Wonderfonteinspruit Catchment Area

Areas of Concern

Martin van Veelen

June 2008

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Contents

• Introduction• Objective• Approach• Methodology• Results

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Acknowledgement

• The information presented here was derived from work done by Professor Frank Winde, School of Environmental Sciences and Development, North West University

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Introduction

• A Specialist Task Team has been appointed by the DWAF and the NNR to formulate a plan of action for the remediation of radioactive contamination in the Wonderfonteinspruit Catchment Area

• The STT consists of local and international specialists

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STT Composition

• Mr Marius Keet :DWAF :Proj Man• Dr Martin van Veelen :Team Leader• Ms Kavita Pema :Admin• Mr Mogwera Khoathane• Ms Gugu Mlangeni• Prof Frank Winde• Prof Gerrit Basson• Mr Ronald Cohen• Dr Gert de Beer• Dr Don Lush

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Objective

• The objective is to identify, categorize and prioritise areas where radioactivity as a result of mining activities poses a health risk to the community, with the view of developing a plan of action to reduce the risk to acceptable levels

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Approach

• Use information from existing studies– IWQS (1999)– WRC 1214 (2004)– BSA (2007) (‘Brenck Report’)

• Define what constitutes risk– Level of contamination– Accessibility

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Methodology

• Create a base map– River system– Mining activities– Human activities– Geology– Areas identified by previous studies

• Assess risk• Categorise and rank

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Base Maps

• IWQS (1999) focussed on uranium in water

• Council for Geoscience (2004) focussed on sediment

• BSA (2007) considered pathways

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IWQS (1999)

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Council For Geoscience (2004)

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BSA(2007)

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Risk (1)

Risk Factors• Level of contamination (40%)

– Level of radioactive contamination• Predominantly U238• Exceptional cases Ra226

• Exposure (60%)– Accessibility (20%)– Probability of access (20%)– Probability of usage (20%)

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Risk (2)

• In order to categorize risk, each risk factor is weighted according to predetermined criteria:– Low : 1– Medium : 2 – High : 4

• HR =0,4CL+0,2A+0,2AP+0,2UP (HR: 1…4 )

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Outcome Categories

• low risk: 1 to <2: requires further studies before establishing possible need for interventions

• medium risk: 2 to 3: requires further studies, may necessitate medium-term intervention

• high risk: >3 to 4: requires immediate intervention

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Contamination

Class Natural Legislativebackground limit

• low < 10x <1x• medium 10x to 100x 1x to 2x• high >100x >2x

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Accessibility

• low (1x):areas in large wetlands, remote fenced farms, other access-controlled private properties etc.

• medium (2x): public areas, river banks, wetlands, stream channels, canals, dams etc. accessed by nearby roads, informal paths etc.

• high (4x): areas designated for public use e.g. functioning as established recreational sites (Donaldson Dam, A. Bailey Nature Reserve, etc.)

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Access probability

• low (1x): -remote areas well away from larger settlements (>5km walking distance, >15km driving distance), and no special attraction (such as fishing, swimming etc.), and no of local residents <10

• medium (2x): -areas in the vicinity of larger settlements (2-5km walking distance), or some features of special attraction (such as fishing, swimming etc.), or 10-30 local residents

• high (4x):-areas next to larger settlements (<2km walking distance), or site has special attraction (such as fishing, swimming etc.), or >30 local residents

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Usage probability

• low (1x): -remote groundwater boreholes not used for domestic or agricultural purpose, -sediments in inaccessible areas such as large wetland with dense vegetation -sediments in sufficiently deep dams where no remobilisation occurs through normal activities (swimming, fishing….)

• medium (2x): -boreholes used for domestic/ agric. purpose,-surface water (streams, dams, mine canals)-water used for fishing, swimming-sediments in shallow dams, floodplain soil at commercial farms, no nearby informal settlements

• high (4x):-surface water in streams, dams, mine canals or -sediments in shallow dams, wetlands, floodplain soil in vicinity to townships/ informal settlements-areas with salt crusts-communal gardens in floodplain farming on contaminated site

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Conclusion

• The map is a work in process and not meant to be conclusive

• The areas of concern are categorised and do not represent a quantification

• It identifies priority areas for urgent action

• All contamination will have to addressed in due course