Phosphorus speciation in broiler litter and turkey manure produced from modified diets

Modifying poultry diets by reducing mineral P supplementation and/or adding phytase may change the chemical composition of P in manures and affect the mobility of P in manure-amended soils. We studied the speciation of P in manures produced by broiler chickens and turkeys from either normal diets, or diets with reduced amounts of non-phytate phosphorus (NPP) and/or phytase, using a combination of chemical fractionation and synchrotron X-ray absorption near edge structure (XANES) spectroscopy. All broiler litters were rich in dicalcium phosphate (65-76%), followed by aqueous phosphate (13-18%), and phytic acid (7-20%); however, no hydroxylapatite was observed. Similarly, normal turkey manure had 77% of P as dicalcium phosphate and had no hydroxylapatite, while turkey manure from diets that had reduced NPP and phytase contained equal proportions of dicalcium phosphate (33-45%) and hydroxylapatite (35-39%). This is attributed to the higher total Ca to P ratio (>2) in modified turkey manures that resulted in transformation of more soluble (dicalcium phosphate) to less soluble P compounds (hydroxylapatite). Chemical fractionation showed that H2O-extractable P was the predominant form in broiler litter (56-77%), whereas aqueous phosphate determined with XANES was <18% indicating that H2O probably dissolved mineral forms of P (e.g., dicalcium phosphate). Results show that HCl extraction primarily removed phytic acid from broiler litters and normal turkey manure, while it removed a mixture of hydroxylapatite and phytic acid from modified turkey manures. The combination of chemical fractionation and XANES provided information about the nature of P in these manures, which may help to devise best management practices for manure use.     

Diesel particulate matter exposure and risk control measures

This paper describes the environmental health problem of exposure to diesel particulate matter(DPM) in an underground mine in Western Australia.It contains recommendations for innovative equipment and management improvements in risk control for employees who work in underground mines and for companies who use machines that are powered by diesel fuel.     

INSTITUTIONALIZED INEFFICIENCY: THE UNFORTUNATE STRUCTURE OF COLORADO'S WATER RESOURCE MANAGEMENT SYSTEM1

ABSTRACT: This analysis identifies two basic structural features of Colorado's water management system which inhibit constructive reform and perpetuate inefficiencies in water use and distribution patterns. These features are: (1) the fragmentation of authority and influence over water, and (2) the estrangement of interest in reform from formal control over water policy. These interrelated features have continued to produce: sporadic, high conflict battles over proposed changes in the status quo; decision making which tends to exaggerate the importance of narrow, special interests while virtually ignoring legitimate interests of major sectors of the public; an inertia which discourages innovation; and an agglomeration of rules and water rights that are predicated on obsolete social and economic needs. Two radical proposals for reforming the state's water resource management system in order to overcome these problems and to enhance the probability that wise water policy will result are offered. These proposals are: (1) the abolition of the present system of water rights founded on the doctrine of prior appropriation, and (2) the consolidation of authority over water allocation in a single board of governors.     

Speciation and distribution of copper in a mining soil using multiple synchrotron-based bulk and microscopic techniques

Molecular-level understanding of soil Cu speciation and distribution assists in management of Cu contamination in mining sites. In this study, one soil sample, collected from a mining site contaminated since 1950s, was characterized complementarily by multiple synchrotron-based bulk and spatially resolved techniques for the speciation and distribution of Cu as well as other related elements (Fe, Ca, Mn, K, Al, and Si). Bulk X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that soil Cu was predominantly associated with Fe oxides instead of soil organic matter. This agreed with the closest association of Cu to Fe by microscopic X-ray fluorescence (U-XRF) and scanning transmission X-ray microscopy (STXM) nanoanalysis, along with the non-occurrence of photoreduction of soil Cu(II) by quick Cu L_3,2-edge XANES spectroscopy (Q-XANES) which often occurs when Cu organic complexes are present. Furthermore, bulk-EXAFS and STXM-coupled Fe L_3,2-edge nano-XANES analysis revealed soil Cu adsorbed primarily to Fe(III) oxides by inner-sphere complexation. Additionally, Cu K-edge μ-XANES, L_3,2-edge bulk-XANES, and successive Q-XANES results identified the presence of Cu₂S rather than radiation-damage artifacts dominant in certain microsites of the mining soil. This study demonstrates the great benefits in use of multiple combined synchrotron-based techniques for comprehensive understanding of Cu speciation in heterogeneous soil matrix, which facilitates our prediction of Cu reactivity and environmental fate in the mining site.