Effect of varying the phosphorus content of dairy cow diets on losses of phosphorus in overland flow following surface applications of manure

The increasing use of concentrate feedstuffs within Northern Ireland dairy systems has resulted in significant farm gate phosphorus (P) surpluses, and these have contributed to increased soil P levels and risk of P loss to overland flow. However, the P content of feed concentrates can be lowered without compromising animal performance. This study focuses on P losses from grassland and evaluates how adjusting the P content of manure impacts on the P composition and concentration in overland flow. Dairy cows were offered diets containing 5.3 to 3.0 g P kg(-1) dry matter (DM) and produced manures with a range of P contents. Manure was applied at a rate of 50 m3 ha(-1) to 0.5-m2 grassland plots, and simulated rainfall (40 mm h(-1)) was applied repeatedly 2, 9, 28, and 49 d after during the summer, winter, and spring. Decreasing the P content in the diet, from the highest to the lowest P treatment (43%), produced a proportionately greater reduction in manure TP content (63%), but reductions were not exclusively in the water-soluble fraction. Following surface applications of manure, P concentrations in overland flow increased in all seasons (P < or = 0.001), while the greatest impact of varying the manure P content was most evident during the first simulated overland flow event. When diet P content was reduced from 5.4 to 3.0 g P kg(-1) DM, a statistically significant reduction in runoff P concentration was observed in all seasons. Elevated P concentrations in overland flow were observed for 28 d in spring and 9 d in summer and winter. The large drop in P concentrations between simulated rainfall events on Day 2 and Day 9 suggests that increasing the time interval between manure application and the generation of overland flow has a greater impact on P losses than does varying the dietary P content.     

An observational case study of ozone and precursors inflow to South East England during an anticyclone

Summertime photochemical air pollution episodes within the United Kingdom have been proposed via modelling studies to be strongly influenced by regional scale inflow of air from the continental European boundary layer. We present a vertically resolved case study using measurements made from the NERC/Met Office BAe 146 research aircraft on 18th August 2005 over the South East of England and the North Sea during a weak anticyclone centred over Northern Europe. The vertical distribution of ozone, CO, NO(x), peroxyacetyl nitrate (PAN) and a wide range of both nonmethane hydrocarbons (NMHC) and oxygenated volatile organic compounds (OVOCs) were determined between 500 ft (approximately 152 m) and 7000 ft (approximately 2134 m) over the East Anglia coastline and 50 km inland. In excess of 80 ppbV ozone was observed within inflowing boundary layer air over the North Sea coast in a broad N-S sloping feature around 60 km wide. The inflowing feature of European origin was also observed further inland within the boundary layer albeit with lower, more variable, ozone mixing ratios. The increased variability in ozone over land was a product of titration by fresh surface emissions of NO via rapid upward transport in thermals, a hypothesis supported by the observed vertical wind speed component. Fast boundary layer mixing over land was further illustrated by a uniform distribution in reactive alkenes. A comparison between aircraft and surface O(3) UK AUN (Automatic Urban Network) measurements showed good agreement with the inland site, Sibton, but marked differences with the coastal monitoring site at Weybourne, potentially due to gradients established by ocean deposition in stably stratified marine air.     

The impacts of knowledge of the past on preferences for future landscape change

In this paper, we investigate whether people's knowledge of the past influences their preferences and values towards future landscape change. "Knowledge of the past" is one aspect of the information set held by individuals, and a well-established finding in economics is that changes in information can change preferences and values. The particular aspects of knowledge of the past we work with here are: (i) awareness of past landuse, as represented by woodland cover and (ii) awareness of differing and sometimes contradictory literary impressions of this past landscape. The case studies used here relate to prospective changes in woodland cover in two UK national parks, the Lake District and the Trossachs. We find that people who are made aware that the landscape has changed over time, or that perceptions of the landscape have changed over time, are more likely to favour changes to the current landscape (are less likely to favour the status quo). Knowledge of the past therefore seems to have an impact on preferences for future landscapes. We also investigate the impacts on preferences of how "special", how "wild" and how "worked in" people perceive the landscapes of these two national parks to be.     

Dilution-based emissions sampling from stationary sources: Part 1--Compact sampler methodology and performance

This paper presents the design and performance of a compact dilution sampler (CDS) for characterizing fine particle emissions from stationary sources. The sampler is described, along with the methodology adopted for its use. Dilution sampling has a number of advantages, including source emissions that are measured under conditions simulating stack gas entry and mixing in the ambient atmosphere. This is particularly important for characterizing the semivolatile species in effluents as a part of particulate emissions. The CDS characteristics and performance are given, along with sampling methodology. The CDS was compared with a reference dilution sampler. The results indicate that the two designs are comparable for tests on gas-fired units and a diesel electrical generator. The performance data indicate that lower detection limits can be achieved relative to current regulatory methods for particulate emissions. Test data for the fine particulate matter (PM2.5) emissions are provided for comparison with U.S. Environment Protection Agency (EPA) Conditional Test Method 040 for filterable particulate matter (FPM) and the EPA Method 202 for condensable particulate matter. This comparison showed important differences between methods, depending on whether a comparison is done between in situ FPM determinations or the sum of such values with condensable PM from liquid filled impingers chilled in an ice bath. These differences are interpretable in the light of semivolatile material present in the stack effluent and, in some cases, differences in detection and quantification limits. Determination of emissions from combustors using liquid fuels can be readily achieved using 1-hr sampling with the CDS. Emissions from gasfired combustors are very low, requiring careful attention to sample volumes. Sampling volumes corresponding with 6-hr operation were used for the combined mass and broad chemical speciation. Particular attention to dilution sampler operation with clean dilution air also is essential for gas-fired sources.     

Veterinary waste disposal: practice and policy in Durban, South Africa (2001-2003)

In South Africa, until recently, veterinary waste has not been included in definitions of health care waste, and so has been neglected as a contributor to the hazardous waste stream. Despite the application of, for example, the "Polluter Pays" principle in South African environmental legislation, to generators of waste, which would include veterinarians, there appears to be little awareness of and even less enforcement of the legislation in this regard. This paper reports on a 2001-2003 survey of management practices of the five waste contractors servicing just over half of the veterinarians in Durban, South Africa's second largest city. Some of their activities, when evaluated in terms of the legislation, guidelines and policies relating to waste handling and disposal, were found to be non-compliant. Since any discussion on waste management should take cognisance of waste from generation to final disposal, the responsibility of veterinarians as waste generators is also discussed in the light of the recent developments in health care waste management in South Africa. This study presents a review of past and current policies, legislation and guidelines that have application to veterinary waste. This is the first study to address veterinary waste disposal in any South African city.     

A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions

This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing N(E) equilibrium reactions and a set of reactive transport equations of M-N(E) kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions.     

The Gathering Storm: managing adaptation to environmental change in coastal communities and small islands

Small island communities are inherently coastal communities, sharing many of the attributes and challenges faced by cities, towns and villages situated on the shores of larger islands and continents. In the context of rapidly changing climates, all coastal communities are challenged by their exposure to changing sea levels, to increasingly frequent and severe storms, and to the cumulative effects of higher storm surges. Across the globe, small island developing states, and small islands in larger states, are part of a distinctive set of stakeholders threatened, not only by climate change but also by shifting social, economic, and cultural conditions. C-Change is a collaborative International Community–University Research Alliance (ICURA) project whose goal is to assist participating coastal communities in Canada and the Caribbean region to share experiences and tools that aid adaptation to changes in their physical environment, including sea-level rise and the increasing frequency of extreme weather events associated with climate change. C-Change researchers have been working with eight partner communities to identify threats, vulnerabilities, and risks, to improve understanding of the ramifications of climate change to local conditions and local assets, and to increase capacity for planning for adaptation to their changing world. This paper reports on the knowledge gained and shared and the challenges to date in this ongoing collaboration between science and society.