Fate of pathogens in a simulated bioreduction system for livestock carcasses

The EU Animal By-Products Regulations generated the need for novel methods of storage and disposal of dead livestock. Bioreduction prior to rendering or incineration has been proposed as a practical and potentially cost-effective method; however, its biosecurity characteristics need to be elucidated. To address this, Salmonella enterica (serovars Senftenberg and Poona), Enterococcus faecalis, Campylobacter jejuni, Campylobacter coli and a lux-marked strain of Escherichia coli O157 were inoculated into laboratory-scale bioreduction vessels containing sheep carcass constituents. Numbers of all pathogens and the metabolic activity of E. coli O157 decreased significantly within the liquor waste over time, and only E. faecalis remained detectable after 3months. Only very low numbers of Salmonella spp. and E. faecalis were detected in bioaerosols, and only at initial stages of the trial. These results further indicate that bioreduction represents a suitable method of storing and reducing the volume of livestock carcasses prior to ultimate disposal.     

Effects of gaseous NH(3) and SO(2) on the concentration profiles of PCDD/F in flyash under post-combustion zone conditions

The influence of gaseous ammonia and sulphur dioxide on the formation of 2378-substituted PCDD/F on a reference flyash from a municipal waste incinerator has been investigated using a laboratory scale fixed-bed reactor. The reference flyash samples (BCR-490) was reacted under a simulated flue gas stream at temperatures of 225 and 375°C for 96h. The experiments were carried out in two series: first with simulated flue gas alone, and then with injection of NH(3) or SO(2) gas into the flue gas just before the reactor inlet. It was found that the injection of gaseous ammonia into the flue gas could decrease the concentration of both PCDD and PCDF by 34-75% from the solid phase and by 21-40% from the gas phase. Converting the results to I-TEQ values, it could reduce the total I-TEQ values of PCDD and PCDF in the sum of the flyash and exhaust flue gas by 42-75% and 24-57% respectively. The application of SO(2) led to 99% and 93% reductions in the PCDD and PCDF average congener concentrations, respectively in the solid phase. In the gas phase, the total reductions were 89% and 76% for PCDD and PCDF, respectively. Moreover, addition of SO(2) reduced the total I-TEQ value of PCDD and PCDF in the flyash and exhaust flue gas together by 60-86% and 72-82% respectively. Sulphur dioxide was more effective than ammonia in suppressing PCDD/F formation in flyash under the conditions investigated.     

The role of enforcement programs in increasing seat belt use

Seat belt laws by themselves led to increased belt use in the United States and Canada, but initial effects were limited. Canadian provincial officials launched highly publicized enforcement campaigns in the early 1980s that resulted in substantially increased belt use. Canadian-style enforcement programs subsequently were adopted in the United States, and the use of such programs has grown in recent years. Lessons from these efforts include the importance of police leadership, focused publicity about enforcement, and sustained rather than single-shot efforts. What is needed in the United States to achieve a national belt use rate of 90% or greater is widespread, methodical, and sustained application of enforcement programs augmented by creative publicity. Enhanced penalties-in particular drivers license points-likely will be needed to reach hard-core nonusers.     

Methods to reduce traffic crashes involving deer: what works and what does not

More than 1.5 million traffic crashes involving deer, producing at least $1.1 billion in vehicle damage and about 150 fatalities, are estimated to occur annually in the United States. Deer-related crashes are increasing as both deer populations and vehicular travel increase. Many methods have been used in attempts to reduce deer crashes, often with little scientific foundation and limited evaluation. This article summarizes the methods and reviews the evidence of their effectiveness and the situations in which each may be useful. The only widely accepted method with solid evidence of effectiveness is well-designed and maintained fencing, combined with underpasses or overpasses as appropriate. Herd reduction is controversial but can be effective. Deer whistles appear useless. Roadside reflectors appear to have little long-term effect, although additional well-designed evaluations are needed before firm conclusions can be drawn. Both temporary passive signs and active signs appear promising in specific situations, but considerable research is required to evaluate long-term driver response and to improve and test deer detection technology for active signs. Other methods using advanced technology require substantial additional research and evaluation.     

Phosphorus losses from grasslands fertilized with broiler litter: EPIC simulations

Broiler litter, a mixture of poultry excreta and bedding material, is commonly used to fertilize grasslands in the southeastern USA. Previous work has shown that under certain situations, application of broiler (Gallus gallus domesticus) litter to grasslands may lead to elevated levels of phosphorus (P) in surface runoff. The EPIC simulation model may be a useful tool to identify those situations. This work was conducted to evaluate EPIC's ability to simulate event and annual runoff volume and losses of dissolved reactive phosphorus (DRP) from tall fescue (Festuca arundinacea Schreb.)-bermudagrass [Cynodon dactylon (L.) Pers.] paddocks fertilized with broiler litter. The EPIC simulations of event runoff volume showed a trend toward underestimation, particularly for runoff events >30 mm. On an annual basis, EPIC also tended to underestimate runoff, especially at runoff volumes > 100 mm. Both event and annual runoff estimations were strongly associated with observed values, indicating that model calibration could improve the simulation of surface runoff volume. The relationship between simulated and observed values of DRP loss was relatively poor on an event basis (r=0.65), but was stronger (r=0.75) on an annual basis. In general, EPIC tended to underestimate annual DRP losses. This underestimation was apparently caused by the lack of an explicit mechanism to model broiler litter on the soil surface. These results suggested that additional work on the EPIC P submodel would be warranted to improve its simulation of surface application of broiler litter to grasslands.     

The GANE Roof Project: The impact of reduced N & S deposition and experimental warming in an acid grassland

A field-based system used to quantify the response of acid grassland to reduced atmospheric nitrogen and sulphur deposition, and to investigate the effects of elevated soil temperature on acid grassland development is described. The system is based on 12 retractable roofs, covering undisturbed experimental plots of acid grassland and three controls. Nine roofs are used to exclude natural precipitation and three roofs used to retain emitted IR radiation at night. An irrigation system has been developed to simulate natural precipitation, allowing for the application of specific treatment regimes of ambient, reduced nitrogen and reduced nitrogen/sulphur deposition beneath the nine rain exclusion plots. Plant, soil parameters, leachate chemistry and gaseous fluxes are being monitored and initial results on soil water chemistry are described. Warming appeared to enhance nitrate concentrations in soil water but this was not sustained beyond the first year of treatment. In contrast, the deposition reduction treatments decreased soil water nitrate concentrations within a few weeks of reducing deposition. This was not observed for other solutes such as sulphate or ammonium suggesting a more direct link between deposition of nitrate and leaching losses.     

FLUSHING CHARACTERISTICS OF A MISSISSIPPI DEAD-END CANAL SYSTEM1

ABSTRACT: A study of residential canal system on the Mississippi Gulf Coast and adjacent natural water bodies was conducted to determine the relationship in flushing characteristics between man-made and natural systems. The comparison was based on measurements of temperature, salinity, conductivity, coliform, pH, transparency, biological oxidation demand, dissolved oxygen, bathymetry, tides, water velocity, and Rhodamine dye concentrations. The results indicate that coliform bacteria increase with increasing distance of stations from St. Louis Bay and dissolved oxygen decreases in a similar manner. Biological oxidation demand was low at all stations; showing no differences between natural and man-made systems. The canal system Studied was shallower than adjacent water bodies and water velocities in the canal system are a function of tidal amplitude while velocities in the river are affected by both tides and runoff. The other parameters measured show little or no differences between natural and man-made systems, but reflect overall seasonal changes. Flushing rates between the residential canal systems and an adjacent natural system are equivalent on the basis of decline in dye concentrations measured over a five-day period.     

DRAWDOWN AT TIME-DEPENDENT FLOWRATE1

ABSTRACT: The exact solution for the drawdown in and around a well in a homogeneous, isotropic, and confined aquifer is presented if the well discharge is a function of time. The effect of the storage capacity of the well is also taken into consideration. Two types of flowrate functions are studied, namely linear and exponential functions, and the results are plotted in graphs.     

Zone planning régimes

Recent discussion of Enterprise Zones in England has been concerned with attributing development to the financial package of incentives operating, rather than the simplified planning régime, the author reconsiders the question of the significance of the new forms of planning procedure and suggests that, in the long term, the experiment will have lasting significance for the planning system itself.     

Study of total organic halogen as a means to detect groundwater contamination

Total organic halogen (TOX) was evaluated as a means to detect contamination of groundwater by halogenated organics. Groundwater samples from monitoring wells at 10 Canadian landfill sites were analyzed for carbon adsorbable TOX, total organic carbon and volatile organics. Low concentrations of TOX (range, ND-44; median 8 μg Cl L^?1) were found at nine sites, and elevated TOX levels (?2072 μg Cl L^?1) at the tenth site. This latter site was studied in greater detail, and TOX and GC-MS analyses were carried out for volatile, base neutral, and acid extractable fractions of the water in six monitoring wells at this site. The TOX and GC-MS techniques were found to provide complementary information. GC-MS analysis detected high concentrations of 1,2-dichloroethylene, trichloroethylene, toluene, and ethylbenzene in some of the wells. TOX measurements, however, indicated the presence of halogenated contaminants in the base-neutral and acid extractable fractions, which had not been detected by GC-MS.