Peter J. Ashton

Responses of phytoplankton upon exposure to a mixture of acid mine drainage and high levels of nutrient pollution in Lake Loskop, South Africa

The relationships between water quality and the phytoplankton community within Lake Loskop were studied during the late summer and autumn of 2008 to evaluate the impacts of acid mine drainage and high nutrient concentrations. The higher concentrations of metal ions and sulphate had adverse effects on certain phytoplankton species in the inflowing riverine zone of Lake Loskop, in comparison to the reference site in the lacustrine zone of the lake, which was dominated by the larger and slower growing late summer species of Coelastrum reticulum Nägeli, Straurastrum anatinum Meyen ex Ralfs and Ceratium hirundinella Müller. The high nutrient concentrations (nitrogen: 17 mg l(-1) and orthophosphate: 0.7 mg l(-1)) during the mid-summer peak of the rainy season were associated with the development of a bloom of the cyanobacterium Microcystis. Water quality data associated with the development of the Microcystis bloom suggest that the aquatic system of Lake Loskop has now entered an alternate, hypertrophic regime. This change overshadowed the adverse effects of high concentrations of heavy metal ions and low pH. Throughout this study, the reference site in the lacustrine zone of Lake Loskop had lower concentrations of metal ions and sulphate, and higher pH values. The response of phytoplankton bioassays on integrated water samples from the different sampling sites did provide potential answers to the reasons for the absence of the algal group Chlorophyceae in the phytoplankton community structure in the riverine zone of the lake.

Towards a Model for Ecosystem Governance: An Integrated Water Resource Management Example

The concept of governance, and especially good governance, is pivotal to the achievement of Integrated Water Resource Management (IWRM). The concepts of governance used in much of the current literature on IWRM indicate that it is often used in a contradictory way and sometimes used interchangeably with the word government. This chapter proposes a Trialogue Model of governance that is structured around three groups of actors — government, society and science — and discusses the dynamic interactions between these groups. The interfaces between these three groups of actors, or actor-clusters, and the dynamics of their interactions, provide the basis for a critical assessment of governance as a concept. The chapter isolates four specific elements of scale that are relevant to governance: economic, political, administrative and international; as well as three structural aspects: mechanisms, processes and institutions. In addition, the chapter identifies four processes: articulating interests, exercising legal rights, discharging legal obligations and mediating disputes, and analyses the central role of norms and values in good governance. Finally, an analytical distinction is made between governance as a process and governance as a product, and a new definition of ecosystem governance is offered. Evidence is presented to demonstrate the highly dynamic nature of governance processes, with clear differences that distinguish mature democracies and fledgling democracies.

Bioaccumulation of aluminium and iron in the food chain of Lake Loskop, South Africa.

Concentrations of total aluminium (Al) and iron (Fe) were determined in Lake Loskop over a period of four months in 2009 in samples of phytobenthos, phytoplankton, macroinvertebrates, amphibians and fish. The highest concentrations of Al and Fe were measured in the filamentous algae Spirogyra fluviatilis (Hillse) and Spirogyra adanata (Kütz), (Al=18,997.5mgkg(-1) dry weight and Fe=22,054.2mgkg(-1) dry weight) in the riverine zone of the lake with a near-neutral water average pH of 7.3. However, a negative correlation exists between the Al and Fe concentrations measured in the filamentous algae in comparison with the corresponding concentrations of these elements in the water column of the riverine zone. The Al concentrations in the macroinvertebrate families collected ranged from 140.6 to 385.7mgkg(-1) dry weight, with the highest values measured for Al and Fe in the family Gomphidae (385.7 and 1710.0mgkg(-1) dry weight, respectively) in comparison to other macroinvertebrate families sampled. Al and Fe concentrations (2580 and 10,697mgkg(-1) dry weight) in the stomach contents of adult Oreochromis mossambicus fishes were much higher in comparison with adult Micropterus salmoides fishes (98.5 and 439.6mgkg(-1) dry weight), respectively. In all cases of dissected fish species either white or yellow body fat was observed, thus in none of the samples both type of body fats occurred simultaneously. The concentrations of total Al and Fe in the different organs of O. mossambicus were along a mean sequence of intestine>yellow body fat>brain>gills>liver>heart>white body fat, while the mean sequence of total Al and Fe in M. salmoides was: intestine>gills>liver>heart>brain>white body fat. From the levels of Al detected in the yellow body fat of the studied fish species O. mossambicus, we suggest that this phenomenon may be related to the feeding habits of this species. Furthermore, the intake of certain species of phytobenthos by O. mossambicus could have played a role in the bioaccumulation of Al in the food chain and the possible development of pansteatitis in predators at higher trophic levels.

Adapting to Change in Transboundary Rivers: An Analysis of Treaty Flexibility on the Orange-Senqu River Basin

Continuously changing patterns of water flow and utilization in the Orange-Senqu River basin hamper effective management of shared water resources, and the international agreements and institutions established for this basin must be equipped to recognize and respond to such changes. A review of international agreements and in-depth interviews with water managers throughout the Orange-Senqu basin, reveal a variety of flexibility mechanisms embedded within the existing treaties. Key to the process of adaptation are the broad institutional mandates that enable existing Commissions to recognize the need for change over time and advise the parties to adapt accordingly. While the existing institutions in the Orange-Senqu basin are young and have not been fully tested, the treaties do not restrict the adaptive capacity of the parties to manage water resources.

Water and Security in Sub-Saharan Africa: Emerging Concepts and their Implications for Effective Water Resource Management in the Southern African Region

Africa has 63 river basins that cross the international political borders demarcating the 48 countries making up the African continent (Pakenham 1991: 15). Each of these river basins is shared by between two and ten states and this feature poses several strategic implications for the future economic development aspirations of the countries concerned. Significantly, large areas of Africa are arid or water scarce, where the spatial and temporal distribution of surface water is tightly controlled by the interplay between sparse and erratic rainfall and high evaporation rates. In these areas, the availability of surface water seldom matches the water needs of the respective countries and greater reliance is placed on water drawn from underground aquifers for domestic, agricultural, and industrial use (UNESCO-ISARM 2004: 4). In the extremely dry areas of North Africa, every country re-lies heavily on water drawn from the large shared aquifer systems that characterize this region. Here, the “Great Man-Made River Project” in Libya provides a classical example of this dependence, where the large volumes of water drawn from the Nubian Sandstone Aquifer (shared by Chad, Egypt, Libya, and Sudan) contribute over 90 % of Libya’s national water budget (Kuwairi 2004: 8). The dilemma posed by the erratic availability of water in many African countries has prompted re-searchers to pose two interrelated questions. First, will governments go to war over scarce water re-sources as the finite limits of available supplies are approached? Or will they choose instead to cooperate in the development of joint water management schemes in order to optimize benefits to all? In the context of post Cold War Sub-Saharan Africa, more and more countries are engaging with their neighbours to share their common water resources (Turton 2003a: 32). Increasingly, this process is taking place though sets of negotiated water-sharing regimes that are most easily understood within the frame-work of a Hydropolitical Complex. The best example of this in sub-Saharan Africa is the Southern African Hydropolitical Complex, where water-sharing agreements between states are now a prominent feature of the international relations of the Southern African Development Community (SADC) region. Indeed, such is the importance of these agreements that water resource management is now widely considered as a driver of regional cooperation in its own right (Heyns 2002: 158, 176; Ramoeli 2002: 107; Turton 2003b: 281). In this chapter, we argue that the answer to the dilemma posed above requires an understanding of two critical elements relating to the strategic access to water in the context of water and security in subSaharan Africa. The first element concerns security of supply (of water), with the hydraulic mission of the state being aimed at achieving this fundamental development objective as a foundation for economic growth, social wellbeing and political stability. The second element relates to the need for each state to choose an appropriate strategy or mix of strategies that will achieve and sustain a high level of security of supply. In our analysis, we explore the relevance of the Southern African Hydropolitical Complex, both as an analytical concept and as a possible mechanism for building and sustaining inter-state cooperation, and thereby avoiding possible conflicts over water.

Basin Closure and Issues of Scale: The Southern African Hydropolitical Complex

Southern African countries face serious regional water scarcity constraints to economic growth and development. The water resources in the four most economically diverse countries—South Africa, Botswana, Namibia and Zimbabwe—are approaching closure at the national level. Investigations using the concept of a Hydropolitical Complex, rather than the river basin alone, as the unit of analysis have produced a more subtle understanding of how hydrologically-constrained states are dealing with the problem. The Southern African Hydropolitical Complex (SAHPC) case suggests that where states have water constraints to future economic development options, then the incentives to seek consensual management options are high.

Mercury emissions from point sources in South Africa

As a first step towards assessing Hg levels in a systematic approach in South Africa, representatives from the South African government, academia, research councils and key industries recently initiated a South African Mercury Assessment (SAMA) Programme (Leaner et al., 2006). The SAMA Programme has undertaken some limited Hg inventory development and monitoring studies in South Africa. The preliminary results of those studies and that of Hg monitoring undertaken at Cape Points Global Atmospheric Watch Station (Baker et al., 2002), are discussed in this paper.

Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae

Studies were conducted to determine the effects of a panel of seven nanomaterials (NMs), namely: α-alumina, γ-alumina, precipitated silica; silica fume, calcined silica fume, colloidal antimony pentoxide (Sb(2)O(5)), and superfine amorphous ferric oxide (Fe(2)O(3)), on sediment dwelling invertebrates Chironomus tentans under controlled laboratory conditions. Percentage survival, enzyme activities, growth development, and DNA fragmentation parameters were studied as acute, biochemical, and physiological toxicities of NMs, respectively. Quantitation of catalase and peroxidase enzyme activity demonstrated that toxicant stress of the NMs increased enzyme activity in a concentration dependent fashion across all treatments. The percentage growth length of the test specimens exposed to different NMs was significantly reduced compared to the negative control while only five concentrations were not in the toxic range, namely; Fe(2)O(3) (5 μg/kg); silica fume (5 μg/kg, 50 μg/kg); Sb(2)O(5) (5 μg/kg) and calcined silica fume (5 μg/kg). Genotoxic stress assessed by use of DNA laddering showed complementary findings to the other ecotoxicological endpoints tested in this study--the percentage survival and growth length inhibition.

Unconventional Water Supply Options in South Africa: A Review of Possible Solutions

Abstract South Africa faces escalating freshwater problems and will experience prolonged water deficits within the next 25 to30 years if current patterns of water use continue unchanged. The level of conventional water resources utilization in the country is very high and new approaches are necessary to stretch the limited water supplies available to meet projected demands for water. Significant research into new technologies and sources of supply has been carried out in South Africa and abroad during the past few decades. This has resulted in the development and evaluation of a number of innovative concepts and methodologies, as well as novel adaptations to existing approaches. These concepts and methodologies include: integration of surface water transfers into a national water grid, transfers of untapped surface water resources from countries located to the north of South Africa, exploitation of deep groundwater and the use of aquifers for storage of surplus water, atmospheric water (fog and cloud) harvesting, iceberg water utilization, desalination and direct use of sea water. Some of these options are still theoretical and unproven, while others have reached different stages of practical testing and implementation. Information on these alternatives for water supply is widely scattered over many different sources. This paper reviews the available information and examines some of these unconventional sources and options for future water supply in terms of their technical aspects, potential applications, likely impacts, approximate costs, and regional relevance in terms of alleviating predicted water shortages.

The Orange-Vaal River system

The Khoi (Hottentots) knew the Orange River as the “Gariep”, or Great River. In 1779 it was named Orange River by Colonel Robert J. Gordon, in honour of the Dutch Prince of Orange. It rises at 3200 m AMSL in the Drakensberg Mountains and high plateau of Lesotho, where it is called the Senqu, and flows W with an average gradient of 1.4 m km−1 for c. 2300 km to the Atlantic Ocean at Alexander Bay (Figs 1 & 2). Taking the Vaal as the mainstream, the river is 2500 km in longitudinal profile (Werger 1980). The system is the only one in southern Africa to rise on the edge of the African Plateau and flow W (Wellington 1955). In doing so, it passes from cool-temperate and moist alpine regions (Plate lb) to progressively more arid terrain of the W Atlantic coast. The Orange is the largest river system in Africa south of the Zambezi, with a catchment of 650 000 km2 and two major tributaries: the Caledon, forming the western border of Lesotho, and the Vaal (Fig. 1). The Vaal, as the third largest river in South Africa, drains most of the Orange Free State and the southern Transvaal (Fig. 1).