B Walmsley, SAIEA

UNDP-GEF TDA – findings on water quality� Key known trans-boundary issues:� Eutrophication (esp. in Caledon River)� Microbiological organisms and pathogens (esp. in

Caledon River)� Salinity (Vaal to Lower Orange during floods)

� Possible trans-boundary issues:� Persistent organic pollutants (POPs) (Vaal to Lower

Orange)� Heavy metals (Vaal to Lower Orange)� Radio-nuclides (Vaal to Lower Orange)

Persistent organic pollutants� POPs are organic compounds that resist photolytic,

chemical and biological degradation and also have toxic properties;� They have low water solubility, but are readily soluble

in lipid and can therefore accumulate in fatty tissues;� They have extremely long persistence times;� They can be transported via water, air and biotic

components of the environment far from their original source.

Stockholm Convention� Aim: to eliminate or reduce the production or release

of 12 identified POPs:� Pesticides: aldrin, dieldrin, DDT, endrin, heptachlor,

chlordane, hexachlorobenzene, mirex and toxaphene;� Classes of compounds including: dioxins (PCDD),

dibenzofurans (PCDF) and polychlorinated biphenyls (PCBs);

� SA and Lesotho have signed the Convention;� Namibia and Botswana have acceded to the

Convention.

Sources of POPs� Pesticides (herbicides, insecticides, fungicides etc)

usually applied by spraying to crops;� Aldrin, DDT (except it is still being used to control

Malaria), dieldrin and heptachlor have all been banned in SA;

� PCDD/PCDFs: combustion processes, especially waste burning and waste incinerators where the temperatures are not high enough;� PCBs: were used extensively in electrical transformers

and capacitors, as well as in rubberised paints, glues and plastics before being banned.

http://www.pdfcomplete.com/cms/hppl/tabid/108/Default.aspx?r=q8b3uige22

Status of information on POPs in SA rivers� Heath and Claasen conducted a study in 1999 on

pesticides in SA rivers and found high pesticide loads (including some of the banned substances) in fish tissues. � None of the rivers investigated included any in the Orange-

Senqu basin� Vosloo and Bouwman conducted a study on POPs in river

sediments in 2005, including 6 sampling sites in the basin: Gariep (Orange) River mouth, Douglas Weir, Vaal dam, Rietspruit (vd Bijlpark) x2, Loch Vaal (vd Bijlpark)� Vosloo currently working on new WRC project in basin:� In 2005, sediment samples collected every 50km from mouth

to Vaal confluence, and then along Vaal;� Two samples collected above confluence at Orania and d/s

vdKloof dam;� Replicate samples still in storage.

Vosloo and Bouwman findingsSample site PCB-TEQ

(ng/kg)PCDD/F-TEQ

(ng/kg)Total TEQ

(ng/kg)TEQ

normalised* (ng/kg)

Orange River mouth

0.01 0.22 0.23 370.70

Douglas weir 0.03 0.21 0.24 20.30

Vaal dam 0.01 0.23 0.24 -

Rietspruit 1 0.31 0.84 1.14 62.83

Rietspruit 2 10.01 11.90 21.90 302.54

Loch Vaal 0.65 2.25 2.90 134.11

USA ‘action ‘ level is 50 ng/kg* Normalised for the organic carbon content of the sediment samples

Environmental impacts of POPs� Impaired reproduction and development;� Immuno-suppression;� Cancer;� P-450 enzyme induction and andreno-toxicity;� Endochrine disruption;

Increased burden on the health care systemsGreater susceptibility to diseases

Challenges� Lack of data in Basin states on POPs;� Lack of suitable laboratories to analyse sediment and

tissue samples for POPs – although Vosloo has some equipment for PCDD/F, dl-PCBs and a TCDD-eq;� High cost of analysis overseas;� Lack of effective enforcement;� Lack of a basin-wide, comprehensive monitoring plan

and funding to implement such plan;� High cost to import technology to deal with

problems;� Lack of public awareness.

Heavy metals� Usually include: Fe, Mn, Hg, Pb, Co, Cu, Zn, Cd, Ni, Cr;� Also trace elements e.g. Be, Bi, B, Se etc;� Can be highly toxic, even in trace amounts;� Toxicity depends on the chemical species of the metal, the

presence of other metals and organic compounds, flow rate and volume of water, nature of sediments, water temperature, pH and salinity;� Close correlation between acidity and heavy metal

pollution;� Persist in sediments unless pH drops and they become

soluble.

Sources of heavy metals� Mines e.g.:� Coal mines – low pH, Fe, Mn, Al, B, plus high salt loads� Gold mines – Fe, CN, plus high salt loads� Base metal mines – those in catchment are far from river;

� Industries e.g. steel mills, power stations, metal refineries, pulp and paper plants, petro-chemical plants e.g. Sasol, manufacturing plants, tanneries, textile factories, etc;� Municipal areas e.g. landfill sites, waste water treatment

plants, general storm water runoff from urban areas;� Pesticides, typically Hg, As and Se;� Fertilisers, such as Zn, Cu, B.

� Map of land use

Status of information

Findings� From the work done, it is known that there are high

levels of heavy metal contamination from sources in the Vaal catchment:� Coal mining and power station areas of the Upper Vaal;� Entire Vaal triangle area in the Upper Vaal (including

West and East Rand gold mines);� The Klerksdorp-Orkney gold mining area of the Middle

Vaal;� The Welkom-Virginia area (Free State Gold Mines) in

the Sand-Vet catchment;� Possibly from pesticide use in the Lower Orange.

Environmental impacts� Reduction in biodiversity and spp richness;� Changes in spp composition (loss of less tolerant spp);� Irreversible damage to vertebrates;� Bio-accumulation up the food chain;� Increased cost of potable and industrial water

treatment – leading to higher consumer prices;� Significant health risks to humans from a variety of

sources.

Challenges� Lack of comprehensive monitoring data;� Sample analysis for heavy metals is expensive;� Lack of enforcement and control of polluters;� Lack of prosecution of offenders;� Poor planning e.g. siting of landfills, WWTWs and

sludge farms near rivers or shallow groundwater aquifers.

Radio-nuclides� Uranium is/was recovered as a by-product of the gold

mines, particularly on the East and West Rand and in the Free State Goldfields;� Uranium and its decay products are thus found in

tailings dams, low grade stockpiles, waste rock dumps and in the footprints of old sand dumps;� Main contaminants in water: uranium, radium and

radon (gas).

Status of information� Several DWAF and NNR studies on radio-activity in

the Mooi River (Wonderfonteinspruit catchment) (1999, 2007, 2009?)� DWAF: Report on the Radioactivity Monitoring

Programme in the Klip River Catchment, 2003� DWAF: A Survey on the Radiological and Chemical

Quality of the Water Resources in Selected Sites of the Northern Cape Province, 2005� Studies done by individual consultants, researchers

and the mines over many years.

Findings� Little public information available;� Significant pollution is occurring;� Risk of uptake through several pathways: direct water

consumption; stock watering, irrigation of crops.

Environmental impacts� Exposure to radioactivity can have mutagenic and

carcinogenic effects on all forms of life, either directly or indirectly through the food chain

Challenges� Lack of comprehensive data;� Lack of public disclosure;� Lack of enforcement;� High costs to remediate;� Very complex exercise to calculate individual annual

doses and thus determine risk.

Conclusions� Need a coordinated long-term monitoring

programme to analyse the presence and significance of POPs, heavy metal and radio-nuclide contamination in sediments and fish tissue in the Orange-Senqu River Basin in order to determine the risks of trans-boundary pollution and public exposure.

Recommendations� Phase 1� Use Vosloo’s sediment samples and analyse for selected pesticides

or indicators (?);� Need to ascertain if samples adequately preserved to allow heavy

metal analysis as well;� If yes, analyse selected heavy metals, including uranium;� If not, take samples for analysis of heavy metals at same sites;� Liaise with the NNR and DWA regarding their radionuclide

sampling programmes and try to link;� Use sampling stations already established by Vosloo for aquatic

health monitoring so can link results to WQ;� Take fish tissue samples during the aquatic health monitoring

exercise for analysis of POPs, heavy metals and radionuclides;� Identify main areas of concern for future sampling;� Determine key indicators to use in future sampling in liaison with

Namibian authorities.

Recommendations contd.� Phase 2� Conduct regular monitoring (e.g. quarterly) of

sediment, WQ and fish for key indicators of POPs, heavy metals (and radio-nuclides) at ‘critical’ sites over 2 years;� Continue less frequent monitoring (e.g. annual) of key

indicators at ‘warning’ sites;� Link to water flow data;� Use students to do sampling – link to ongoing research

studies at Potch for example.