Trapping Phosphorus in Runoff with a Phosphorus Removal Structure

Reduction of phosphorus (P) inputs to surface waters may decrease eutrophication. Some researchers have proposed fi ltering dissolved P in runoff with P-sorptive byproducts in structures placed in hydrologically active areas with high soil P concentrations. Th e objectives of this study were to construct and monitor a P removal structure in a suburban watershed and test the ability of empirically developed fl ow-through equations to predict structure performance. Steel slag was used as the P sorption material in the P removal structure. Water samples were collected before and after the structure using automatic samples and analyzed for total dissolved P. During the fi rst 5 mo of structure operation, 25% of all dissolved P was removed from rainfall and irrigation events. Phosphorus was removed more effi ciently during low fl ow rate irrigation events with a high retention time than during high fl ow rate rainfall events with a low retention time. Th e six largest fl ow events occurred during storm fl ow and accounted for 75% of the P entering the structure and 54% of the P removed by the structure. Flow-through equations developed for predicting structure performance produced reasonable estimates of structure “lifetime” (16.8 mo). However, the equations overpredicted cumulative P removal. Th is was likely due to diff erences in pH, total Ca and Fe, and alkalinity between the slag used in the structure and the slag used for model development. Th is suggests the need for an overall model that can predict structure performance based on individual material properties

Trapping Phosphorus in Runoff with a Phosphorus Removal Structure

Reduction of phosphorus (P) inputs to surface waters may decrease eutrophication. Some researchers have proposed fi ltering dissolved P in runoff with P-sorptive byproducts in structures placed in hydrologically active areas with high soil P concentrations. Th e objectives of this study were to construct and monitor a P removal structure in a suburban watershed and test the ability of empirically developed fl ow-through equations to predict structure performance. Steel slag was used as the P sorption material in the P removal structure. Water samples were collected before and after the structure using automatic samples and analyzed for total dissolved P. During the fi rst 5 mo of structure operation, 25% of all dissolved P was removed from rainfall and irrigation events. Phosphorus was removed more effi ciently during low fl ow rate irrigation events with a high retention time than during high fl ow rate rainfall events with a low retention time. Th e six largest fl ow events occurred during storm fl ow and accounted for 75% of the P entering the structure and 54% of the P removed by the structure. Flow-through equations developed for predicting structure performance produced reasonable estimates of structure “lifetime” (16.8 mo). However, the equations overpredicted cumulative P removal. Th is was likely due to diff erences in pH, total Ca and Fe, and alkalinity between the slag used in the structure and the slag used for model development. Th is suggests the need for an overall model that can predict structure performance based on individual material properties

A Review of Dabigatran, an Oral Anticoagulant

Serious clinical complications associated with venous thrombotic embolism (VTE) necessitate prophylaxis in patient groups who are at high risk of VTE, specifically those recovering from orthopedic surgery with atrial fibrillation, with mechanical heart valves, at increased risk for stroke, or recovering post-MI. Currently, prophylaxis with warfarin, enoxaparin, or fondaparinux has been the standard of therapy, but these therapies each have their limitations. Dabigatran etexilate is an orally available pro-drug of dabigatran, a competitive, reversible, direct inhibitor thrombin (Factor lla). The agent is converted by esterases, and, thus, not associated with the complications of the CYP enzyme system. Dabigatran follows a linear dose-response curve simplifying dosing compared to other agents. In the BISTRO II study, a dose as low as 50 mg dabigatran was found to be non-inferior to the current standard of therapy of 40 mg enoxaparin, and BISTRO I and II, RE-NOVATE and RE-LY all found dabigatran was better or equivalent to warfarin therapy for post-hip and knee replacements. Dabigatran could be especially beneficial in patients who have a contraindication to warfarin, need long-term anticoagulation and require less patient monitoring. With FDA approval and release of this drug, time will provide safety and efficacy data to solidify dabigatran\u27s place in therapy along current anti-coagulation guidelines