Although naturally occurring in groundwater, nitrate presence is generally attributed and
regarded as a contaminant. Elevated nitrate levels pose a threat once converted to nitrite,
causing methaemoglobinaemia. This investigation serves to establish the origin, quantify
the extent, distribution, and elucidate possible amelioration methods of nitrate in ground and
surface waters of a chrome mine in Kroondal, South Africa. Already existing surface water
and borehole (groundwater) points were sampled and monitored from 2011 to 2012. An
independant sample collection was conducted twice during the year of 2012. ICP and
isotope (hydrogen, oxygen and nitrogen) analysis were employed to see nitrate level
behaviour. In 2011 and 2012, nitrate level elevations varied from acceptable to
unacceptable, with maximums of up to 81.51 mg/l in both ground and surface waters (well
above the Department of Water Affairs and Forestry domestic requirements of 10 mg/l).
Hydrofacies plots attribute water chemistry to: calcium/magnesium bicarbonate, opencast
mine, low sodium high salt and unpolluted waters. Domination in Mg cations occurs as
would be expected within Bushveld Igneous Complex aquifers. This is a result of the
abundance within mafic and ultramafic igneous rocks. Increased Nitrate concentrations in
surface waters are suspected to be primarily a result of runoff from waste rock dumps, high
in nitrate explosive residues. In groundwater, increased concentrations are suspected to be
primarily a result of high nitrate concentrations in explosive residues from underground
blasting, highly mobilised once in contact with water. A secondary cause is seepage from
the tailings dam, waste rock, as well as from surface water, high in nitrate concentrations.
Possible remediation strategies identified include Reverse Osmosis, Eco-Dosing and
Biological De-Nitrification.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-07182013-105630 |
| Date | 18 July 2013 |
| Creators | Milanzi, Kenneth Sayed Remofiloe |
| Contributors | Prof M Tredoux, Dr PD Vermeulen |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-07182013-105630/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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