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This experiment investigated bacterial transport from land-applied dairy shed effluent (DSE), via field lysimeter studies, using 2 contrasting irrigation methods. Transient water flow and bacterial transport were studied, and the factors controlling faecal coliform (FC) transport are discussed. Two trials (Trial 1, summer; Trial 2, autumn) were carried out, using 6 undisturbed soil monolith lysimeters, 500 mm diameter by 700 mm deep, with a free-draining, Templeton fine sandy loam. DSE with inert chemical tracers was applied at the start of both trials using the same method, followed with repeated 14-day cycles of either flood or spray irrigation of water. A bacterial tracer, antibiotic-resistant faecal coliform, was added to the DSE in Trial 2 only, to distinguish applied FC from external or resident FC. Leachates were collected after each water application (or heavy rainfall when applicable) for enumeration of FC and measurement of tracers. All lysimeters were instrumented for monitoring volumetric water content, matric potential, and soil temperature at 4 depths (100, 250, 450, and 600mm). The results showed that bacteria could readily penetrate through 700-mm-deep soil columns, when facilitated by water flow. The highest post-water irrigation concentration was 3.4 x [10.sup.3] cfu/100mL under flood irrigation, which resulted in more bacterial and [Br.sup.-] leaching than spray irrigation. Trial 2 (autumn) results also showed significant differences between irrigation treatments in lysimeters sharing similar drainage class (moderate or moderately rapid), flood irrigation again gave more bacterial and tracer ([Cl.sup.-]) leaching. In the summer trial, FC in leachate as high as 1.4 x [10.sup.6] cfu/100 mL, similar to the concentration of DSE, was detected in one lysimeter that had a higher clay content in the topsoil immediately after DSE application, and before any water irrigation. This indicates that applied DSE leached through preferential flow paths without any dilution. Bacterial concentration in the leachate was positively correlated with both volumetric water content and water potential, and sometimes drainage rate. Greater bacterial leaching was found in the lysimeter with rapid whole-column effective hydraulic conductivity, [K.sub.eff], for both flood and spray treatments. Occasionally, the effect of Kerr on water movement and bacterial transport overrode the effect of irrigation. The 'seasonal condition' of the soil (including variation in initial water content) also influenced bacterial leaching, with less risk of leaching in autumn than in summer. These findings contribute to our increased understanding of bacterial transport processes on the field scale. Additional keywords: bacterial transport, macropore, soil water content, drainage rate, irrigation, soil properties, seasonal variation., Introduction Land application of agricultural and industrial wastes has become increasingly popular, to promote nutrient recycling and environmental protection, with soil functioning as a barrier between wastes and groundwater. Dairy [...]

Bacterial transport in unsaturated soils is much less well understood than in saturated conditions, especially for intact soils. This paper aims to investigate the fate and transport of bacteria in intact soils with different water saturations, and particularly the effect of low suction (and hence removal of water flow in the largest macropores). An intact soil column (0.50 m diameter by 0.70 m depth) with a tension infiltrometer was used to investigate the transport and deposition of Bacillus subtilis endospores (i.e. dormant and persistent bacteria) during saturated and unsaturated flows. Soil porosity and pore size distribution were measured. Porosity decreased with depth and macropores were concentrated in the topsoil. Three tensiometers and a temperature sensor were installed along the soil column to monitor matric suction and temperature. Breakthrough curves for bacteria and chemical tracer [Br.sup.-] at 0 and 0.5 kPa suction were obtained during the 3-month leaching experiment. Bacterial breakthrough occurred earlier than the inert chemical tracer, which is consistent with effects of pore size exclusion. Also, saturated flow gave a significantly higher concentration and recovery ratio of leached bacteria, i.e. 51% v. 0.88%. Recovery of [Br.sup.-] in leachate at both suctions reached >85%. The column was destructively sampled for deposited endospores at the completion of leaching. Bacterial deposition was concentrated in the top 0.10 m, then decreased abruptly and was relatively constant with column depth, although showing some irregularity at the bottom of the column. Additional keywords: unsaturated intact soil, tension infiltrometer, pore size exclusion, air-water interface, film straining., Introduction Study of microbial transport through soils is of great importance in environmental, agronomic, and public health sciences. Concerns about water-borne infectious diseases have triggered research into the fate and [...]

Abstract A field study was conducted to characterize the transport of rhodamine WT dye and endospores of the bacterium Bacillus subtilis through preferential flowpaths in an alluvial gravel aquifer using [...]

The article offers information on procedure itself is not technically difficult and could simply be thought of as an extended thoracostomy. Topics include the blunt chest trauma with ultrasound evidence of tamponade physiology with cardiac arrest and evidence of cardiac activity, and the strong clinical suspicion of cardiac tamponade in the setting of chest trauma with systolic blood pressure.

The article presents questions and answers related to large-caliber central access via the subclavian vein, including situations that require inserting a large-caliber central venous line, patient positioning and the benefits of an ultrasound-guided internal jugular or femoral line.

Analyzes the transport of rhodamine WT dye and Bacillus subtilis through an alluvial gravel aquifer. Comparison of rhodamine WT's behavior to chloride in the field; Comparison of velocities; Importance of convection for B. subtilis endospores.

Readers responses to the challenges of becoming combination primary care provider and subspecialist, if the Extension for Community Healthcare Outcomes (ECHO) becomes a new paradigm for additional locations and diseases, are presented.