Efficacy of Vegetated Buffers in Preventing Transport of Fecal Coliform Bacteria from Pasturelands

An experimental study was conducted in Tillamook, Oregon, USA, to quantify the effectiveness of edge-of-field vegetated buffers for reducing transport of fecal coliform bacteria (FCB) from agricultural fields amended with dairy cow manure. Installation of vegetated buffers on loamy soils dramatically reduced the bacterial contamination of runoff water from manure-treated pasturelands, but the size of the vegetated buffer was not an important determinant of bacterial removal efficiency. Only 10% of the runoff samples collected from treatment cells having vegetated buffers exhibited FCB concentrations >200 colony forming units (cfu)/100 mL (a common water quality standard value), and the median concentration for all cells containing vegetated buffers was only 6 cfu/100 mL. The presence of a vegetated buffer of any size, from 1 to 25 m, generally reduced the median FCB concentration in runoff by more than 99%. Results for FCB load calculations were similar. Our results suggest that where substantial FCB contamination of runoff occurs from manure-treated pasturelands, it might be disproportionately associated with specific field or management conditions, such as the presence of soils that exhibit low water infiltration and generate larger volumes of runoff or the absence of a vegetated buffer. Buffer size regulations that do not consider such differences might not be efficient or effective in reducing bacterial contamination of runoff.     

Uncertainty Models for Estimates of Physical Characteristics of River Segments Over Large Areas

Spatially comprehensive estimates of the physical characteristics of river segments over large areas are required in many large‐scale analyses of river systems and for the management of multiple basins. Remote sensing and modeling are often used to estimate river characteristics over large areas, but the uncertainties associated with these estimates and their dependence on the physical characteristics of the segments and their catchments are seldom quantified. Using test data with varying degrees of independence, we derived analytical models of the uncertainty associated with estimates of upstream catchment area (CA), segment slope, and mean annual discharge for all river segments of a digital representation of the hydrographic network of France. Although there were strong relationships between our test data and estimates at the scale of France, there were also large relative local uncertainties, which varied with the physical characteristics of the segments and their catchments. Discharge and CA were relatively uncertain where discharge was low and catchments were small. Discharge uncertainty also increased in catchments with large rainfall events and low minimum temperature. The uncertainty of segment slope was strongly related to segment length. Our uncertainty models were consistent across large regions of France, suggesting some degree of generality. Their analytical formulation should facilitate their use in large‐scale ecological studies and simulation models.     

The relationship between sustainable development and resource use from a geographic perspective

Geography provides the basic building blocks for the study of resource use and sustainable development, inasmuch as it categorizes the human environment. Within the environment are resources that are needed for the survival of society. As resources are largely limited and finite, humans as agents of change must employ techniques that allow an efficient and lasting use of the available resources in their environment. This paper discusses the nexus between geography, resource exploitation, use, and sustainable development. It also discusses the characteristics, types, and classification of resources, development and sustainable development as well as the challenges and strategies for attaining sustainable development, particularly in developing countries.     

Arizona Hazardous Air Pollutants Monitoring Program

ABSTRACT

In order to evaluate the existing risk to public health in Arizona related to hazardous air pollution, ambient air monitoring for selected hazardous air pollutants (HAPs) was carried out in 1994-1996 in several representative urban and rural areas of Arizona. A wide range of organic HAPs was monitored, requiring a variety of sampling and analysis methods. Stainless steel SUMMA canisters were used for collection of volatile hydrocarbons and halocarbons, which were analyzed by capillary gas chromatography with flame ionization and electron capture detection (GC-FID/ECD). Carbonyl compounds were collected using 2,4-dinitrophenylhydrazine-impregnated cartridges and analyzed by high performance liquid chromatog-raphy with ultraviolet detection. Semi-volatile and non-volatile polycyclic aromatic compounds were collected using a sampling train consisting of a filter followed by a PUF/XAD-4/PUF sandwich cartridge. Following extraction, samples were analyzed by capillary GC with mass spectrometric detection (GC-MS). Database software was developed for data processing and reporting functions. This paper describes the sampling strategy and the sampling and analysis methods employed in the monitoring program and presents a summary of all the results obtained during the duration of the sampling program.     

Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem.

Every winter, government agencies feed approximately 6000 metric tons (6 x 10(6) kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed these possibilities using snowpack and feeding data from 1952 to 2006 and disease testing data from 1993 to 2006. Brucellosis seroprevalence was strongly correlated with the timing of the feeding season. Longer feeding seasons were associated with higher seroprevalence, but elk population size and density had only minor effects. In other words, the duration of host aggregation and whether it coincided with peak transmission periods was more important than just the host population size. Accurate modeling of disease transmission depends upon incorporating information on how host contact rates fluctuate over time relative to peak transmission periods. We also found that supplemental feeding seasons lasted longer during years with deeper snowpack. Therefore, milder winters and/or management strategies that reduce the length of the feeding season may reduce the seroprevalence of brucellosis in the elk populations of the southern GYE.     

Rapid and radical amniodrainage in the treatment of severe twin–twin transfusion syndrome†

We have evaluated the role of a rapid and radical method of amniodrainage in the treatment of severe twin–twin transfusion. The outcome of 15 patients with severe twin–twin transfusion for which a amniodrainage was performed by means of a vacuum bottle system was compared with the outcome of 15 patients with a similar condition, matched for gestational age at the time of the initial procedure and drained using a standard procedure. In the study group the amniodrainage ended when no amniotic fluid could be aspirated, whereas the women in the standard group were drained with a syringe system and the fluid was removed until the deepest amniotic fluid pool was <8 cm. At the initial procedure, the mean volume of amniotic fluid drained was significantly (p<0.05) higher (3252 vs 2153 ml) and the length of the procedure significantly (p<0.001) shorter (21 vs 41 min) in the study group than in the standard group. The mean post-procedure amniotic fluid index was significantly (p<0.001) smaller (2.9 vs 7.7 cm) after radical amniodrainage than after the standard amniodrainage. The mean number of procedures was significantly (p<0.001) lower (1.5 vs 5.6) in the study group compared to the standard group. In the study group the mean placental thickness increased significantly (p<0.001) from 9 mm before the procedure to 49 mm after, and the overall perinatal survival rate was 80% and the proportion of pregnancies with at least one survivor was 93%. The present data indicate that early, rapid and radical amniodrainage is an effective and low-cost therapy for severe twin–twin transfusion syndrome. Compared to the standard amniodrainage technique it also appears to reduce the need for multiple procedures. Copyright © 2001 John Wiley & Sons, Ltd.