The importance of water quality to the food industry in South Africa

Understanding the Food Energy Water Nexus

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AUTHORSPaul J Oberholster and Anna-Maria Botha

ABOUT THIS STUDY Food, water and energy security form the basis of a self-sufficient economy, but as a water-scarce country with little arable land and a dependence on oil imports, South Africa’s economy is testing the limits of its resource constraints. WWF believes that a possible crisis in any of the three systems will directly affect the other two and that such a crisis may be imminent as the era of inexpensive food draws to a close.

WWF received funding from the British High Commission to establish a research programme exploring the complex relationship between food, water and energy systems from the perspective of a sustainable and secure future for the country. This paper is one of nine papers in Understanding the Food Energy Water Nexus Study.

PAPERS IN THIS STUDY1. Climate change, the Food Energy Water Nexus and food security in South Africa : Suzanne Carter and Manisha Gulati2. Developing an understanding of the energy implications of wasted food and waste disposal: Philippa Notten,

Tjasa Bole-Rentel and Natasha Rambaran3. Energy as an input in the food value chain: Kyle Mason-Jones, Philippa Notten and Natasha Rambaran4. Foodinflationandfinancialflows: David Hampton and Kate Weinberg5. The importance of water quality to the food industry in South Africa: Paul Oberholster and Anna-Maria Botha 6. The agricultural sector as a biofuels producer in South Africa: Alan Brent7. Virtual water: James Dabrowski8. Water as an input into the food value chain: Hannah Baleta and Guy Pegram9. Water, energy and food: A Review of integrated planning in South Africa: Sumayya Goga and Guy Pegram

ABOUT WWFThe World Wide Fund for Nature is one of the World’s largest and most respected independent conservation organisations, with almost five million supporters and a global network active in over 100 countries. WWF’s mission is to stop the degradation of the Earth’s natural environment and to build a future in which humans live in harmony with nature, by conserving the world’s biological diversity, ensuring that the use of renewable natural resources is sustainable, and promoting the reduction of pollution and wasteful consumption.

DISCLAIMERThe views expressed in this paper do not necessarily reflect those of WWF. You are welcome to quote the information in this paper provided that you acknowledge WWF, the authors and the source. If you would like to share copies of this paper, please do so in this printed or PDF format.

In conducting the analysis in this paper, the authors have endeavoured to use the best information available at the time of publication. The authors accept no responsibility for any loss occasioned by any person acting or refraining from acting as a result of reliance on this paper.

CITATIONShould you wish to reference this paper, please do so as follows:Oberholster, P.J. and Botha, A-M. 2014. Importance of water quality to the food industry in South Africa. Understanding the Food Energy Water Nexus. WWF-SA, South Africa.

For further information please contact:

Manisha Gulati at mgulati@wwf.org.za orTatjana von Bormann at tvbormann@wwf.org.za

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ABSTRACTSouth Africa’s water, energy and food sustainability are tightly linked. Water is required to extract energy and generate power, while energy is needed to treat and transport water. Both energy and water are prerequisites for food sustainability. It is thus evident that one area can impact on one or both of the other areas. However, the most important challenge facing the South African Food Energy Water Nexus is water quality. Water quality in the food sector is influenced by numerous anthropogenic sources, of which coal mining is one of the major drivers. However, there is an interdependency in that energy in the form of coal-generated electricity is required for the production and delivery of food, the pumping of irrigation water and the transport, distribution and storage of food.

KEY WORDSAnthropogenic pollution, coal mining, waste-water treatment plants, processing industry, water management

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CONTENTS

ABSTRACT

1. Introduction 5

2. Sources of water contamination from a food sector perspective 5

3. The role of energy extraction and production activities, and waste disposal from energy production, 6

in water contamination

3.1 Coal mining as key for power production 6

3.2 The role of coal-fired power stations and industries 7

4. Potential points of food contamination linked to water quality 8

5. The risks associated with the use of poor quality water for the food sector and human health 8

5.1 Adverse effects of high metal concentration on crops and human health 8

5.2 Endocrine disruptors or endocrine-disrupting chemicals (EDCs) from industrial effluent 9

5.3 Risk of microbial contamination 10

6. The impact of poor water quality on food export, with emphasis on access to market 11

Case study: Berg River, Western Cape 11

7. Prevention of food contamination and different management options 11

7.1 Management of metal contamination in the food industry 11

7.2 Management of EDC contamination in the food industry 12

7.3 Management of microbial contamination in the food industry 12

7.4 The protection of ecological structures to improve water quality 12

8. Conclusion 12

REFERENCES 13

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1. INTRODUCTION Although energy, water and food sustainability are often perceived as separate challenges in South Africa, these are in fact highly interdependent problems. The quest to secure energy, water and food sustainability is complicated by the reality of the links between these systems. Water, for example, is needed to process coal and generate thermoelectric power, and energy is required for the production of food and the treatment of waste water. Although water is the central element in the Food Energy Water Nexus, the awakened concern about water-quality issues and their possible adverse effects on the food industry in South Africa have only been realised over the last two decades.

In 2003 the agricultural sector contributed 3.8% to the gross domestic product (GDP) (i.e. USD 159.9 billion) (OECD FAO 2005). In Africa, South Africa is the leading exporter of fresh fruit and vegetables with exports to the USA totalling 73% in accordance with the African Growth and Opportunity Act (AGOA) (Ndiame & Jaffee 2005). South Africa is also the largest third-world exporter of fruit and vegetables to the European Union (EU) and is ranked the second-largest southern hemisphere exporter of deciduous and stone fruit. Apart from the export market, 20% of the fresh fruit is consumed locally, while 20% is processed into fruit juices (WESGRO 2006).

2. SOURCES OF WATER CONTAMINATION FROM A FOOD SECTOR PERSPECTIVEWater quality in the food sector of South Africa is influenced by numerous anthropogenic sources, which include the following:

(a) Mining and smelting operations, which are important causes of heavy-metal contamination in the environment due to activities such as mineral excavation, smelting and refining, and the disposal of tailings and waste water around mines. Mining activities are a significant contributor to waste products that negatively impact on the water quality, acting mainly as a point source pollutant through acid mine drainage (AMD). AMD is characterised by low pH, elevated heavy metals, sulphates and total dissolved solids (TDS).

(b) Effluent of untreated and partly treated sewage from several point sources, e.g. failing sewage systems and poor sanitation in informal settlements. These sewage outflows can contain high levels of Escherichia coli (E. coli), which is an indicator of faecal contamination.

(c) Coal-fired power plants and industrial activities, which ultimately contribute to acid rain and pollution through high deposition levels of oxides of sulphur and nitrogen, which can change the chemical structure of agriculture soils.

(d) Industrial effluence containing pharmaceutical endocrine-disrupting chemicals (EDCs) from manufacturing factories, e.g. products like shampoo, pesticides, dyes and plastics.

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3. THE ROLE OF ENERGY EXTRACTION AND PRODUCTION ACTIVITIES, AND WASTE DISPOSAL FROM ENERGY PRODUCTION, IN WATER CONTAMINATION3.1. COAL MINING AS KEY FOR POWER PRODUCTIONSouth Africa contributes 5% of the global recoverable coal reserves and is the world’s sixth largest coal producer (220 Mt/yr) (DME 2004). The Witbank coalfields represent the largest conterminous area of active coal mining in South Africa, with a permitted discharge of about 50 Ml/d of acidic and partly saline mine water into the Olifants River catchment (Maree et al. 2004). Of South Africa’s electricity, 56% is produced in this catchment through the use of coal-fired power stations. Electricity generated from these power stations is used in the agricultural sector for irrigation and in the food industry for food processing. However, the AMD legacy of coal mining forms part of this power generation process and poses a danger to ecosystem services. The impact of AMD can last for long periods and is multifaceted (Figure 1).

Overall, AMD weakens the ecological stability by reducing the biodiversity, disrupting the food web and polluting surface and groundwater on which human lives are so dependent (Oberholster et al. 2013c). AMD results from thedecanting of water from abandoned mines, where the exposed sulfide minerals (mostly pyrite Fe2S) make contact with the water and oxygen.

This contact initiates the oxidation of sulfide minerals, producing sulfuric acid (Van Rensburg 2003). The rate of acid generation is determined by factors like the surface area of exposed metal sulfide, oxygen content, pH and the bacterial activity of Acidothiobacillus ferroxidans, Thiobacillus ferroxidans and Leprosprillum ferroxidans that directly and indirectly catalyse the reaction involved (Schrenk et al. 1998; Edwards et al. 2000; Akcil & Koldas 2006). The highly acidic water (pH 2 to 4) then drains into the natural water system. It alters the physico-chemical properties of the water and consequently the biological and ecological structure of the aquatic system (Gray 1998). For example, under acidic conditions (< pH 4), the carbonate and bicarbonate are converted to carbonic acid, which dissociates into carbon dioxide and water.

This conversion has two effects:• it reduces the buffering capacity of the aquatic system, and• it reduces photosynthesis of flora as this activity uses bicarbonate as the inorganic carbon source in

photosynthetic organisms (Ashton et al. 2001).

Water with low pH facilitates the dissolution and mobilisation of metals from various sources like the exposed minerals in the mines, rocks and soil. This greatly elevates the level of metals within a water system and may exceed the standard and tolerable limits as their bioavailability to the food web increases. However, the bioavailability is metal-specific when considering interaction with other factors involved such as pH, temperature, dissolved organic carbon (DOC), interaction with other metals and Ca2+ levels (Wren & Stephenson 1991; Schubauer-Berigan et al. 1993; Playle 1998).

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Figure 1: AMD effluence from the Klip River into the Olifants River, Mpumalanga

Photo: Jackie Dabrowski

3.2 THE ROLE OF COAL-FIRED POWER STATIONS AND INDUSTRIESEmissions from coal-fired power stations and industries can contain sulphur dioxide (SO2), which forms a strong mineral acid when dissolved in water–this is commonly known as acid rain (Figure 2). Acid rain leaches calcium, magnesium and metals from the soil, transporting them through surface run-off into streams and rivers, negatively affecting water quality for aquatic life. Usually, rain dilutes contaminants within the river system. However, when air pollutants occur in high concentrations they can dissolve in atmospheric moisture, thereby adding to the water-pollution problem in a system. Any wet atmospheric deposition that has a pH below 5.6 is classified as acid rain(Wang 2008). Oberholster et al. (2010a) measured a < pH 5 average for rainwater in the Upper Olifants River catchment, possibly caused by coal-fired power station and industry emissions.

Figure 2: Emissions from coal-fired power stations and industries

Photo: Jackie Dabrowski

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Rainwater is naturally acidic since atmospheric carbon dioxide dissolves in moisture to form carbonic acid (H2CO3)–this gives rainwater a pH of 5.6 (Wang 2008). During rain run-off, this weak carbonic acid dissolves minerals from the geologic substrates it interacts with, thereby liberating minerals for plant uptake (Wang 2008). Although small amounts of nitrous oxides (NO3) can be attributed to lightning storms, large amounts of contaminants like sulphur dioxide (SO2) and nitrous oxides are released during fossil-fuel combustion (Wang 2008). When these substances come into contact with moisture, two strong acids are produced: sulphuric acid and nitric acid. Not only can these acids cause severe damage to infrastructure but they can also release toxic metals that are only soluble at lower pH levels. This leads to increased metal toxicity within the water system and agriculture soils. Furthermore, mercury can be found in coal, mostly combined with sulphur, and can be released into the atmosphere upon combustion by coal-fired power stations. Mercury is a persistent and toxic substance that can be accumulated in the food chain.

4. POTENTIAL POINTS OF FOOD CONTAMINATION LINKED TO WATER QUALITYThe food-processing industry involves the total environment from farm to customer, presenting numerous pathways for the potential contamination of food. According to Gelting et al. (2011) irrigation water has been found to be a major source of faecal contamination with many outbreaks of related diseases linked to contaminated irrigation water. In South Africa the annual water usage for irrigation purposes is 59% of the total water requirement (Backeberg 2005) with river and dam water as the main irrigation source (Oberholster et al. 2009; 2010a; 2013b). Certain rivers in South Africa, however, have been reported to contain high levels of microbial pollutants (especially E. coli) which can act as a vehicle for food contamination (Genthe et al. 2013).

In this chain, the main pre-harvest sources of contamination include: (a) irrigation water, (b) manure, (c) soil and (d) inadequate sanitation, while post-harvesting pathways of contamination are from food handling.

The following contamination routes of food are particularly relevant to consumers: (a) while it is in its raw or unprocessed state, (b) during processing, (c) during packaging, (d) during transportation and (e) during delivery and display. Although most of these can be managed with relative ease, exposure pathways of crops to toxic metals through contaminated soil and water are more difficult to manage. In a recent study, accumulation of toxic metals in fresh produce and grain crops was reported (Botha et al. 2013).

5. THE RISKS ASSOCIATED WITH USE OF POOR QUALITY WATER FOR THE FOOD SECTOR AND HUMAN HEALTH5.1. ADVERSE EFFECTS OF HIGH METAL CONCENTRATIONS ON CROPS AND HUMAN HEALTHHeavy metal pollutants can cause severe problems for crops; under high concentrations in soil they are toxic to the plants themselves and to natural microbial soil populations. These abiotic heavy metals can negatively affect biomass production and yields in almost all major crops (Athar & Ahmad 2002 and references within) and seem to lower soil pH levels (Chunilall et al. 2005). Athar and Ahmad (2002) reported that heavy-metal pollution can not only result in lower plant growth rates (ranging from 13% to 70%), but also in a decrease in the yield of wheat (40% to 83%). Studies reported that Al3+ dominating low pH water retards germination rates and root development, which thereby reduces the crop yields (Delhaize & Ryan 1995; Botha et al. 2013). The protein content of the exposed plants was also shown to decrease by between 19% and 71% under different metal-pollution levels. Alarmingly, heavy metals can be taken up in relation to the amount applied (Chunilall et al. 2005) (though less when metals were added in combination) and stored in grains, for example (Athar & Ahmad 2002).

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Gorbunov and co-workers (2003) showed in their study that a variety of toxic and heavy metals (Cr, Fe, Ni, Cu, Zn, As, Cd, Sb, Hg, Pb) in food and agricultural products (meat, eggs, bread, etc.) were dependent not only on the concentration in the soil, but also upon the quality of the irrigation water, processing and growing practices. The levels of these metals in food were also dependent on their mobility, i.e. their chemical form, and the ease with which they could be absorbed by the plants. These researchers concluded that if agricultural lands were watered with contaminated “sewage” water, an increase in the concentration of metals could be observed in the end product if the water had contained heavy metals. Chunilall et al. (2004) showed that metals like Pb, Hg, Cd and Ni were easily absorbed by spinach leaves when irrigated with water containing higher than usual levels of heavy metals. The intake of excessive heavy metals could be a potential health hazard to humans and may lead to poisoning, such as microelementosis (Gorbunov et al. 2003). The risk of certain diseases such as chronic toxicity and organ malfunction is thought to be greater with increased consumption of heavy metals by humans (Chunilall et al. 2004). Livestock fed on feed containing heavy metals accumulate these metals in their meat, for example, thereby not only moving heavy metals along the food chain, but also accumulating it along the way (Gorbunov et al. 2003; Liu 2003; Oberholster 2012). The metal load present in decanting AMD poses a potential health risk to humans via direct and indirect ingestion (drinking water and food intake respectively) and is a primary concern (Pruvot et al. 2006).

It has been shown that the trace metal, aluminium (Al), has adverse effects on root growth and development, even at low concentrations (Delhaize & Ryan 1995). Solubilisation of aluminium is enhanced under lower pH conditions and thus toxic to plants (Ryan & Kochian 1993; Mossor-Pietraszewska 2001). Exposure of plants to high levels of Al can lead to Al toxicity, of which the most prominent symptom is the inhibition of root growth (Ryan & Kochian 1993; Delhaize & Ryan 1995; Mossor-Pietraszewska 2001; Botha et al. 2013). Al is mainly taken up through the root apex (Mossor-Pietraszewska 2001), which is also the major site of Al toxicity (Ryan & Kochian 1993; Delhaize & Ryan 1995; Mossor-Pietraszewska 2001). In the soil, Al is present in various compounds/states, only some of which are toxic to the plant (Mossor-Pietraszewska 2001). The symptoms of Al are brought about by the biochemical effects of the toxicity, i.e. the inhibition of cell division, cell extension and transport (Mossor-Pietraszewska 2001). As a result of Al toxicity, nutrient and water uptake is inhibited (Ryan & Kochian 1993; Delhaize & Ryan 1995; Mossor-Pietraszewska 2001). Many studies such as Pruvot et al. (2006) and Zhuang et al. (2009) have found that accumulation of trace metals in edible plant parts may pose a risk to human and animal health.

Athar and Ahmad (2002) found in their study that the number of Azotobacter chroococcum, free-living nitrogen fixers, also decreases with increases in metals–up to 84% in the presence of Cadmium (Cd) and 100% when metals were applied in combination. Azotobacter is beneficial to crops in that it secretes antifungal substances, vitamins and growth-promoting substances and helps with phosphate solubilisation.

5.2. ENDOCRINE DISRUPTORS OR ENDOCRINE-DISRUPTING CHEMICALS (EDCS) FROM INDUSTRIAL EFFLUENTIt is a known fact that South Africa has used and abused most chemicals listed by developed and developing countries as endocrine-disrupting chemicals (Burger & Nel 2008). Endocrine disruptors or endocrine disrupting chemicals (EDCs) can be natural or man-made and have the potential to alter the normal functioning of the endocrine system. The endocrine system is responsible for guiding the development, growth, reproduction and behaviour of both humans and animals (IPCS 2002). An understanding of the human bodily functions and the role of the endocrine system is necessary to fully appreciate the effect that EDCs have on a living organism. The endocrine system regulates processes as diverse as blood pressure, smooth muscle contraction, fluid balance and bone metabolism (IPCS 2002). For many of these systems the setup is “programmed” during foetal development. An abnormal environment during this critical stage can therefore result in permanent mis-programming (IPCS 2002).

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To complicate our ability to measure endocrine disrupting effects, these substances are found to have trans-gen-er-ational capabilities (IPCS 2002; American Chemical Society 1998), meaning that not only can these adverse effects result from exposure of either parent prior to conception, but also from exposure of the developing embryo in utero, or the progeny after birth (Daston et al. 2003). In simple terms, this implies that our exposure to these chemicals may only manifest and become apparent in our grandchildren, but could be visible in all three generations. Chemicals suspected of being endocrine disruptors are pharmaceuticals (e.g. birth control), personal care products (e.g. shampoo, lotions, perfumes, cosmetics, sunblock) and industrial substances (e.g. plasticisers, fabric softeners and cooling agents). These chemicals find their way into our environment and we are in contact with them through all the major exposure routes such as the air we breathe, water we ingest, food we consume, and by absorption through our skin. Effects of these substances on animals have been widely published (from subtle changes in physiology and sexual behaviour to permanently altered sexual differentiation of wildlife species; a marked population decline in Baltic seals; eggshell thinning and altered gonadal development in birds of prey) (IPCS 2002).

5.3. RISK OF MICROBIAL CONTAMINATIONFood and water can serve as vehicles that transmit microbial contamination (Figure 3). Microbial pollutants of water resources pose a serious health risk to humans and animals; these include Escherichia coli, Shigella spp., Salmonella spp. and protozoan parasites such as Cryptosporidium hominis and Giardia lamblia species. The latter are regarded as important pathogens since they can cause diarrhoea in humans and animals, which may result in the death of immunocompromised individuals, children with malnutrition, transplant recipients, patients receiving chemotherapy for cancer and patients with immunosuppressive infectious diseases (Fayer et al. 2000). South Africa regularly experiences outbreaks of diarrhoea, which may be associated with the use of contaminated water. In 2005, for example, in the town of Delmas situated in the upper Olifants River catchment, an outbreak resulted in 528 reported cases with four deaths and 69 people hospitalised. The outbreak is thought to have been attributed to microbial contamination of water resources (SANDMC 2009), although subsequent studies in this area could not identify the causative agent. Waterborne diarrhoeal outbreaks where no aetiological agent is detected may be attributed to Cryptosporidium spp. and Giardia spp.

Figure 3: Discharge of untreated sewage containing high levels of microbials in the Upper Olifants River catchment

Photo: Oberholster et al., 2013a and b

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6. THE IMPACT OF POOR WATER QUALITY ON FOOD EXPORT, WITH EMPHASIS ON ACCESS TO MARKET

CASE STUDY: BERG RIVER, WESTERN CAPE The Western Cape has the highest rate of growth and development in agriculture in South Africa - the fruit and vegetable sector in particular–and generates about 25% of the agricultural sector’s total gross income, as well as 50% of produce exported from South Africa (WESGRO 2006). The Berg River in the Western Cape serves as one of the most important water supply services in the region with a total irrigation area of about 23 000 ha, and production from irrigation contributing a gross farm-gate value of about R1.3 billion. According to the Western Cape Integrated Water Resource Management (IWRM) Action Plan, however, three major water-quality issues are of concern in the Berg River, namely (a) salinity, (b) nutrient enrichment and (c) microbial pollution. The pollution of Berg River irrigation water especially (microbial pollution from E. coli), is of great concern.

In a recent report by Britz et al. (2007) it was stated that the water of the Berg River, which, as discussed, plays a major role in the Western Cape’s agricultural sector, doesn’t fall within the European Union’s (EU) allowable microbial standards for food production. The main source of pollution is from the informal settlements close to the river as well as raw and untreated sewage that ends up in the Berg River from waste-water treatment plants in the Paarl and Wellington areas. During the 2004–2005 season, export markets were in danger when rumours surfaced about the microbial pollution, and retailers threatened to cancel fruit imports from the region. Since 75% of the export crop from this region is destined for the UK and European markets, which are very sensitive to water-quality issues and use GlobalGap standards to audit fresh produce, this income stream was in danger. The estimated loss to the export market in this region could be anything from R190 to R570 million depending on the percentage loss in market access (Louw 2010). Added to the potential direct loss of income are multiplier impacts on the provincial, and possibly national, economy, since the direct farm employment (excluding packing and the rest of the supply chain) is approximately 14 291 permanent labourers and 16 680 seasonal (permanent equivalent) labourers (Louw 2010).

7. PREVENTION OF FOOD CONTAMINATION AND DIFFERENT MANAGEMENT OPTIONS7.1 MANAGEMENT OF METAL CONTAMINATION IN THE FOOD INDUSTRYThere is an increasing concern about the hazards of toxic metals in the food chain. In many countries legislative and administrative measures have been put in place to prevent adverse effects on consumers by exposure to toxic metals in food. However, in South Africa guidelines of this nature and relevant to the human food chain are not in place with regard to the production of different crop species on contaminated agricultural soils. In the Netherlands, a soil protection policy has been developed with associated soil-quality standards known as ‘ABC’ values (McGrath et al. 1994). The action value, or ‘C’, indicates concentrations above which there is a danger that the functional properties of soils for animal and plant production will have been reduced. Other guidelines that have also been used are those of the United States Environmental Protection Agency (US EPA), with metal limits indicating the level which is considered to pose no significant threat to public health (US EPA 1993). In South Africa, data must still be gathered to construct comprehensive dose–effect curves for different crop species in relation to toxic metals and contaminated soils, to formulate guidelines that can be used by the various food industries.

The Bottom Line: Any food crops grown with contaminated water will inevitably have to be tested and monitored to verify the presence of dangerous contaminants.

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7.2 MANAGEMENT OF EDC CONTAMINATION IN THE FOOD INDUSTRYEven though there has been an increasing concern over the last two decades about the likely impact of exposure in the environment to chemical compounds with endocrine-disrupting activity, South Africa still faces challenges in the area of proper waste disposal from numerous industries and the agricultural sector. Olujimi et al. (2010) highlighted treated waste water from municipal treatment plants and landfill sites as areas of importance that have been neglected in the monitoring of EDCs in the South African environment.

7.3 MANAGEMENT OF MICROBIAL CONTAMINATION IN THE FOOD INDUSTRYEffective and preventive measures are important to avoid the contamination of fresh produce by good personal hygiene and safe food-handling practices. These safety initiatives must also include avoiding the use of contaminated manure; providing proper sanitary systems and hand-washing facilities for food handlers; the use of clean equipment and transportation vehicles, and good hygiene in processing facilities. Other measures that can be put in place are the implementation of Good Manufacturing Practice (GMP) programmes in the produce industry (Bihn & Gravani 2006) as well as Good Agriculture Practices (GAPs) for irrigation water.

Restoring and upgrading sewerage systems and improving poor sanitation in informal settlements are prerequisites for reducing contamination to protect the food industry. These issues, a result of poor service delivery and the financial constraints hampering many local government departments, are possibly some of the most important challenges in South Africa today.

7.4 THE PROTECTION OF ECOLOGICAL STRUCTURES TO IMPROVE WATER QUALITYVegetated buffer strips are suggested to be one of the most effective ways of mitigating the non-point source microbial, phosphorus and metal pollution of water resources. Meals (2001) suggested that a combination of vegetated buffer strips and riparian zones shows a significant decline in microbial counts. Riparian zones are naturally occurring within the flood area of rivers or streams and need to be protected to improve downstream ecosystem services. Another management option that can be employed by the agricultural and mining sector as a mitigation tool against contamination of the receiving streams is the protection of natural wetlands. It is widely accepted that natural wetlands can play a major role in water purification of non-point source pollution such as microbially contaminated manure used in the agricultural sector.

8. CONCLUSIONIt can be concluded that the quality of South Africa’s freshwater resources is fundamentally important to ensure food security. Freshwater, being a limited resource, needs to be managed carefully. The problems discussed in this paper emphasise the continuous and urgent need for sound water management with respect to both abundance and quality within the Food Energy Water Nexus.

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