The six-legged flying squad

How do bugs and insects help forensic entomologists to settle disputes and solve crimes? Martin Villet and Nikite Muller explain

The use of Daphnia spp. and indigenous river invertebrates in whole effluent toxicity testing in the Vaal Catchment.

Freshwater is vital to societal, and environmental, well-being and any changes in the distribution, abundance and quality of water resources and ecosystems are detrimental to this societal and environmental sus-tainability. Increasing socio-economic activities world-wide have been accompanied by increased pollution stress on the aquatic environment. The need for improved efficiency in water quality management is urgent and immediate and it is important that policy to manage freshwater sys-tems is underpinned by sound science. Strategies to manage receiving water quality have been implemented world-wide and include chemical monitoring, biological monitoring and toxicological assessments, all of which are supported by on-going research. Water quality management in South Africa has come a long way since 1919, when it was first promulgated (Union Health Act 36 of 1919; van der Merwe and Grobler, 1990) but only included sewage effluent. Later amendments broadened water quality management to include effluent discharge from industry, mining and storm-water runoff. However, despite these and uniform, and general, effluent standards (UES), as well as DWAFs recognition of the need for integrated water resource management, water quality in the resources continue to deteriorate (DWAF, 1995; Basson etal 1997)

Environmental water quality in water resources management

This book will help anyone working with water resources to make decisions about water quality, specifically environmental aspects of water quality. The book ex-plores the balance between water resource protection and water resource use, with a particular focus on water quality. A balance is necessary because the National Wa-ter Act (NWA) requires that water resources be protected and managed to meet the water quality requirements of ecosystems. At the same time the Act also requires that water be used for social and economic benefit

Use of indigenous riverine invertebrates in applied toxicology and water resource-quality management

The National Water Policy (DWAF, 1997). and the National Water Act (No 36 of 1998)(NWA) provide the legal and management context for the application of results. The law and the policy are founded on the concepts of equity (fairness of access to water and water services) and sustainability (the opportunity to optimally use water resources now and into the future)(NWA, l (l)(xviii)(b)). The concept of sustainability is based on the understanding that on earth water comes packaged in aquatic ecosystems, and that the product, water, is intimately related to and affected by the structure and functioning of these ecosys-tems.(Aquatic ecosystems include rivers, lakes, wetlands, aquifers and estuaries. Impoundments act as artificial lakes connected to river sys-tems.) A key recognition during the development of the policy and the NWA was that" the environment" does not compete with users for re-sources-the environment (in this case aquatic ecosystems) is the re-source. Therefore a key poiicy of DWAF is that vi resource protection in order to achieve sustainable resource use. Resource protection is achieved through the implementation of resource directed measures (RDM) and source directed controls (SDC)

Ecological impacts of small dams on South African rivers Part 1: Drivers of change–water quantity and quality

Impacts of large dams are well-known and quantifiable, while small dams have generally been perceived as benign, both socially and envi-ronmentally. The present study quantifies the cumulative impacts of small dams on the water quality (physico-chemistry and invertebrate biotic indices) and quantity (discharge) of downstream rivers in 2 South African regions. The information from 2 South African national data-bases was used for evaluating the cumulative impacts on water quality and quantity. Physico-chemistry and biological data were obtained from the River Health Programme, and discharge data at stream flow gauges was obtained from the Hydrological Information System. Multivariate analyses were conducted to establish broad patterns for cumulative impacts of small dams across the 2 regions–Western Cape (winter rain-fall, temperate, south-western coast) and Mpumalanga (summer rain-fall, tropical, eastern coast). Multivariate analyses found that the chang-es in macroinvertebrate indices and the stream’s physico-chemistry were more strongly correlated with the density of small dams in the catchment (as a measure of cumulative impact potential) relative to the storage capacity of large dams. T-tests on the data, not including sam-ples with upstream large dams, indicated that the high density of small dams significantly reduced low flows and increased certain physico-chemistry variables (particularly total dissolved salts) in both the re-gions, along with associated significant reductions in a macroinverte-brate index (SASS4 average score per taxon). Regional differences were apparent in the results for discharge reductions and the macroin-vertebrate index. The results suggest that the cumulative effect of a high number of small dams is impacting the quality and quantity of wa-ters in South African rivers and that these impacts need to be systemat-ically incorporated into the monitoring protocol of the environmental wa-ter requirements

Evaluating The Potential Contribution Of Episodic Toxicity Data To Environmental Water Quality Management In South Africa

An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to explore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment

Ecological impacts of small dams on South African rivers Part 2: Biotic response–abundance and composition of macroinvertebrate communities

This paper investigates the cumulative impacts of small dams on inver-tebrate communities in 2 regions of South Africa–the Western Cape and Mpumalanga. Previous research found reduced discharge, in-creased total dissolved salts, and a decrease in average score per tax-on (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigat-ed using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catch-ment in foothill-gravel streams (in both Western Cape and Mpuma-langa) and in foothill-cobble streams (in Western Cape only). Opportun-istic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and sea-sons) and detailed (at species level) collection of data to verify the re-sults of cumulative effects of small dams. This can further the devel-opment of a framework for small-dam construction and management that will limit their impact on river catchments

Applied aquatic ecotoxicology sub-lethal methods, whole effluent testing and communication

This report is the most recent in a series of WRC reports on the development of the capacity to undertake ecotoxicological research in South Africa. The development followed the following tines: • Recognition, as a result of the Kruger National Park Rivers Research Programme, that there were virtually no data on the water quality requirements of South African macroin vertebrates. • Development of the capacity to undertake experimental tolerance testing using riverine invertebrates in artificial stream systems. • Investigation of the salt tolerances, and whole effluent toxicity responses, of both standard toxicity test taxa and South African macroinverte-brates. • Development of both lethal and sub-lethal measures. • Application of re-search results to the development of methods for water quality within ecological Reserve determinations, and the implementation of the National Water Act (NWA) (No 36. of 1998) and National Water Resource Strategy (NWRS). The WRC is com-mitted to funding research that underpins the implementation of the NWA and the NWRS. Over the past 12 years it became clear that there would not be a rapid up-take of ecotoxicology research results in South Africa, and that it was important to place ecotoxicology in the wider context of water quality. From this recognition, the concept of Environmental Water Quality evolved

The development of water quality methods within ecological Reserve assessments, and links to environmental flows

In the South African National Water Act (NWA, No 36 of 1998), the eco-logical Reserve is defined as the quality and quantity of water required to ensure appropriate protection of water resources, so as to secure ecologically sustainable development and use. Aquatic ecosystems are recognised as the core location of water resources, and although con-siderable progress has been made in developing methods for quantify-ing environmental flow requirements, this paper describes and discuss-es the first agreed method for quantifying environmental water quality requirements in an ecological Reserve assessment. Integration of flow and water quality is emphasised, and is based on the philosophy that environmental flows should be motivated to provide ecologically im-portant flow-related habitat, or geomorphological function, but should not be motivated to solve water quality problems by dilution. Water qual-ity is multivariate, and not all variables can be considered in an ecologi-cal Reserve assessment, but core water quality variables include: sys-tem variables (salts, dissolved oxygen, turbidity, temperature), nutrients (phosphate, nitrite, nitrate) and toxic substances (those listed in the South African Water Quality Guidelines for Aquatic Ecosystems, includ-ing toxic metal ions, toxic organic substances, and/or substances from a chemical inventory of an effluent or discharge). In addition, biological indicator data (eg SASS data), chlorophyll-a (eg phytoplankton and pe-riphyton data) and toxicity test data may be used. For each variable, a concentration range or response is linked to a class within a water re-source classification system, where classes range from minimally to severely modified

Early development of water quality methods and approaches in ecological Reserve assessments

This project was initiated in 2000 to allow the ecological Reserve team for water quality to undertake additional research while working on eco-logical Reserve determinations funded by the Department of Water Af-fairs and Forestry. The results of this work form the basis of the meth-ods reported in the Water Research Commission report Hughes DA (Ed)(in press)