FIRST ORDER ASSESSMENT OF THE QUANTITY AND QUALITY OF NON-POINT SOURCES OF POLLUTION ASSOCIATED WITH INDUSTRIAL, MINING AND POWER GENERATION Report to the Water Research Commission by RG Heath*, HD van Zyl**, CF Schutte***, JJ Schoeman*** * Golder Associates Africa (Pty) Ltd ** Tshwane University of Technology *** University of Pretoria WRC Report No. 1627/1/09 ISBN 978-1-77005-819-4 NOVEMBER 2009 Non- Point Source Pollution Assessment DISCLAIMER This report has been reviewed by the Water Research Commission (WRC) and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the WRC, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. ii Non- Point Source Pollution Assessment EXECUTIVE SUMMARY Internationally it has become recognised that Non-Point Sources of pollution (also known as diffuse source of pollution) plays a major role in the degradation of water quality, specifically with respect to salinity, eutrophication (nutrient enrichment), sediments, pathogens, pesticides (including persistent organic pollutants – POPs) and some heavy metals. It is now accepted that it is not feasible to properly manage water quality without addressing the contribution from non point sources. Consequently, attention is increasingly being devoted to the quantification of non point water source pollution and to identify means to control it cost-effectively at source. In order to provide strategic direction to research initiatives and to ensure that all important potential Non- Point pollution sectors of the economy are receiving the required attention, the Water Research Commission initiated this study “To compile a first order inventory of the quantity and quality of water produced as non-point sources by the South African industrial, mining and power generation sectors, and assess the impact these have on the quality of the water resources”. In-depth literature reviews on the mining industry, the industrial and power generation sectors were undertaken in an attempt to assist with the first order assessment of non point sources of pollution from these sectors in South Africa. The limited available information on non point pollution has been compiled into a consolidated overview that presents the current status of literature and available data for the industrial, mining and power generation sectors. Much of the information is available in reports and documents that have been prepared for different purposes. Although much is already known internationally about non-point pollution there is a dearth of available published, information in South Africa. The majority of the available information is only available in reports that have not been published or in a form that needs manipulation before relevant information can be derived. In order to collect first order data for those sectors and sub-sectors for which insufficient data are available the following methods of data collection were used to gain information: Presentations to Water Industry of Southern Africa (WISA) biannual conference and the International Water Association (IWA) annual conference Survey questionnaire to the WISA Industrial Water Division Presentations to selected industries, ESKOM and Chamber of Mines Meetings with specific mining houses, ESKOM and industries Meetings with the regulators Department of Water Affairs and Forestry (DWAF) and Department of Minerals and Energy Water quality data downloaded from DWAF’s databases In depth assessment of available data in reports These meetings did not bring anything new to the table except that non-point pollution is recognised as a contributor to both surface and groundwater pollution. In order to attempt to categorise the water qualities and quantities impacts associated with non-point sources data was synthesise to obtain an estimate of the threat that different mining, industrial and power sectors pose on the water resources. iii Non- Point Source Pollution Assessment Some of the problems that limit the use of the available information and would necessitate further processing to normalise the data, derive from the fact that the investigations producing the information were done at different times to different levels of detail and using different approaches. A further complicating factor is that data for some sectors may not be available and may necessitate further investigation. It must be pointed out that although there is a large amount of information available in the form of reports on special investigations conducted for individual industries, this data is not readily available because industries in general feel uncertain about how this type of information could affect their situation with regard to future applications for water use or wastewater discharge. The overview of water use and waste production by different sectors needs to be interpreted for the effect sectors can be expected to have on receiving water quality. The mining industry is, for example, reportedly responsible for about 80% of the waste production (salts) and is furthermore, the source of acid mine drainage that is threatening the water quality of several important catchments in the country. However, other industries that produce much smaller quantities of waste may actually present an equal or even more serious threat to water quality in the catchments where they operate, especially if they have waste discard facilities that can be sources of non-point pollution after rain or wind events. It would thus be necessary to categorise waste types according to their effect on water quality and synthesise the data to obtain an estimate of the threat that different sectors and sub-sectors pose to receiving water quality. Mining South Africa is globally recognised as being a leading supplier of a variety of minerals and mineral products. Typical pollutants from the mines include sulphates, acidity, salinity and metals (including aluminium, iron and manganese) and may contribute to the three types of non point pollution caused by mining, i.e. surface water, groundwater and atmospheric pollution. Typical contaminants were identified which could potentially have an impact on non-point source pollution, e.g. metal concentration and a risk factor given to each. Typical sources of pollution were then identified, e.g. waste rock dumps, slimes dams, etc. A risk factor was given to each source type of pollution. The risks relate to the potential of the contaminant that originates from a specific source to pollute the surface, atmosphere or groundwater. Gold and coal mining were identified as the mining commodities having the highest potential to contribute to non-point source pollution. This could mainly be attributed to the magnitude at which gold and coal are currently and was historically mined. Although the base metals have a wider range with regards to the type of contaminants produced, the scale of production lowers the risk of contributing to non-point source pollution. Coal and gold mines, especially closed and abandoned mining operations, appear to be the most significant threats in terms of potential groundwater contamination from the mining sector in South Africa. Acid generation and decreasing groundwater pH has been noted in some gold and coal mining areas in South Africa, but in many cases, Acid Mine Drainage is neutralised by reaction with the country rock to produce saline drainage instead. Unfortunately, due to the lack of detailed information, the following factors could not be incorporated into this risk assessment: The differentiation between the impact of the different receptors (e.g. waste rock dumps) and between the different mining commodities. The potential impacts of age of the receptors. iv Non- Point Source Pollution Assessment The role of gas emissions from the different mining commodities. The range (13 to 51%) of potential Non-Point source pollution contributions to salts balances at a catchment scale varied considerably from study to study, commodity mined and season. Despite the uncertainties in the accuracy of these studies the overall contribution of non point source pollution originating from the mining industry in South Africa is significant Industries The industry representatives were hesitant to give permission for the information to be presented in a WRC report. The reasons for this are obvious and understandable since the information is of such a nature that it could reflect negatively on the industries if it is used in a malevolent manner. The collection of non point pollution data from industry has been difficult even though very good cooperation was given by most industry representatives. The overall impression is that the majority of larger industries are well aware of the potential problems associated with non point pollution and that in most cases measures have already been implemented or are being developed to combat this problem. The main ‘hot spots’ in terms of non point sources are the ‘historical’ sites where wastes had been disposed off over long periods of time into inadequately designed facilities and where adequate control was not exercised. These sites are very difficult and extremely costly to rehabilitate and the pollution effects have spread over large areas with contamination of groundwater the most serious problem. The extent of the pollution could not be quantified but from available information the pollution in some historic areas appears to be extensive. The end result of all these