ABSTRACT Knowledge of phosphorus (P) species in P‐rich soils is useful for assessing P mobility and potential transfer to ground water surface waters. Soil was studied using synchrotron X‐ray absorption near‐edge structure (XANES) spectroscopy (a nondestructive chemical‐speciation technique) sequential chemical fractionation. The objective determine the speciation long‐term‐fertilized, differing pH, clay, organic matter contents. Samples three slightly acidic (pH 5.5–6.2) two alkaline...

Abstract This paper briefly reviews the existing literature and uses evidence from three studies to demonstrate occurrence of preferential pathways P transport through soil. Studies conducted in St. Lawrence lowlands, Canada, indicated that particulate (PP‐i.e., >0.45 µm) main fraction total (TP) tile‐drainage water generated by storm events after periods low rainfall. In remainder year, concentration TP forms were related soil texture, primary tillage intensity frequency, showed wide...

Vacuum samples were collected from 1025 randomly selected urban Canadian homes to investigate bioaccessible Pb (PbS) concentrations in settled house dust. Results indicate a polymodal frequency distribution, consisting of three lognormally distributed subpopulations defined as "urban background" (geomean 58 μg g–1), "elevated" 447 and "anomalous" 1730 g–1). Dust PbS 924 (90%) fall into the category. The elevated anomalous predominantly consist older located central core areas cities....

Many agricultural fields contain excessive labile soil P in regard to crop needs. Its environmental fate must be assessed. The concept of saturation degree is meaningful as it describes the portion binding sites already covered with P, and indicates potential desorbability P. first objective this study was review different indices that have been proposed estimate relationships between solubility. second discuss their suitability indicators for management province Québec, Canada. In...

Abstract In most mineral soils, P leaching is rarely viewed as an important environmental issue. However, accumulation and decreased sorption capacities in surface horizons of long‐term fertilized soils may increase downward movement. The objective this study was to measure the concentration characterize forms drainage waters from nine soil series widely differing clay content. Twenty‐seven sites were sampled 1994 1995 intensively cropped area province Quebec, Canada. Drainage characterized...

The solubility of inorganic phosphorus in soils is regulated by surface-adsorbed phosphate or minerals.The objective this study was to determine whether different species relevance showed distinguishing XAFS spectral features.Phosphorus K-XANES spectra for Fe-phosphates were characterized a unique pre-edge feature near -3 eV (relative energy) that increased intensity with increasing mineral crystallinity and very weak adsorbed on goethite.Spectra Ca-phosphates soil sample exhibited distinct...

Abstract The objective of this work was to study the impact animal density on P status in soils from Beaurivage River Watershed, Quebec, Canada. Twenty‐five samples A, B, and C horizons five most representative soil series were taken sites under forest, hay fields dairy farms, farms with a known surplus on‐farm manure N (SN). Profiles characterized for water‐soluble (P w ), Mehlich‐3 extractable (M3P), fractions. 3.6 times larger agricultural than forest A horizon. Excessive amounts 66.5 mg...

Quantitative application of x‐ray absorption near edge structure (XANES) spectroscopy to soils and other geochemical systems requires a determination the proportions multiple chemical species that contribute measured spectrum. Two common approaches fitting XANES spectra are spectral deconvolution least‐squares linear combination (LCF). The objective this research was evaluate principal component analysis (PCA) coupled with target transformation model S K‐XANES humic acid samples, compare...

Characterizing the inorganic phase of biochar, beyond determining element concentration, is needed for appropriate application these materials because mineral forms also influence availability and behavior. Inorganics in 13 biochars (produced from Poultry litter, switchgrass, different types wood) were characterized by proximate analysis, chemical powder X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive (SEM-EDX) spectroscopy. Principal component analysis (PCA) was...

Resuspension of road dust is a major source airborne particulate matter (PM) in urban environments. Inhalation ultrafine particles (UFP; < 0.1 μm) represents health concern due to their ability reach the alveoli and be translocated into blood stream. It therefore important characterize chemical properties UFPs associated with vehicle emissions. We investigated capability Single-Particle ICP-MS (SP-ICP-MS) quantify key metal(loid)s nanoparticles (NPs; isolated from collected Toronto, Canada....

Iron‐ and Al‐(hydr)oxide minerals are important sorbents for retaining PO 4 in soils. Our objective was to determine the distribution of adsorbed between ferrihydrite boehmite aqueous mixtures these minerals. Phosphate suspensions up maximum concentrations 1860, 850, 1420 mmol kg −1 ferrihydrite, boehmite, 1:1 (by mass) at pH 6. The solids were analyzed as moist pastes using P K‐XANES (X‐ray absorption near edge structure) spectroscopy. adsorption isotherm mixed‐mineral could essentially be...

In watersheds with a high density of animal production, the land application large amounts manure has led to P accumulation in soils, thereby increasing risk leaching. The objective this study was characterize sorption-desorption kinetics soil under contrasting uses. A, B, and C horizons Typic Humaquept were sampled from forest (F) hay fields farms no surplus (D) or known (SN). Leaching experiments, using 0.01 M KCl solution containing 5 mg L−1 for sorption phase P-free electrolyte...

ABSTRACT This study examines factors affecting oral bioaccessibility of metals in household dust, particular metal speciation, organic carbon content, and particle size, with the goal addressing risk assessment information requirements. Investigation copper (Cu) zinc (Zn) speciation two size fractions dust (< 36 μ m 80–150 m) using synchrotron X-ray absorption spectroscopy (XAS) indicates that are bound to different components dust: Cu is predominately associated phase while Zn mineral...

Physical chemical characterization of nanomaterials is critical to assessing quality control during production, evaluating the impact material properties on human health and environment, developing regulatory frameworks for their use. We have investigated a set 29 from four metal oxide families (aluminum, copper, titanium zinc) with focus measurands that are important basic dry determination dose metrics nanotoxicology. These include crystalline phase crystallite size, measured by powder...

X-ray absorption fine-structure (XAFS) spectroscopy, micro-X-ray fluorescence (μXRF), and diffraction (μXRD) were used to determine the speciation of Pb in house dust samples from four Canadian urban homes having elevated concentrations (>1000 mg kg–1). Linear combination fitting XAFS data, supported by μXRF μXRD, shows that is complexed a variety molecular environments, associated with both inorganic organic fractions samples. The species lead identified as follows: metal, carbonate,...

Toxicological effects of metal-oxide-engineered nanomaterials (ENMs) are closely related to their distinct physical-chemical properties, especially solubility and surface reactivity. The present study used five metal-oxide ENMs (ZnO, MnO2, CeO2, Al2O3, Fe2O3) investigate how various biologically relevant media influenced dissolution behaviour. In both water cell culture medium (DMEM), the were more soluble than bulk analogues, with exception that bulk-MnO2 was slightly in nano-MnO2 Fe2O3...

Redox potential (E H ) measurement is a reading of voltage difference between working electrode such as Pt and reference inserted into the soil or various substrates. This study was conducted to develop method for continuous, autonomous, multiple E measurements using microelectrodes connected data logger. A preliminary field experiment carried out assess long‐term viability installed in situ. second laboratory test an interface designed allow stabilization measurements. The showed reliable...

The P saturation degree of agricultural, neutral to slightly alkaline soils in areas where fertilization is mainly inorganic relatively unknown. objective this study was determine the status whole profile 27 intensively cropped from an area receiving fertilizers, St. Lawrence lowlands province Quebec, Canada, and compare their a very different agrosystem with high animal density Appalachians. A, B, C horizons nine soil series (three sites per series) showing gradient clay content were...

Quantitative application of x-ray absorption near edge structure (XANES) spectroscopy to soils and other geochemical systems requires a determination the proportions multiple chemical species that contribute measured spectrum. Two common approaches fitting XANES spectra are spectral deconvolution least-squares linear combination (LCF). The objective this research was evaluate principal component analysis (PCA) coupled with target transformation model S K-XANES humic acid samples, compare...

More than 80 years of silver mining in the Cobalt area (Ontario, Canada) has led to widespread contamination water with arsenic. The objective this study was determine impact changes redox conditions on stability As samples collected from a tailings wetland historic camp. Dissolved metal concentrations were monitored while (∼1300 mg kg-1, pH 7.4) subjected 30 days reduction. Reoxidation accomplished by air drying. oxidation states original, reduced, and reoxidized determined using X-ray...

Road dust is an important source of resuspended particulate matter (PM) but information lacking on the chemical composition ultrafine particle fraction (UFP; &lt;0.1 µm). This study investigated metal concentrations in UFP isolated from “dust box” sweepings collected by City Toronto, Canada, using regenerative-air-street sweepers. Dust box samples expressway, arterial and local roads were aerosolized laboratory separated into thirteen size fractions ranging 10 nm to µm (PM10). The accounted...