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

[摘要] English: South Africa has only recently realized that organic groundwater contamination occurs in this country andthat 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 NAPLin specific. The understanding of NAPL pollution problems, is however, still very limited. Hencegroundwater practitioners confronted with NAPL pollution problems have burning questions regardingamongst others the characterization of the pollution, which is much more sophisticated than in the case ofinorganic pollution. While in this phase, groundwater practitioners can not even begin to considerremedial efforts for contaminated sites, which continue to pollute the groundwater. It is therefore ofparamount importance to get up to speed with technologies and practices accepted worldwide forcharacterization. Much improvement is still needed on these characterization methods, but South Africacan 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 thenature of the problem, which is why Chapter 2 describes the current situation of organic groundwaterpollution and the associated vulnerability of aquifers in South Africa. The general understanding ofgroundwater pollution by NAPL is distorted, not only in the eyes of the public, but also in the eyes ofexperts in the groundwater field. A general misconception is that NAPL pollution only occurs at heavyindustries such as ISCOR and SASOL, but Chapter 2 clearly shows that organic pollution is much morewidespread and sinister in nature than would have been thought before. Smaller urban activities and smallindustries have been identified to be just as large a contributor towards organic pollution as the heavyindustries. Shortcomings in the current understanding of NAPL pollution have been highlighted inChapter 2 and further studies can be focused on determining the current impact of various industries ongroundwater in South Africa, as well as delineating towns in which leaking underground storage tanksmay 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. Theseconcerns need to be addressed by making the applicable policies and regulations, and implementing theseregulations. In order to shed light on how site assessment and characterization can be performed in SouthAfrica, Chapters 4, 5, 6 and 7 address issues associated with site assessment and characterization. Riskassessment has also been addressed (Chapter 8) and several shortcomings, to be addressed bytoxicologists and groundwater practitioners, have been highlighted.It was clear from the investigations performed throughout this thesis, that several shortcomings exist inassociation with site assessment, site characterization and risk assessment, which will need to beaddressed in the near future.

[发布机构] University of the Free State