Design of a National Radioactivity Monitoring Programme (NRMP) to monitor surface water resources in South Africa

The Department of Water Affairs and Forestry (DWAF) has carried out a number of case studies on the radiological quality for the water resources near gold mining activities in South Africa. Elevated levels of radioactivity were found in some areas. It thus became important to establish a national monitoring programme that will report on the radiological quality of South Africa's water resources in order to comply with the water resource quality monitoring requirements of the National Water Act (Act 36 of 1998). The purpose of the National Radioactivity Monitoring Programme (NRMP) is to establish the status of, and trends in, radioactivity levels in South African water resources and to report on their radiological quality on a regular basis. This paper discusses issues and decisions taken with regard to the design of the NRMP. A screening method, using alpha/beta activity is proposed to estimate total radioactivity in surface water resources. Where elevated levels of radioactivity have been identified, an element specific analysis will follow. A biweekly sampling frequency has been recommended. Sampling site selection is catchment based and includes sites in high-risk areas. Where possible, use will be made of existing water quality and flow monitoring sites.