Submissions by Mr. Mike Muller, Director General, DWAF.

7 October, 2004.

Findings of the Water Research Commission (WRC) Report No 1214/1/06 “An assessment of sources, pathways, mechanisms and risks of current and potential future pollution of water and sediments in gold-mining areas of the Wonderfonteinspruit catchment”. 2004.

1.Findings of the National Nuclear Regulator’s (NNR) Report No TR-RRD-07-0006 entitled “Radiological Impacts of the Mining Activities to the Public within the Wonderfonteinspruit Catchment Area”. July 2007.

2. The National Nuclear Regulator’s (NNR) “Status Report on the Actions Arising from the Study of Radiological Contamination of the Wonderfonteinspruit Catchment Area (WCA)”. 29 October 2007.

1.“Threats and opportunities for post-closure development

in dolomitic gold-mining areas of the West Rand and

Far West Rand (South Africa) – a hydraulic view.” 2010.

2.“Uranium Pollution of Water resources in Mined-Out and Active Goldfields of South Africa – A Case Study in the Wonderfonteinspruit Catchment on Extent and Sources of U- Contamination and Associated Health Risks.” 2009. 

Prof. Dr. Frank Winde, North West University. 

Findings of the Department of Mineral Resources’ “Draft Regional Mine Closure Strategy for the Far West Rand Gold Fields”. 2009.

“The finding of the Mooi River (Wonderfonteinspruit) Study of this Department was that Potchefstroom is NOT at risk and that the radioactivity level complied with the most stringent criteria for low radioactivity levels.”

“Studies by the Department of Water Affairs and Forestry have indicated elevated levels of

radioactivity in rivers draining the gold-mining areas of the Witwatersrand. A detailed study

of the Mooi River system (including the Wonderfonteinspruit) showed radioactivity levels in this system to be elevated, although doses to the public from formal drinking water sources were found to be within acceptable limits at most sites.

Following this study, Wade et al. (2002) showed that the river sediments act as a sink, holding

radionuclides, often at concentrations considerably higher than those found in the sources

(gold/uranium ores and mine tailings). Wade has further demonstrated that the uranium in

these sediments may be obilized by changes in water chemistry.” (Emphasis added.)

“The mean values for the Wonderfonteinspruit samples were found to significantly exceed not only natural background concentrations*, but also levels of regulatory concern for cobalt, zinc, arsenic, cadmium and uranium, with uranium and cadmium exhibiting the highest risk coefficients”.

*(The analytical results were compared with a compilation of regulatory limits, exclusion limits and guidelines for contaminant levels in sediments, as well as the global mean values for similar sediments in the geological record.)

“The contaminants of greatest concern are therefore uranium, cadmium, zinc and cobalt, with the median value for uranium concentrations measured in this sampling phase 720 times the local background and for cadmium, 700 times the local background”.

“What about the end users? Direct analyses and long-term integration methods indicate

possible pollution of downstream water resources”

“Potchefstroom is located downstream of the Wonderfonteinspruit, from which more than 400 000

people derive their drinking water via the Boskop Dam.”

“The results of this study indicate that uranium poses a hazard to water users in the

catchment because of its chemical toxicity. A full radiological risk assessment, looking at

both dissolved radionuclides in water and radionuclides bound to sediment, is required to

determine current and future risks due to radioactivity.”

“The measured uranium content of many of the fluvial sediments in the

Wonderfonteinspruit, including those off mine properties and therefore outside the

boundaries of licensed sites, exceeds the exclusion limit for regulation by the National

Nuclear Regulator. A decision is therefore necessary by the NNR, regarding a

regulatory response to this problem.”

“This study showed that past

and present discharges of radionuclides into the Wonderfontein Spruit catchment as a

consequence of mining activities can lead to considerable radiological impacts to the public via

various exposure pathways, exceeding significantly the natural level and also the dose limit for the

public of 1 mSv per annum, at numerous sites.”  (Regional Mine Closure Strategy for the Far West Rand Gold Field. Department of Mineral Resources.)

“For approximately 50% of the 47 sampling sites, the calculated incremental doses of the respective critical group are above 1 mSv per annum up to 100 mSv pa…”  

“The radioactive contamination of surface water bodies in the Wonderfonteinspruit catchment area caused by the long-lasting mine water discharges and diffuse emissions of seepage and runoff from slimes dams poses radiological risks to the public resulting from the usage of polluted environmental media.” 

“The pathway sediment→SPM →cattle→milk/meat→person (“SeCa”) can cause radioactive contamination of livestock products (milk, meat) resulting in effective doses of the public in some orders of magnitude above those resulting via the pathway “WaCa.”  

“It was found that

at 6 of the 10 investigated sites the U-238 activity concentration exceeded 0.2 Bq/g, with the

highest values measured in sediments from the Tudor Dam and Coetzee Dam, and that uranium

might be remobilized from the sediments by changes of pH, redox potential or TDS in the water

column.” (DMR’s Regional Mine Closure Strategies for the Far West Rand. 2009.) 

“Preliminary results of analyses conducted on produce grown in the area have indicated that the dose levels are of radiological concern to the regulator.” (NNR’s Status Report. 2007.) 

“Potential threats associated with uncontrolled

flooding of the mine voids include an initial, severe water

shortage in the WFS lasting between 15 and 60 years, during

which almost no water would be available for maintaining

aquatic ecosystems, farming activities, diluting

municipal wastewaters and, last but not least, recharging

the Boskop-Turffontein Compartment as sole supply of

drinking water to approximately 300 000 inhabitants of the

Potchefstroom municipal area. In a worst-case scenario this

period of filling the mine void and the de-watered dolomitic

compartments could be followed by highly polluted,

radioactive mine-water decanting, via a number of yet

unknown points including existing springs that currently

supply potable water to the Mooi River system, accompanied

by large-scale reactivation of sinkholes in densely populated

areas. It is argued that such a scenario must be

avoided through a combination of building up adequate

rehabilitation funds by the mining industry, governmental

control and improved scientific understanding.” (Emphasis added.)

“Results indicate that U-levels in water resources of the whole catchment increased markedly since 1997 even though U-loads emitted by some large gold mines in the Far West Rand were reduced.  This apparent contradiction is explained by the contribution of highly polluted water decanting from the flooded mine void in the West Rand.

“…800kg of U per year flowing into Boskop Dam as Potchefstroom’s main water reservoir…”

“Of particular concern is the fact that U-levels in the WFS are comparable to those detected in the Northern Cape which had been geostatistically linked to abonormal haematological values related to increased incidences of leukaemia observed in residents of the area”.

(Emphasis added.)

“Status of radioactivity in the Far West Rand (FWR)

“The ores of the Witwatersrand contain appreciable concentrations of uranium, …

“In addition to the uranium, its radioactive

daughter nuclides are likely to be present, and pose a risk to downstream water users, to people

directly exposed to radioactive materials, to windblown radioactive dust and radon gas.

“An airborne radiometric survey of the FWR was done for DWAF (CGS) ). Interpretation of

the data show many of the residential areas (Carletonville, Westonarea, Khutsong) fall within areas

of high risk of radioactivity contamination. Furthermore contamination around surface

discard facilities shows a distinct plume towards surface streams.

“The most important considerations relating to the concerns about water contamination in post

mining times are the fact that the surface water entering the FWR is already contaminated before

entering the area. Water polluted by leachate from mine dumps (AMD) shows characteristically

high sulphate concentration. This will form the greatest threat to groundwater quality after closure.

Surface and groundwater interactions suggest that poor quality surface waters are impacting on

the dolomitic aquifer. The receiving environment of contaminated water from the FWR is the

Boskop Dam, and downstream users in the Mooi River including Potchefstroom. Conditions exist for

uranium to be transported in solution in these waters. It is possible that radiogenic material may

migrate, dissolved in groundwater, to be consumed at some other point where radioactive

contamination may not be expected.”  (Emphasis added.)

“There are a number of boreholes (roughly 200) in the entire West Rand dolomitic compartments,

where water level measurements are taken at regular intervals by the Potchefstroom DWAF

Hydrology office. .. The Department undertakes no

groundwater quality monitoring at this stage”.