Site characterization and risk assessment of organic groundwater contaminants in South Africa

English: South Africa has only recently realized that organic groundwater contamination occurs in this country and that it can have a serious effect on the groundwater quality. The Water Research Commission (WRC) recently launched studies to investigate Non Aqueous Phase Liquid (NAPL) pollution, and Dense NAPL in specific. The understanding of NAPL pollution problems, is however, still very limited. Hence groundwater practitioners confronted with NAPL pollution problems have burning questions regarding amongst others the characterization of the pollution, which is much more sophisticated than in the case of inorganic pollution. While in this phase, groundwater practitioners can not even begin to consider remedial efforts for contaminated sites, which continue to pollute the groundwater. It is therefore of paramount importance to get up to speed with technologies and practices accepted worldwide for characterization. Much improvement is still needed on these characterization methods, but South Africa can learn from past mistakes made by other countries in addressing NAPL pollution. In order to begin contemplating addressing NAPL characterization, it is important to understand the nature of the problem, which is why Chapter 2 describes the current situation of organic groundwater pollution and the associated vulnerability of aquifers in South Africa. The general understanding of groundwater pollution by NAPL is distorted, not only in the eyes of the public, but also in the eyes of experts in the groundwater field. A general misconception is that NAPL pollution only occurs at heavy industries such as ISCOR and SASOL, but Chapter 2 clearly shows that organic pollution is much more widespread and sinister in nature than would have been thought before. Smaller urban activities and small industries have been identified to be just as large a contributor towards organic pollution as the heavy industries. Shortcomings in the current understanding of NAPL pollution have been highlighted in Chapter 2 and further studies can be focused on determining the current impact of various industries on groundwater in South Africa, as well as delineating towns in which leaking underground storage tanks may be a problem. In order to address the NAPL pollution problem, legislative tools have to be in place. Gaps in legislation have therefore also been highlighted, of which several are listed in Chapter 3. These concerns need to be addressed by making the applicable policies and regulations, and implementing these regulations. In order to shed light on how site assessment and characterization can be performed in South Africa, Chapters 4, 5, 6 and 7 address issues associated with site assessment and characterization. Risk assessment has also been addressed (Chapter 8) and several shortcomings, to be addressed by toxicologists and groundwater practitioners, have been highlighted. It was clear from the investigations performed throughout this thesis, that several shortcomings exist in association with site assessment, site characterization and risk assessment, which will need to be addressed in the near future.