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.     

Degradation of octylphenol and nonylphenol by ozone - part II: indirect reaction

The indirect reaction of octylphenol (OP) and nonylphenol (NP) with hydroxyl radicals (*OH) during ozonation was investigated at pH values ranging from 6 to 9. A parameter Rct, representing the ratio of the *OH-exposure to the ozone-exposure, was measured using a method involving a low concentration of p-chlorobenzoic acid as a *OH-probe compound during the ozonation. By assuming that Rct is a constant value at a given pH, the second order rate constants of the alkylphenol reaction with hydroxyl radicals were determined as 1.4(+/-0.2) x 10(10) and 1.1(+/-0.2) x 10(10) M(-1) s(-1) for OP and NP, respectively. The proportions of each alkylphenol degraded by direct molecular ozone reaction and indirect hydroxyl radical reaction were predicted at different pH values. The contribution of indirect *OH reactions with each AP was found to represent over 50% of the total degradation for pH approximately 7, and the contribution increases substantially with pH>7.     

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.     

Evaluating the risks of methyl tertiary butyl ether (MTBE) pollution of urban groundwater

MTBE, a fuel oxygenate added to gasoline in parts of the USA, appears to have imposed significant adverse impacts on groundwater. In the UK, the impacts of MTBE are not well known in part because insufficient data has been presented to allow an accurate assessment. With the recognition of urban groundwater as a potentially valuable resource due to the growing pressure on rural groundwater, there is need for pollution risks to urban groundwater to be evaluated for contaminants such as MTBE. This paper presents the application of a risk-based water management tool called Borehole Optimisation System (BOS) in the evaluation of the risk of MTBE to urban groundwater at city scale using Nottingham city as our case study. The risk model was validated by comparison of its predictions with observations of MTBE detections for about 1100 boreholes in England and Wales. The output of the risk analysis was the production of a map showing the predicted MTBE concentration at all locations in the city. The results indicate that MTBE does not currently pose a major risk to urban groundwater although there may be a potential risk to groundwater in the southern part of the city where most industries are concentrated.     

Climate change and national crop wild relative conservation planning

Climate change is likely to be one of the most important factors affecting our future food security. To mitigate negative impacts, we will require our crops to be more genetically diverse. Such diversity is available in crop wild relatives (CWRs), the wild taxa relatively closely related to crops and from which diverse traits can be transferred to the crop. Conservation of such genetic resources resides within the nation where they are found; therefore, national-level conservation recommendations are fundamental to global food security. We investigate the potential impact of climate change on CWR richness in Norway. The consequences of a 1.5 and 3.0 °C temperature rise were studied for the years 2030, 2050, 2070, 2080 and then compared to the present climate. The results indicate a pattern of shifting CWR richness from the south to the north, with increases in taxa turnover and in the numbers of threatened taxa. Recommendations for in situ and ex situ conservation actions over the short and long term for the priority CWRs in Norway are presented. The methods and recommendations developed here can be applied within other nations and at regional and global levels to improve the effectiveness of conservation actions and help ensure global food security.     

Atmospheric Chemistry of Chlorinated Phenols

The quantum yields for the photodegradation of a series of chlorophenols have been used to estimate their rates of solar photodegradation In the atmosphere. The photochemical rates have been compared with the calculated rates of attack by atmospheric hydroxyl radicals. These two processes are complementary, with photolysis being faster for pentachlorophenol, and OH attack being faster for monochlorinated phenols. As a result, it is predicted that most chlorophenol congeners will have quite similar atmospheric half-lives.     

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.     

Mechanosensitivity in the model sea anemone <Emphasis Type="Italic">Nematostella vectensis</Emphasis>

Tentacles of the sea anemone, Nematostella vectensis, are covered with hair bundles. Hair bundles were deflected by water jets to test whether they are mechanoreceptors. Electrophysiological recordings confirm that deflections of hair bundles induce transients in membrane current. In a different species of anemone, hair bundle mechanoreceptors are known to change shape and responsiveness according to the activity of chemoreceptors that bind prey-derived compounds including N-acetylated sugars. In Nematostella, hair bundles significantly elongate upon exposure to NANA, an N-acetylated sugar. Based on a bioassay in which discharged nematocysts are counted in gelatin-coated test probes touched to tentacles, we find that NANA shifts vibration dependent discharge of basitrich nematocysts to lower frequencies overlapping those produced during swimming by known prey including planktonic crustaceans. Furthermore, we find for the first time that vibration detection extends at least 2.5 cm beyond the tentacle tips. Thus, Nematostella likely employs its hair bundles to detect swimming movements of nearby prey.