Phosphorus Contamination Research Articles

Preliminary study of phosphorus runoff and drainage from a paddy field in the Taihu Basin.

An investigation into phosphorus runoff and drainage from a paddy field was carried out at Changshu Agricultural Ecological Station of CAS during the year 2000. According to the preliminary study, some results indicated: (1) Total phosphorus (TP) content of regular irrigation water was 19 times higher than TP content of P0 (zero rate of P fertilization) stand water. This indicates that paddy fields are a potential source of phosphorus pollution by runoff and drainage into the Taihu Lake Basin (TLB); (2) During the first 10 days after phosphate fertilizer application, the TP concentration of stand water in the paddy field was very high, therefore this was the high risk period for Taihu Lake phosphorus contamination; (3) Four mathematical models of P losses from a paddy field in the TLB are developed. These are based on data for the year 2000, but they will be improved as more data is acquired in future years.

Protein pattern of exhaled breath condensate and saliva.

The proteins recovered in exhaled breath condensate (EBC) might be used to non-invasively monitor respiratory diseases. However, the range of proteins and their source are still unresolved and contamination by saliva or a similar protein pattern in the nasal and bronchial compartments may make interpretation of the data difficult. We studied nasal EBC (collected through a "free of touch" technique by negative pressure), oral tidal, and oral forced EBC (collected through a rebreathing valve as a saliva trap connected to tubing submerged into ice) and matched saliva samples from five healthy adult subjects. The protein samples were separated by two-dimensional electrophoresis and the silver stained gels were analyzed by Melanie 2 software. In both nasal and oral EBC, three spots (72 kDa/isoelectric point (pI) 6.6-7.0, 66 kDa/pI 5.9-6.7 and 45-48 kDa/pI 8.0-8.6) were consistently present in all subjects. Several other proteins were only sporadically detected. Despite improbable saliva contamination (no phosphorus contamination in the same oral and nasal EBC, no amylase activity in 10 pairs of nasal and oral EBC collected by the same technique), on average 63% and 71% of the spots identified in oral and nasal EBC were also found in the matched individual saliva samples. Compared to saliva, the range and amount of protein in all types of EBC was very small. Even when collected free of saliva contamination the majority of proteins present in EBC was also found in saliva, suggesting that these proteins are present in both compartments, e.g. saliva and secretions of the lower airspaces. The quantification and identification of specific proteins in the various compartments is warranted in future studies to determine the practical value of EBC.

Modeling the Response of Water Quality in the Seine River Estuary to Human Activity in Its Watershed over the Last 50 Years

The unique database of water quality measurements made in the Seine estuary over 45 years by the Service de la Navigation de la Seine at Rouen is used here to reconstruct the evolution of oxygen status in the estuary and the nutrient fluxes to the Seine Bight during the last half century. The Riverstrahler model is used to establish the link between these long-term trends in the functioning of the Seine system and the evolution of agricultural, domestic, and industrial activity in the watershed over this period taking into account natural and man-induced hydrological variations. Oxygenation of the fluvial sector below Paris has increased considerably owing to improved wastewater treatment, but a large part of the estuary remains completely anoxic during the spring and summer months. Nitrogen input to surface waters from urban sources has remained essentially constant while diffuse inputs from agricultural soils have increased 5-fold as a result of more intensive agricultural practices as well as the loss of retention capacity in riparian zones. Phosphorus inputs from domestic and industrial sources increased 3-fold from 1950 to 1980, but have decreased gradually in recent years. The generally high level of phosphorus contamination has favored strong algal development in all large tributaries of the Seine River upstream of paris since the 1960s. Silica inputs, originating mainly from the weathering of rocks, fluctuate widely depending on hydrology. In-stream retention of silica, linked to diatom blooms, has increased but remains limited. These changes have induced several shifts in the nutrient limitation conditions of the Seine Bight.

Characterization of phosphorus-poisoned automotive exhaust catalysts

Oil-derived contaminants on light-off catalysts from high mileage taxis were characterized by a variety of physical and chemical methods. The contaminants (mostly phosphates) deposit in a strong axial gradient from the front to the back of the monolithic catalyst channels. Two major forms of phosphorus contamination were observed: (1) an overlayer of Zn, Ca, and Mg phosphates, and (2) aluminum phosphate within the washcoat. The data also suggest the formation of cerium(III) phosphate. Laboratory catalytic reaction measurements on core samples from the taxi catalysts confirm a strong deactivating effect due to the phosphorus contamination. The activity improves dramatically after removing phosphorus via an oxalic acid wash.

A simple vapour phase decomposition (VPD) of quartz powder in a polypropylene vessel and determination of phosphorus by spectrophotometry

A simple, low pressure, low temperature vapour phase decomposition (VPD) of quartz powder has been developed for the determination of phosphorus. A platinum dish containing the quartz or silicon powder was placed inside a polypropylene vessel containing 40 ml of 1:1 mixture of HF and HNO 3. After capping the vessel, the entire assembly was heated on a water bath at ∼90 °C for 8 h. The platinum dish was removed from the vessel, the sample solution was treated with 0.5 ml of H 2SO 4 and 0.5 ml of HClO 4 and was heated on a hot plate till HClO 4 fumed out. The resultant solution was diluted to 40 ml (∼0.4N), analysed for phosphorus by spectrophotometry as an ion-pair of molybdophosphate with crystal violet. Phosphorus contamination by reagents has been drastically reduced (around 250 times) compared to the conventional dissolution procedure. The optimum reaction conditions were [H +]=0.42N, [H +]/Mo=62 for the formation of molybdophosphate and its extraction into n-butyl acetate. No interferences due to fluoride, silicate (active silica) and arsenic ( V) upto 6.7×10 3, 2.7×10 3 and 2.0×10 3 times the content of phosphorus, respectively were observed. The LOD was found to be 0.066 μg g −1 (±3 s). RSD is 0.4–2.3% and the molar absorptivity is 2.7×10 5 l mole −1 cm −1.

Method for Attenuation of White Phosphorus Contamination in Wetlands

White phosphorus, a manufactured form of elemental phosphorus, is both toxic and persistent in saturated environments. This form of phosphorus (P 4 ) is used by militaries worldwide as a component for obscurants, tracer rounds, and incendiary munitions. At Eagle River Flats, an estuarine salt marsh located on Fort Richardson, Alaska, white phosphorus has been directly linked through carcass analysis to the deaths of thousands of dabbling waterfowl. Particulate residue from ordnance contaminates the permanently ponded areas of Eagle River Flats, where the waterfowl sieve the soft bottom sediments for food items, picking up P 4 particles in the process. Death follows within hours. Large-scale investigations into the nature, extent, and persistence of the contaminant were initiated in 1989, followed 4 years later by work on the testing and analysis of remediation methods. In 1997, a method for in situ remediation of the contaminant through low-impact pumping and draining of ponded areas to enhance natural attenuation of white phosphorus was tested. Results indicate that pond pumping is a very effective remediation technique.

370 Iron and Iron Compounds Reduce Phosphorus Leaching from Nursery Containers

Phosphorus contamination of surface water is a growing problem associated with container production of nursery plants. Iron and iron compounds have the ability to adsorb phosphorus and render it immobile. Incorporating iron compounds into media at the base of nursery containers serves to filter out phosphorus from fertilizers while still allowing the plant to collect enough phosphorus to grow. Two experiments were devised. The first experiment examined how much phosphorus various iron compounds would adsorb. Metallic iron adsorbed the most phosphorus, followed by HCl reacted magnetite (a form of iron ore), Fe2O3, Fe3O4 and magnetite. In the second experiment, PVC tubes (4 cm inner diam.) were filled to a level of 5 cm with a phosphorus adsorbing layer containing growing media that was 25% or 50% by weight iron compounds. Compounds included metallic iron, HCl reacted magnetite and magnetite. Plain media was used as a control. A layer of 15 cm of media and slow-release fertilizer was applied above the adsorptive layer. One hundred milliliters of distilled water was applied to PVC tubes daily to simulate irrigation. Metallic iron reduced phosphorus leachate to almost 0 for over 2 weeks. HCl reacted magnetite was also effective in reducing phosphorus leachate. Magnetite only affected phosphorus leachate slightly.

Ruminal phosphorus availability from several feedstuffs measured by the nylon bag technique.

The present study was aimed at determining rumen phosphorus availability of some feedstuffs assessed with the nylon bag technique: forage (alfalfa), cereals (control-C wheat, formaldehyde treated-FT wheat, barley, corn), cereal by-products (wheat bran, wheat distillers, corn distillers) and meals (C and FT soya bean meals, rapeseed meals and sunflower meals). Rumen phosphorus availability was not uniform amongst the feedstuffs, varying from 33.1% (FT rapeseed meal) to 84.7% (C wheat). Alfalfa phosphorus release kinetics showed high bacterial phosphorus contamination. Technological treatments affected phosphorus content of by-products by either increasing (wheat bran and distillers) or decreasing (corn distillers) after germ extraction from the seed. Formaldehyde treatment decreasing rumen phosphorus availability (from 77.2% vs. 89.4% for wheat to 33.1% vs. 64.4% for the rapeseed meal) may depreciate the phosphorus nutritional value of FT meals.

Remediation methods for white phosphorus contamination in a coastal salt marsh

With the closure of many military bases worldwide and a closer scrutiny of practices on remaining bases, the environmental impact of the military is now an important consideration in the operation of bases. Many previously-unknown environmental problems related to chemicals are surfacing. White phosphorus, a chemical commonly used as an obscurant, is a chemical previously thought to be innocuous after use. In 1990, however, it was linked to the deaths of thousands of waterfowl at the Eagle River Flats impact area on Ft Richardson near Anchorage, Alaska, USA, and shortly after, a series of remedial investigations was initiated. This paper describes three of the remedial methods currently under investigation, namely enhanced in-situ remediation, pond draining through ditching or pumping, and dredging. These three approaches are best applied in different environments, but they can be used together or in conjunction with other strategies. Their impacts on the environment will vary as well.Experience with these remediation strategies has proven very useful in determining the direction that the clean-up effort at Eagle River Flats (ERF) should take. Dredging, an effective means of removing contaminated sediments for off-site remediation, has been shown to be too slow and expensive at the ERF because unexploded ordnance is present. Enhanced natural remediation is effective under favourable climatological conditions in areas that experience intermittent flooding, but desaturation of the sediments is critical to its effectiveness. Pond draining by blasting a ditch effectively removes waterfowl feeding habitat, but attenuation of the contaminant is inhibited because the ditch increases flooding frequency, and the habitat alteration is permanent. Pond pumping, where feasible, has shown great potential for the desaturating of wide areas of ERF, enabling the natural attenuation mechanism to progress. Further investigation will be necessary to confirm these initial conclusions and determine the overall effectiveness of all three methodologies. Methods developed over the course of this work may be applied to other remediation projects where in-situ volatilization can occur and limited disturbance of wetlands is critical.

Use of soil amendments to reduce soluble phosphorus in dairy soils

The objective of this research was to determine the effectiveness of soil amendments on reducing soluble P in Spodosols under dairy animal land-use. Dairy animal manure is a P source contaminating surface waters of the northern watersheds of Lake Okeechobee in south Florida. Phosphorus contamination has originated from manure-loaded soils found adjacent to milking barns, holding pens, feed lots under intensive animal use, and also developed pastures. In various batch-incubation studies, manure-loaded soils (7.0 to 120.9 g kg −1 t as total organic C) were treated alone or in combination with varying rates of calcium carbonate (to pH 7.5), gypsum (0 to 100 g kg −1 soil), ferrous sulfate (0 to 1000 mg kg −1 as Fe), and alum (0 to 1000 mg kg −1 t as Al). The influence of aerobic and anaerobic conditions on soluble P were also studied. Soluble phosphate concentrations were reduced 40 to 63% from gypsum application up to 100 mg kg −1- t soil; nitrate and soluble organic carbon concentrations were similarily reduced by 45% and 49%, respectively. Increasing water-soluble Ca and the soil pH to 7.5 decreased soluble phosphate concentrations in manure-loaded soils. Gypsum amendments were effective under a broad range of manure loading, pH, and redox conditions. Bacterial activities were also affected by gypsum-amended soils. Calcium carbonate effectiveness was limited to lower pH soils (< pH 7.0). Although Fe and Al soil amendments increased P retention to over 400% from unamended soils, source costs and questionable biological toxicities may limit their usefulness. Evidence indicated that both precipitation and microbial mechanisms are involved in P retention /desorption in soils loaded with animal manures.

The growth and characterization of AlGaAs double heterostructures for the evaluation of reactor and source quality

AlGaAs double heterostructures are grown by low-pressure metalorganic chemical vapor deposition to evaluate the level of oxygen contamination in different trimethylaluminum sources. Effects of arsine purifiers, misoriented substrates, atmospheric exposure of the growth chamber, and possible phosphorus contamination are also studied. Extensive characterization is performed on these films by a variety of methods, including high-resolution x-ray diffraction, photoluminescence (PL), time-resolved photoluminescence, and secondary-ion mass spectrometry. The PL intensities for structures grown with the low-alkoxide grade are reproducibly much greater than those grown with the regular-grade TMA1. The use of AsH3 purification improves the PL intensity.

Nitrogen and Phosphorus Contamination of Ground Water and Drainage Water in the Grassland Area : A Case Study in Konsen Upland I

Nitrogen and Phosphorus Contamination of Ground Water and Drainage Water in the Grassland Area : A Case Study in Konsen Upland I

Assessing the Diffuse Phosphorus Input from Subsurface to Surface Waters in the Catchment Area of the Lower River Spree (Germany)

The proportion of nonpoint phosphorus sources in the eutrophication process of surface waters is higher than generally assumed. In the surroundings of Berlin (glaciofluvial deposits and moraine areas) the phosphorus content of some subsurface waters reaches levels of several hundred µgP/l. As surface waters are mainly fed by groundwater in this area, nutrient contents in groundwater may become of great importance when other phosphorus sources are eliminated. Investigations in unpolluted areas are a prerequisite to decide whether higher phosphorus levels in groundwater are of natural origin or the result of contamination processes. The phosphorus background was shown to be very different and dependent on the depth below groundwater surface, content of iron, and redox conditions in the aquifer. Wastewater land treatment, bank filtration, agricultural land use, and degradation of lowland bogs were found to be sources of phosphorus contamination of aquifers. The results of observations are reported.

Potential Contamination from Glassware in the Determination of Phosphorus in Natural Waters

Abstract Phosphorus was determined in samples of glass from laboratory glassware, using a hydrofluoric digestion followed by colorimetry. Glass from such sources is shown to contain up to 0.002% of phosphorus. Experiments on storage of samples in glass bottles show that glassware may contribute significant phosphorus contamination to natural water samples, particularly seawater, as a result of partial dissolution of glass into the sample during storage. The release of phosphate from glassware into the sample is greater than the concentration expected from the P/Si ratio in glass and the silicate dissolution in the sample. This is attributed to the formation of a leached layer at the surface of the glass in contact with the water. Under the alkaline digestion conditions applied in this work for the total phosphorus determination, the dissolution of glass does not appear to be a source of measurable phosphate contamination. Nevertheless each analyst must satisfy himself that no phosphate contamination occur...

Removal of phosphorus contamination from charcoal prior to decolorisation of soil extracts

Abstract A method for washing charcoal to remove phosphorus contamination prior to decolorisation of soil extracts is reported. Washing with 6M HCl in a column was more effective than washing with the extractant solution. Leaching of the charcoal in a column allowed a more uniform washing and was less demanding of operator time than shaking and leaching through a Buchner funnel.

Dietary and Fecal Concentrations of Nitrogen and Phosphorus in Penned White-Tailed Deer Does

We evaluated fecal nitrogen (FN) and fecal phosphorus (FP) concentrations as indicators of different dietary nitrogen (DN) and dietary phosphorus (DP) levels fed to 11 penned, white-tailed deer does (Odocoileus virginianus) during summer 1985. We fed deer pelleted rations containing 2 levels of DN (2.64 and 1.18%) or DP (0.49 and 0.30%) during 2 consecutive, 16-day trials. We collected fecal pellets from each animal during the last 6 days of each trial. Pooled mean FN concentrations for corresponding high and low DN levels were as follows: total FN = 2.26 and 1.45% (P = 0.003), neutral detergent FN = 0.60 and 0.39% (P = 0.019), and metabolic FN = 1.67 and 1.06% (P = 0.001). Pooled mean FP concentrations for corresponding high and medium DP levels were as follows: total FP = 1.23 and 0.44% (P = 0.002), neutral detergent FP = 0.12 and 0.10% (P = 0.022), and endogenous FP = 1.11 and 0.33% (P = 0.002). Under controlled conditions FN and FP concentrations can be used to discern relatively large differences in DN and DP levels of whitetailed deer. J. WILDL. MANAGE. 54(3):383-389 Nutrient levels of hand-collected forages have been used as indicators of dietary quality (Cook 1964), but this is generally an unreliable method for determining diet quality of free-ranging ungulates (Theurer et al. 1976) due to the apparent ability of ungulates to select the most nutritious forage available (Swift 1948). Esophageal fistulization is usually impractical for studying diet quality of free-ranging wild ungulates (Leslie and Starkey 1985) and, moreover, is unsuitable for DP assessment due to salivary phosphorus (P) contamination (Holechek et al. 1985). Blood samples require manual restraint or death of animals and, given the complex effects of homeostatic regulation of mineral metabolism, blood P concentrations may not be sufficiently sensitive to assess P status (Underwood 1981). The use of fecal nutrient levels to study diet quality may be a feasible noninvasive alternative to other techniques that require disturbance, stress, or death of wild ungulates (Leslie and Starkey 1985). Researchers have used fecal nutrient levels to predict dietary nutrient levels in elk (Cervus elaphus) (Mould and Robbins 1981, Leslie and Starkey 1985), black-tailed deer (Odocoileus hemionus columbianus) (Leslie and Starkey 1985, Mubanga et al. 1985), white-tailed deer (Jenks et al. 1989, Leslie et al. 1989), moose (Alces alces) (Leslie et al. 1989), and domestic livestock (Belonje and Van den Berg 1980a,b; Holechek et al. 1982, 1985). The advantages (Leslie and Starkey 1987) and disadvantages (Hobbs 1987) of FN as an indicator of DN in free-ranging deer diets have been discussed, but little controlled research has been conducted to determine the utility of using fecal indices for nutrient assessment of wild ungulate diets, particularly for white-tailed deer. Leslie and Starkey (1987) argued for continued research toward refining the use of fecal indices to measure the quality of wild ungulate diets. We conducted a controlled study involving 2 consecutive feeding trials to determine whether FN and FP concentrations could be used to detect differences in DN and DP levels fed to penned, white-tailed deer does. We thank C. Schreiner IV and the Y. O. Ranch employees of Mountain Home, Texas, for their kindness, cooperation, and generous use of study pens and other facilities. Critically constructive comments on the manuscript were provided by T. J. DeLiberto, S. Demarais, and F. C. Bryant. We are grateful to E. A. Howery for assistance with data collection and tabulation and to G. R. Scott and N. C. Jordan for lab assistance. Financial support was provided by the Caesar Kleberg Foundation for Wildlife Conservation and Texas Tech University. This is publication T-9577 of The College of Agricultural Sciences, Texas Tech University, Lubbock. 'Present address: Range Science Department, Utah State University, Logan, UT 84322-5230.

Phosphorus contamination of Al-Khair river, Baghdad

Phosphorus in one of the most important biogenous substances affecting water quality and connected with water pollution from man-associated sources. Concentrations of various phosphorus forms in Al-Khair river, Baghdad, showed that its water contained high levels of phosphorus and these concentrations increased significantly down the stream where the domestic sewage effluents are discharged. Total phosphorus (TP) concentrations reached 2.65 mg L(-1) during October 1984, where total soluble phosphorus (TSP) formed the major constituent of TP at these affected sites. A flooding condition was established to dilute different species of contaminants as an attempt to control the pollution of Al-Khair river. During this stage, phosphorus concentrations decreased although the TP concentrations did not fall below 0.03 mg L(-1) (with few exceptions). Moreover, higher phosphorus concentrations were recorded during summers VS. winter months during both stages of the work. This probably was due to the internal load where TP concentrations in the bottom sediments showed also high levels of phosphorus concentration (maximum 180 μg g(-1) dry wt.).

Influence of phosphorus vapor ambient for InGaAsP growth on GaAs substrate

For visible-light-emitting laser diodes, InGaAsP double heterostructures have been grown on GaAs substrates using liquid-phase epitaxy. As the growth temperature is as high as about 780 °C, a large amount of phosphorus evaporates from the solutions for the cladding layers during the growth process. The phosphorus vapor disturbs the solution composition for the active layer, so that very thin and uniform active layers cannot be obtained. By using In-P-Sn solution and supplying the phosphorus partial pressure around the graphite boat, the influence of phosphorus vapor ambient for InGaAsP (λPL=805 nm) growth is confirmed. When the phosphorus partial pressure increases, the surface of epitaxial layer becomes rough and the substrate is partly etched back. From x-ray diffraction and photoluminescence spectral measurements, the composition of the grown layer is also found to be changed. As a result of increasing the flow rate of H2 gas in order to protect the solution for the active layer from phosphorus contamination, the double heterostructure wafers with the high-quality active layer can be obtained reproducibly. Thus, pulsed lasing operation at room temperature has been achieved. The lasing wavelength is 816 nm and the threshold current density is ∼4.6 kA/cm2.

Fabrication methods for InGaAsP/GaAs visible laser structure with AlGaAs burying layers grown by liquid-phase epitaxy

Liquid-phase-epitaxial (LPE) growth of AlGaAs layers has been used in fabricating InGaAsP buried heterostructure visible lasers on GaAs substrate. InGaAsP/InGaAsP double heterostructure wafers were grown on the p-type GaAs substrates by means of the melt-back method prior to the LPE growth for eliminating phosphorus contamination. An SiO2 film mask was deposited on the epitaxial wafer surface by the rf sputtering, and photoetched with stripes of 7–10 μm width in the 〈110〉 direction. After etching to the first p-InGaAsP cladding layer with a 3% Br-methanol solution, the second LPE growth of n-AlGaAs and p-GaAs layers was carried out. The InGaAsP active region is entirely surrounded by the InGaAsP cladding layers and the AlGaAs burying layer, therefore, it becomes possible to provide both lateral and vertical carrier and optical confinements. I-L characteristics were measured at room temperature under pulsed operation, but the lasing action was not obtained. The peak wavelength of the electroluminescence was 785 nm. The transverse mode behavior was analyzed by means of the effective refractive index approximation. And it seemed that this buried heterostructure is suitable for the transverse mode control of InGaAsP visible laser diodes.

DONOR BEHAVIOR IN INDIUM-ALLOYED SILICON

The anomalous doping behavior of Si regrown from In solution was studied by (1) Schottky barrier evaluation of conductivity type, (2) electron microprobe analysis for phosphorus, and (3) channeling effect measurements for interstitial In. The latter showed In present at ∼ 1019 cm−3, but not occupying a regular substitutional or interstitial position. A correlation was found in the first two measurements between phosphorus contamination and n-type conductivity. When the In was contacted only by quartz freshly etched in HF, the n-type behavior and phosphorus contamination disappeared. The anomalous doping behavior is most likely due to phosphorus inpurity picked up by the In.