Influences of sediment properties and macrophytes on phosphorous speciation in the intertidal marsh.

Phosphorus (P) in wetlands is mainly bound to sediment in various species, which is essential to predict water column P levels. The purpose of this work is to understand the influences of sediment properties and vegetation types on P speciation. Sediments under four vegetation types in the tidal flat and offshore sandbar in Hangzhou Bay of China were collected seasonally. The rank order of P species in sediment based on concentration was exchangeable P (Exch-P) < iron/aluminum-bound P (Fe/Al-P) < organic P (Org-P) < calcium-bound P (Ca-P). Sediment total phosphorus (TP) and Fe/Al-P concentrations were lower in offshore sandbar than those of tidal flat, reflecting effects of anthropogenic contamination in the latter. Sediment particle size distribution strongly affected P speciation, as indicated by a significant correlation between them. Total phosphorus and Org-P concentrations in vegetated sediments were higher than those of bare mudflat. Additionally, there was a significant negative correlation between Ca-P and Org-P, and Fe/Al-P, indicating the presence of vegetation which may result in P speciation by converting Ca-P to soluble and active P and higher Org-P. Overall, sediment particle size distribution is the most fundamental physical property that affects P speciation, and vegetation types are important factors that influence Org-P concentration.

Species of phosphorus in the extracellular polymeric substances of EBPR sludge.

In this study, the species of extracellular phosphorus and their transformation during extracellular polymeric substances (EPS) extraction were explored by using (31)P nuclear magnetic resonance spectroscopy. Results show that the extraction methods had a substantial influence on the phosphorus species in the extracted EPS. Cation exchange resin method was more appropriate for extracting EPS from the enhanced biological phosphorus removal (EBPR) sludge. Orthophosphate, pyrophosphate and polyphosphate were the main species of phosphorus found to be present in the EPS, which together accounted for about 6.6-10.5% of the total phosphorus in the EBPR sludge. The high percentage of extracellular phosphorus and their diverse species might reveal a new insight into the characteristics of the phosphorus in EPS in EBPR system.

Classification of chronic kidney disease biomarkers to predict coronary artery calcium.

BACKGROUND/AIMS: The link between CKD and CAC has been mostly established by studies of patients who have abnormally high phosphorus levels and advanced CKD or end-stage renal disease. The aim of this study was to examine if there are distinct trajectory classes of serum phosphorus (controlling for eGFR) that are associated CAC in a relatively healthy, community sample. METHODS: Phosphorus and eGFR were classified as a combined biomarker variable with 4 trajectory classes by growth mixture modeling. This classification variable was subsequently used to predict CAC as both a binary (i.e., onset) and continuous (i.e., accumulation) outcome using a two-part growth model. RESULTS: Membership in one class of phosphorus trajectory versus the next lowest level was associated with a 97.9 Agatston unit increase in CAC (p <.001). The magnitude of this finding is similar in size as some primary risk factors for cardiovascular disease, including a 55.3 Agatston unit (p <.001) increase associated with age, and a--75.1 Agatston unit (p <.001) decrease associated with female gender. CONCLUSIONS: Classification of phosphorus trajectories provides further definition for prediction of CAC within the conventional 'normal' range. Classifying trajectories may help determine clinically-relevant thresholds for interventions aimed at phosphorus reduction.

Control of red phosphorus, white phosphorus and hypophosphorous acid (and its salts) as list I chemicals; exclusions and waivers. Final rule.

On October 17, 2001, DEA published a Final Rulemaking (66 FR 52670) in which DEA added red phosphorus, white phosphorus (also known as yellow phosphorus) and hypophosphorous acid (and its salts) as List I chemicals. This action was taken because of the use and importance of these chemicals in the illicit manufacture of methamphetamine (a Schedule II controlled substance). As List I chemicals, handlers of these materials became subject to Controlled Substances Act (CSA) chemical regulatory controls including registration, recordkeeping, reporting, and import/export requirements. DEA had determined that these controls are necessary to prevent the diversion of these chemicals to clandestine drug laboratories. In order to provide flexibility for legitimate businesses, the October 17, 2001 rule established, on an interim basis, specific exclusions and waivers for chemical handlers engaged in certain activities. DEA has completed its review of comments pertaining to these interim provisions. This rulemaking finalizes these exclusions and waivers related to the handling of the listed chemicals red phosphorus, white phosphorus, and hypophosphorous acid (and its salts).