect removal and retention of nitrogen during wastewater treatment in constructed wetlands (CWs) are manifold and include NH(3) volatilization, nitrification, denitrification, nitrogen fixation, plant and microbial uptake, mineralization (ammonification), nitrate reduction to ammonium (nitrate-ammonification), anaerobic ammonia oxidation (ANAMMOX), fragmentation, sorption, desorption, burial, and leaching. However, only few processes ultimately remove total nitrogen from the wastewater while most processes just convert nitrogen to its various forms. Removal of total nitrogen in studied types of constructed wetlands varied between 40 and 55% with removed load ranging between 250 and 630 g N m(-2) yr(-1) depending on CWs type and inflow loading. However, the processes responsible for the removal differ in magnitude among systems. Single-stage constructed wetlands cannot achieve high removal of total nitrogen due to their inability to provide both aerobic and anaerobic conditions at the same time. Vertical flow constructed wetlands remove successfully ammonia-N but very limited denitrification takes place in these systems. On the other hand, horizontal-flow constructed wetlands provide good conditions for denitrification but the ability of these system to nitrify ammonia is very limited. Therefore, various types of constructed wetlands may be combined with each other in order to exploit the specific advantages of the individual systems. The soil phosphorus cycle is fundamentally different from the N cycle. There are no valency changes during biotic assimilation of inorganic P or during decomposition of organic P by microorganisms. Phosphorus transformations during wastewater treatment in CWs include adsorption, desorption, precipitation, dissolution, plant and microbial uptake, fragmentation, leaching, mineralization, sedimentation (peat accretion) and burial. The major phosphorus removal processes are sorption, precipitation, plant uptake (with subsequent harvest) and peat/soil accretion. However, the first three processes are saturable and soil accretion occurs only in FWS CWs. Removal of phosphorus in all types of constructed wetlands is low unless special substrates with high sorption capacity are used. Removal of total phosphorus varied between 40 and 60% in all types of constructed wetlands with removed load ranging between 45 and 75 g N m(-2) yr(-1) depending on CWs type and inflow loading. Removal of both nitrogen and phosphorus via harvesting of aboveground biomass of emergent vegetation is low but it could be substantial for lightly loaded systems (cca 100-200 g N m(-2) yr(-1) and 10-20 g P m(-2) yr(-1)). Systems with free-floating plants may achieve higher removal of nitrogen via harvesting due to multiple harvesting schedule.

Evaluation of the influence of albumin on the mineralization of a glass by Atomic Force Microscopy

Bioactive glasses have been used as a graft material that can stimulate the formation of a new bone. In vitro tests usually give sensible indications about the potential bioactivity of these glasses. In the present work the influence of egg albumin on the formation of a Ca-P precipitate on a glass of the system SiO(2)-CaO-MgO-P(2)O(5) was evaluated. The samples were immersed in simulated body fluid (SBF) that simulates the composition of human plasma, with and without albumin. After immersion in this solution for 7 and 14 days, the glass was characterized by X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM). AFM results of the samples after immersion in SBF with albumin show the development of a precipiate formed from the solution/substrate reaction. Glasses immersed in albumin-free SBF exhibit the formation of a thin layer easily detached from the substrate. XRD results indicate that the precipitate is essentially amorphous, evolving to octacalcium phosphate. As the formation of an adherent precipitate on the glass samples only occurred when the substrate was immersed in SBF with albumin, it is suggested that albumin improves the mineralization on the glasses.

The determination of phosphorus containing compounds in dental casting investment products by 31P solid-state MAS-NMR spectroscopy

OBJECTIVES

To use (31)P solid-state MAS-NMR to determine the phosphorus compounds that occur in dental casting investment material: (a) as-received, (b) after setting and (c) after burn-out and discover whether such compounds are the same in each material across a product range.

METHODS

[(1)H] High powered decoupling (HPDC) and [(1)H] cross-polarization (CP) (31)P solid-state MAS-NMR spectroscopy at a resonance frequency of 121.4 MHz were used. Six commercial products were examined. Manufacturer's instructions were followed and a special liquid was used without dilution.

RESULTS

All products contain ammonium dihydrogen phosphate as the acid phosphate required for the setting reaction. All set by the formation of struvite and significant amounts of amorphous magnesium orthophosphate. In three products, lesser amounts of newberyite were present and in another the equivalent amorphous compound was formed. When burnt-out, magnesium metaphosphate or pyrophosphate was the dominant matrix compound. A higher burn-out temperature favoured pyrophosphate formation. Farringtonite was present to a lesser extent with the metaphosphate.

SIGNIFICANCE

Compounds that were not detected in earlier X-ray powder diffraction spectroscopy studies were detected by NMR, notably amorphous and glassy compounds (magnesium orthophosphate in set investment and magnesium metaphosphate in burnt-out material). The variation between products was significant and far greater than expected from the published scientific literature. Since the formation of compounds is affected by technical procedure and ambient conditions, these findings could offer some insight into the cause of the unpredictability of expansion measurements between laboratories. Further research is being undertaken.

Biogenic phosphorus in oligotrophic mountain lake sediments: differences in composition measured with NMR spectroscopy

Phosphorus (P) composition in alkaline sediment extracts from three Swedish oligotrophic mountain lakes was investigated using 31P-NMR spectroscopy. Surface sediments from one natural lake and two mature reservoirs, one of which has received nutrient additions over the last 3 years, were compared with respect to biogenic P composition. The results show significant differences in the occurrence of labile and biogenic P species in the sediments of the different systems. The P compound groups that varied most between these three systems were pyrophosphate and polyphosphates, compound groups known to play an important role in sediment P recycling. The content of these compound groups was lowest in the reservoirs and may indicate a coupling between anthropogenic disturbances (i.e., impoundment) to a water system and the availability of labile P species in the sediment. A statistical study was also conducted to determine the accuracy and reliability of using 31P-NMR spectroscopy for quantification of sediment P forms.

Comparison of high-performance liquid chromatography of cyclotriphosphazene derivatives with one or two equivalent stereogenic centres

High-performance liquid chromatographic (HPLC) methods have been developed for investigating the stereogenic properties of two analogous series of dibenzylamino derivatives of cyclotriphosphazene containing either one or two equivalent stereogenic centres. Separation of the enantiomers of all the racemic compounds has been investigated by chiral HPLC using Whelk-01 and Chiralcel OD columns. In all cases, conditions for separation of enantiomers have been found using a Whelk-01 column with different ratios of tetrahydrofuran in n-hexane as the mobile phase. It is found that both the separation factor (alpha) and resolution factor (R(S)) of molecules with two equivalent stereogenic centres are greater than those for analogues with only one centre.

In vivo 31P MR spectral patterns and reproducibility in cancer patients studied in a multi-institutional trial

The standardization and reproducibility of techniques required to acquire anatomically localized 31P MR spectra non-invasively while studying tumors in cancer patients in a multi-institutional group at 1.5 T are reported. This initial group of patients was studied from 1995 to 2000 to test the feasibility of acquiring in vivo localized 31P MRS in clinical MR spectrometers. The cancers tested were non-Hodgkin's lymphomas, sarcomas of soft tissue and bone, breast carcinomas and head and neck carcinomas. The best accrual and spectral quality were achieved with the non-Hodgkin's lymphomas. The initial analysis of the spectral values of the sum of phosphoethanolamine plus phosphocholine normalized by the content of nucleotide triphosphates in a homogeneous sample of 32 NHL patients studied by in vivo (31)P MRS showed good reproducibility among different institutions. No statistical differences were found between the institution with the largest number of cases accrued and the rest of the multi-institutional NHL data (2.28 +/- 0.64, mean +/- standard error; n = 17, vs 2.08 +/- 0.14, n = 15). The preliminary data reported demonstrate that the institutions involved in this trial are obtaining reproducible 31P MR spectroscopic data non-invasively from human tumors. This is a fundamental prerequisite for the international cooperative group to be able to demonstrate the clinical value of the normalized determination of phosphoethanolamine plus phosphocholine by 31P MRS as predictor for treatment response in cancer patients.

Residue formations of phosphorus hydride polymers and phosphorus oxyacids during phosphine gas fumigations of stored products

With the extent of international usage and the critical role phosphine gas (PH3) plays in commercial pest control, identification of the residual components deposited during fumigation is mandatory. It has been postulated that these infrequent residues are primarily composed of phosphoric acid or reduced forms of phosphoric acid [hypophosphorous acid (H3PO2) and phosphorous acid (H3PO3)], due to the oxidative degradation of phosphine. Using environmental scanning electron microscopy, gas phase Fourier transform infrared spectroscopy, and X-ray fluorescence spectroscopy, the structural elucidation and formation mechanism of the yellow amorphous polyhydric phosphorus polymers (P(x)H(y)) that occur in addition to the lower oxyacids of phosphorus in residues deposited during PH3 fumigations of select tobacco commodities are explored. This research determined that nitric oxide gas (or nitrogen dioxide) initiates residue formation of phosphorus hydride polymers and phosphorus oxyacids during PH3 fumigations of stored products.