LIST OF TABLES
3.4 DISCUSSION AND CONCLUSION
44 | N o r t h W e s t U n i v e r s i t y had stigmasterol, a plant sterol found in plant fats and oils (Baxter et al., 1999). Large amounts of β-sitosterol were found among horse and sheep profiles, but less in cattle faeces.
This is contradictory since they are all herbivores. All the herbivore species showed large amounts of stigmastanol and stigmasterol compared to the other species. This is because of their diet, as stigmasterol and stigmastanol are both terrestrial sterol biomarkers (Leeming, 2006).
45 | N o r t h W e s t U n i v e r s i t y (14.297 ppm). Coprostanol and cholesterol concentrations were, however, far above that of dehydrocholesterol (DCHL), stigmasterol (SROL), stigmastanol (SNOL) and β-sitosterol (β- SITO), which also eluted in human sterol profile. The high abundance of cholesterol may be because a raw sewage sample was taken to be analysed. This sample may contain other organic matter (eg. plant rests), which could possibly have contributed to the amount of cholesterol in the sample. Leeming et al., (1996), also determined that the main faecal biomarker for herbivores was 24-ethylcoprostanol. Although 24-ethylcoprostanol was not used as a target sterol in this method (Szűcs et al., 2006), it did elute in the sterol profiles of herbivores as determined by Leeming et al., (1996), and was thus shown on the chromatograms of the sterols (Figure 12 a-c). The concentration could however, not be determined as no standard was acquired for 24-ethylcoprostanol. Herbivore sterol profiles all had traces of terrestrial sterol biomarkers, because of the animals’ diet. In the sterol profile of bird faeces, both 5β and 5 stanols were low compared to β-sitosterol. Birds possess an inability (due to the lack of specific bifidobacteria) to convert cholesterol to 5β-stanols (Leeming et al., 1996), which explains why the cholesterol concentration was higher than all other sterol concentrations. Pigs and sheep were found to have sterol profiles similar to that of humans, although the concentrations of sterols found varied immensely (Table 2).
The main conclusion from this part of the study is that faecal sterol biomarkers have unique source specificity dependent on a combination of sterol intake and the metabolic production of sterols produced by microbial biota in the digestive tracts of various animal species. It can therefore be concluded that the ‘sterol fingerprints’ of human and animals are sufficiently distinctive to be of value in determining the quality of environmental water and the origin of faecal pollution in water samples.
46 | N o r t h W e s t U n i v e r s i t y
4
Applications in using sterol analysis in the
determination of groundwater and surface water quality
Groundwater resources occur in openings in the rock material in the subsurface (DWAF, 2004a). These openings are fracture zones in hard rocks and dissolved fissures in dolomites (in the North West Province) (Colvin, 2007), these specific openings are mostly recharged by rainfall and stream infiltration (DWAF, 2004a). Groundwater resources act as reservoirs and slowly release water back to rivers and wetlands. Ecosystems connected to these groundwater replenishment zones are dependent on the water they provide all year round (Colvin, 2007).
Pollution of groundwater in the North West and Northern Cape Provinces are a main challenge as rural communities depend almost exclusively on these water resources for drinking purposes (Kalule-Sabiti and Heath, 2008; Woodford et al., 2009). These communities obtain their drinking water directly from uncovered or covered boreholes and wells (Kalule-Sabiti and Heath, 2008). There are four main routes by which groundwater can be contaminated, 1.) infiltration; 2.) direct migration; 3.) inter-aquifer exchange; and, 4.) recharge from surface water (Barcelona et al., 1988). Thus, microbiological pollution of groundwater is most probably caused by human and animal activities, which include on-site sanitation, cemeteries, waste disposal, feedlots and un-sewered settlements (Engelbrecht and Tredoux, 2000). In certain areas, the groundwater does not comply with the DWAF and SANS 241 limits set for physico-chemical properties, microbial indicators or trace elements (Engelbrecht and Tredoux, 2000). Recently, Mpenyana-Monyatsi and Momba, (2012),
47 | N o r t h W e s t U n i v e r s i t y conducted a study of groundwater in rural areas of the NWP and concluded that 86% of the boreholes tested did not comply with the limits set by the national guidelines (SANS 241 and DWAF) in terms of faecal (FC) (0 cfu/100 ml) and total coliforms (TC) (0 to 5 cfu/100 ml).
In most urban areas in South Africa, surface water are utilized more readily that groundwater.
Surface water systems in the NWP consist of dams, rivers, wetlands, and pans (NWDACE- SoER, 2008). A large portion of available surface water in the North West and Northern Cape Provinces contributes to the mining, agricultural and industrial sectors (Kalule-sabiti and Heath, 2008). Surface water quality in the North West and Northern Cape Provinces are impacted by a number of point and non-point source factors; these include, acid mine drainage, domestic and industrial sewage effluents, and agricultural and storm run-off (NWDACE-SoER, 2008). Additionally, raw municipal waste water is sometimes discharged into the rivers and dams in these Provinces, introducing a wide range of potentially infectious agents into the rivers (Awofolu et al., 2007). Surface water in the NWP is critical for socio- economic growth and poverty reduction, and plays a central role in providing water recreational, cultural and religious beliefs of the people in communities (Molale, 2012).
Groundwater in this study was collected from boreholes and water storage tanks in townships across the North West and Northern Cape Provinces, South Africa. These groundwater samples were of significant bad quality (Results, 4.3A). As previously mentioned, groundwater is of vital importance in the North-West and Northern Cape Provinces as it is in many instances the only source of water for many rural people (Mpenyana-Monyatsi and Momba, 2012). We know from previous studies done on boreholes in the NWP that a large number of groundwater sources in the Province are contaminated (Momba et al., 2006;
Mpenyana-Monyatsi and Momba, 2012).
48 | N o r t h W e s t U n i v e r s i t y Surface water collected and analysed in this study was gathered from the Harts River and Baberspan Nature reserve situated between Delareyville and Sannieshof in the NWP, South Africa. The Harts River falls under the Lower Vaal WMA (Water Management Area) and is regulated by the Taung and Spitskop dams and the Little Harts River and the Great Hearts River (DWAF, 2009c). The Lower Vaal WMA is located on the north-western region of South Africa, and borders Botswana in the North (DWAF, 2009). Intensive irrigation practices happen in this area and they include the planting and harvesting of maize, wheat and cotton (Ferreira, 2008), as well as extensive livestock farming of beef, dairy, goats and sheep (DWAF, 2004a). According to Ellington (2003) the water quality of the Harts River can be impacted by irrigation return flows and the Vaal Harts irrigation scheme, which contributes fertilizer and salts to the Harts River from the Upper and Middel Vaal. The Harts River is connected with an off channel-pan, Baberspan, by a channel (DWAF, 2004a). The Baberspan bird sanctuary is one of the largest waterfowl sanctuaries in South Africa (Anon6, 1997;
NWP-SoeR, 2002). It consists of 2000 ha body of water, which is of international importance for migratory birds (Anon6, 1997; DWAF, 2002). It lies between Sannieshof and Delareyville in the NWP of South Africa (DWAF, 2004a). Baberspan is the largest of a series of pans that lie in the fossil bed of the Harts River. More than 12 000 birds and over 365 bird species have been recorded here (Swart and Cowan, 1994; Anon6, 1997). The pan is state controlled and is used for angling and bird watching, while land use surrounding the pan include cattle and maize farming (Swart and Cowan, 1994).
49 | N o r t h W e s t U n i v e r s i t y