E N T E R . 2000. A pit-stop semi-nested PCR assay for the detection of toxigenic Vibrio cholerae in environmental water samples was developed and its performance evaluated. The PCR technique ampli®es sequences within the cholera toxin operon speci®c for toxigenic V. cholerae. The PCR procedure coupled with an enrichment culture detected as few as four V. cholerae organisms in pure culture. Treated sewage, surface, ground and drinking water samples were seeded with V. cholerae and following enrichment, a detection limit of as few as 1 V. cholerae cfu ml À1 was obtained with ampli®cation reactions from crude bacterial lysates. The proposed method, which includes a combination of enrichment, rapid sample preparation and a pit-stop semi-nested PCR, could be applicable in the rapid detection of toxigenic V. cholerae in environmental water samples.

No abstract

Environmental Affairs, Edna Molewa, was succinct in her summary: 'The situation currently in South Africa is that we have 98% of the water in the country being considered "fully allocated". This means that my child and your child that is being born tomorrow has 2% of water for use going into the future.' AFRICAN FUTURES PAPER 11 | SEPTEMBER 2014 Parched prospectsThe emerging water crisis in South AfricaSteve Hedden and Jakkie Cilliers Other demand forecasts Modelling water supply and demandTo forecast South Africa's water sector, Future water supply in South AfricaThis section reviews water supply from surface water, groundwater, water reuse and desalination (see Figure 4). Forecasting the demandsupply gapTo model the NWRS2's ability to close the gap between demand and supply, the authors built a supply forecast that simulates the NWRS2 plans to increase supply utilising the IFs model. Water is therefore a significant constraint on South Africa's development potential and the next section looks at how this gap can be closed. South Africa is rapidly approaching this limit and, in the case of the Orange River, has already passed the limit. Closing the gap UncertaintiesThe demand-supply forecast presented in this paper is not the only possible water-demand scenario for South Africa.There are many uncertainties that will affect both the supply and demand of water resources. In the base case scenario, it is assumed that the levels of exploitable surface and groundwater In line with some of the key messages from the reconciliation strategies laid out in the NWRS2, it is evident that 'South Africa cannot afford to waste any water, anywhere, any more'. 82 More specifically:• Groundwater is important, and currently undervalued and under-used, especially in small-scale rural farming.It may emerge as the most important way in which any expansion in the agricultural sector is possible. The reality is that reallocating some water from irrigation to other use may have to be considered in certain areas.• There is huge potential to increase the reuse of municipal and industrial water at the coast and in inland systems.In addition, wastewater needs to be treated in all water-use sectors, especially in highly contaminating industrial sectors, such as mining.• There is limited opportunity for more dams or transfer schemes, but they are inevitable in certain areas. This option is very expensive.• Due to the high levels of evaporation and transpiration loss in South Africa, the storage of water in aquifers has to be considered as part of future policy or alternative ways need to be found to reduce evaporation.• Expensive desalination projects would have to be considered as an option to increase supply of water, especially in coastal areas with limited alternative sources of supply.• The necessary incentives should be put in place for the transition to a recycling economy, in which water of different quality and price is used for different purposes.• Monitoring and evaluation of the water sector is necessary to set and ...

No abstract

No abstract