In view of the key water challenges, which were identified in the Business Case for the Limpopo Catchment Management Area, namely:
- "Water resources nearly fully developed with all available water being highly utilised
- Limited options for further resource development exists - attributable to the arid climate, unfavourable topography, sandy rivers as well as important conservation areas
- Resources and requirements approximately in balance at present
- Implementation of the Reserve is expected to result in serious deficits in some of the main river catchments
- Planning has been made for large new mining developments in the Mokapane-Mogoto area for which additional water will be required
- Urban and industrial growth will mainly be concentrated in the Johannesburg, Tswane and Polokwane areas, where local water resources already are in short supply and need to be augmented by transfers from other WMAs.
- There are severe eutrophication problems at dams in the WMA.
- Possibility for new power stations and/or petrochemical industries to be developed around the coalfields in the Lephalale area
- Water pollution owing to large quantities of effluent discharged into the rivers in urban and industrial areas in the WMA
We are of the considered opinion that it would be of vital importance to, prior to the issuing of the proposed classes under section 13(4) of the National Water Act (NWA), that the Resource Quality Objectives for the Catchment be determined.
It is our understanding that the Resource Water Quality Objectives (RWQOs) provide a mechanism through which the balance between sustainable and optimal water use and protection of the water resource can be achieved and to establish clear goals relating to the quality of the relevant water resources. The RWQOs will provide the basis for determining the allocable water quality and the water quality stress and are based on the designated users of the water resources. The classification of proposed classes of water resources should be aligned with the RWQOs.
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Comments and Request for Information Pertaining to the Determination of Resource Quality Objectives in the Upper Vaal Water Management Area Draft Resource Quality Objectives Report (Draft 2) Resource Quality Objectives And Numerical Limits Report
REPORT NO: RDM/WMA08/00/CON/RQO/0613
....civil society is fully competent to fully conceive the risks of:
- sulphate, chloride, metal and TENORM contamination of soils and sediments, surface water bodies, ground water,
- the contamination of crop soils irrigated with contaminated surface water or contaminated groundwater,
- the concomitant loss of genetic/biodiversity and potentially ecosystem goods and services on disturbed, fragmented or polluted properties
- bioaccumulation of some metals and TENORM by flora and fauna
- the exposure of fauna and humans to bioaccumulated pollutants
- acute and latent toxicity impacts of bioaccumulated pollutants on humans and the potential for radioactivity impacts from TENORMs on humans
as a result of gold mining. The gold deposits on the Witwatersrand Basin naturally co-occur with uranium, other NORMs and metals such as Mg, Cu, Zn, Mn, As, Ni, Cr, Co and Pb. In addition, long-lived cyanide-metal complexes persist in tailing storage facilities. The latent impacts on biota, including humans, of bioaccumulation and exposure to elevated levels of metals and TENORMS are well established in the international scientific literature.
In view of the above-mentioned we strongly recommend that a precautionary or risk averse approach be adopted in the determination of RQOs for the Upper Vaal.
We have a perplexing difficulty which we are trying to solve. Such is the difficulty: Why were the values for sulphate and U not determined in the RQOs for this IUA? And, what is the numerical value of sulphate within a D category – 200mg/l, 500mg/l or more? Will the sulphate levels within a D category render the water fit for use for its users? We respectfully request you to please assist us in this regard.
The short- and medium term treatment of AMD is currently releasing approximately 40ML/d highly saline water into the Elsburgspruit which flows into the Natalspruit and eventually into the Klip River. Sulphate concentrations will therefore increase dramatically as a result of the discharge of neutralised AMD but also as a result of the added mine drainage seepages from surface mine residue deposits.
Partially treated mine water was discharged into the Blesbokspruit system and indirectly into the Rietspruit thus polluting the water in this river system and changing its ecology.
With the flooding of the Grootvlei Mine, the pumping stopped and pre-mining flow patterns and volumes were restored. The short and medium term treatment of AMD within the Eastern and Central Basins involves pumping and the discharge of approximately 60 – 80 ML/d and approximately 40ML/d of highly saline water into the Blesbokspruit and the Klipriver.
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Chris Dickens of the Institute of Natural Resources NPC responded:
The Klip River (Gauteng) (UJ), the Mooi River (UL), Blesbokspruit River, the Boskop Dam, Donaldson Dam, and the Gerhard Minnebron (considered as a wetland in the study) have indeed all been prioritised/have RU’s. Erroneously we did not link the name of some of these rivers to the prioritised RU correctly in some versions of the report (Suikerbosrand, Blesbokspruit and Klip River) for which many of the salt and toxicant RQOs were already determined. This has now been corrected in the report.
Where recommendations were made (and justified with literature) we have added appropriate RQOs to address your comments for all of these ecosystems. Some of the variables that may pose a threat of toxicity to human health through direct contact and consumption of fish (excluding consumption of water) have not been included in prioritised RUs as very little information is available to propose a numerical limit for these toxicants. However the following regional requirement for the IUA has been included that should cater for this concern: “The consumption of fish harvested from rivers in the IUA must not pose a threat to human health. The water quality in the rivers of the IUA must not pose a threat to human health through direct contact (excludes consumption of water)”.
In consideration of the dam RQOs we have added Uranium as a toxicant where applicable and the narrative that: “There is potential of toxicity of heavy metals associated with AMD and radioactive nucleotides. The water quality in the rivers/dams of the IUA must not pose a threat to human health through direct contact (excludes consumption of water)”. This addresses the requirement for toxicity consideration for the dams. This includes the wetland ecosystem “Gerhard Minnebron”. Finally although we acknowledge that sediment plays an important role in the storage of toxicants we have only considered the threat of toxicity in water which is more in contact with the ecosystem and people. Monitoring of sediments is a possibility but has not been included for practical reasons.
The advantage of making use of a “D EcoStatus” category is that this refers to the minimum allowable integrity state of an ecosystem which is still in a sustainable state. What this means in terms of WQ concentrations, is that no matter how good or bad the science is, it still needs to be demonstrated that the ecosystem is in a sustainable state. Thus this protects us against bad science. Having said that, this EcoStatus of a D does not determine acceptability for human use, however it is the general situation that the two are aligned. Things like radioactivity are in fact more easily tested against the ecosystem as the biota are exposed 24 hours per day, and if they do not show excessive negative impacts, then it could be concluded that the water is safe for humans.