Thesis (MSc Food Sc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Fresh produce irrigation water from Western Cape Rivers carries faecal coliforms (FC) (Escherichia coli) at concentrations which often exceed the suggested limit of 1 000 FC per 100 mL and presents a health risk to consumers. On-farm ultraviolet (UV) irradiation presents several advantages for water disinfection but is an uncommon practice in South Africa. The aim of this study was to investigate the use of UV irradiation for river water disinfection prior to irrigation. Escherichia coli (E. coli) strains were exposed to low-pressure (LP) UV (4 mJ.cm-2) and UV/Hydrogen peroxide (H2O2) (4 mJ.cm-2/20 mg.L-1) treatments in Sterile Saline Solution (SSS). Strain variation in reductions was observed and ranged from 1.58 to 3.68 and 1.34 to 3.60 log for the UV and UV/H2O2 treatments, respectively. The UV/H2O2 treatment (4 mJ.cm-2/20 mg.L-1) was more effective, compared to UV singly, against some of the E. coli strains. Selected strains showed increased sensitivity at higher UV doses (8, 10 and 13 mJ.cm-2) and H2O2 concentrations (100 and 200 mg.L-1 with 4 mJ.cm-2) but a 3 log target reduction was not always reached. For all UV and UV/H2O2 treatments maximum resistance was shown by an environmental strain. Reference strains should, therefore, not be used for the optimisation of UV based disinfection parameters. At 10 mJ.cm-2 an American Type Culture Collection (ATCC) reference strain and an environmental strain (ATCC 25922 and F11.2) were both significantly less inactivated in sterilised river water compared to SSS. Enhanced water quality allowed for improved inactivation of the ATCC strain. Also, the efficiency of LP UV (5, 7 and 10 mJ.cm-2) and medium-pressure (MP) UV (13, 17 and 24 mJ.cm-2) radiation was investigated using water from the Plankenburg River. Water was sampled and treated on three respective days (Trials 1 to 3). Physico-chemical and microbiological water quality was always poor. The FC concentration reached a maximum of 6.41 log cfu.100 mL-1 while UV transmission was always below 38%. For LP and MP UV irradiation increased doses resulted in increased disinfection but a 3 log reduction of FC was only attained when MP UV light was used in Trial 1. Disinfection efficiency was dependent on water quality and on the characteristics of the microbial population in the water. Since FC were never reduced to below 3 log cfu.100 mL-1, the water did not adhere to guidelines for produce irrigation. Photo-repair following irradiation was investigated in river water using MP UV doses of 13 and 24 mJ.cm-2 and 3.5 kLux reactivating light, initially. Ultraviolet transmission was close to 50% and total coliform (TC) reduction exceeded 3 log, even at 13 mJ.cm-2. However, TC were reactivated from below 1 000 cfu.100.mL-1 to 3.93 and 4.41 log cfu.100 mL-1 for the 13 and 24 mJ.cm-2 treatments, respectively. A higher MP dose (40 mJ.cm-2) and a different treatment regime (2 x 20 mJ.cm-2) inhibited photo-repair (compared to 13 and 24 mJ.cm-2) but TC were always recovered to a final concentration surpassing 3 log cfu.100 mL-1, even under lower light intensities (1.0 to 2.0 kLux). In the current study UV irradiation did not produce water of acceptable standards for produce irrigation, mainly as a result of extremely poor water quality. However, on farm-scale, UV efficiency could be enhanced by improving water quality before irradiation. Also, stronger lamps that deliver higher UV doses may result in adequate disinfection, irrespective of water quality. Higher UV doses and the use of combination treatments (such as UV/Chlorine and UV/Peracetic acid) should be further investigated also to determine its disinfection efficiency and possible capability to inhibit post-disinfection repair. / AFRIKAANSE OPSOMMING: Varsproduk besproeiingswater vanuit Wes-Kaapse riviere bevat fekale kolivorme (FK) (Escherichia coli) in konsentrasies wat dikwels die voorgestelde limiet van 1 000 FK per 100 mL oorskry en hou `n gesondheidsrisiko vir verbruikers in. Plaasvlak ultraviolet (UV) bestraling bied verskeie voordele met verwysing na water dekontaminering, maar word selde aangewend in Suid-Afrika. Die doel van hierdie studie was om die gebruik van UV bestraling vir die dekontaminering van rivierwater, voor besproeiing, te ondersoek. Escherichia coli (E. coli) isolate is blootgestel aan lae-druk (LD) UV (4 mJ.cm-2) en UV/Waterstofperoksied (H2O2) (4 mJ.cm-2/20 mg.L-1) behandelings in Steriele Sout Oplossing (SSO). Isolaat variasie in reduksies is waargeneem en het gewissel tussen 1.58 tot 3.68 en 1.34 tot 3.60 log vir die UV en UV/H2O2 behandelings, onderskeidelik. In vergelyking met UV bestraling alleen was die UV/H2O2 behandeling (4 mJ.cm-2/20 mg.L-1) meer effektief teen sommige E. coli isolate. Geselekteerde isolate was meer sensitief tot hoër UV dosisse (8, 10 en 13 mJ.cm-2) en H2O2 konsentrasies (100 en 200 mg.L-1 met 4 mJ.cm-2), maar `n 3 log teikenreduksie was nie altyd haalbaar nie. Vir alle UV en UV/H2O2 behandlinge was die meeste weerstand deur `n omgewingsisolaat gebied. Verwysingsisolate behoort daarom nie aangewend te word vir die optimisering van UV-gebaseerde behandelingsparameters nie. By 10 mJ.cm-2 was beide `n ATCC verwysingsisolaat en `n omgewingsisolaat (ATCC 25922 en F11.2) betekenisvol minder gedeaktiveer in rivierwater as in SSO. Verbeterde waterkwaliteit het verhoogde inaktivering van die ATCC isolaat toegelaat. Die doeltreffendheid van LD UV (5, 7 en 10 mJ.cm-2) en medium-druk (MD) UV (13, 17 en 24 mJ.cm-2) bestraling is ook ondersoek deur watermonsters vanuit die Plankenburg Rivier te gebruik. Watermonsters was getrek en behandel op drie verskillende dae (Proewe 1 tot 3). Fisies-chemiese en mikrobiologiese kwaliteit van die water was deurentyd swak. Die FK konsentrasie het `n maksimum van 6.41 log kve.100 mL-1 bereik terwyl UV transmissie altyd laer as 38% was. Vir beide LD en MD UV bestraling het verhoogde dosisse gelei tot verbeterde dekontaminering, maar `n 3 log reduksie is slegs bereik toe MD UV lig gebruik is in Proef 1. Die effektiwiteit van die behandelings was afhanklik van waterkwaliteit en die eienskappe van die mikrobiese populasie in die water. Aangesien FK nooit tot onder 3 log kve.100 mL-1 verminder is nie het die water nie voldoen aan riglyne vir varsproduk-besproeiing nie. Fotoherstel na bestraling was ondersoek in rivierwater deur aanvanklik gebruik te maak van MD UV dosisse van 13 en 24 mJ.cm-2 en 3.5 kLux heraktiverende lig. Ultraviolettransmissie het byna 50% bereik en reduksie van totale kolivorme (TK) het 3 log oorskry, selfs by 13 mJ.cm-2. Totale kolivorme was egter geheraktiveer van onder 1 000 kve.100.mL-1 tot 3.93 en 4.41 log kve.100 mL-1 vir die 13 en 24 mJ.cm-2 behandelings, onderskeidelik. In vergelyking met 13 en 24 mJ.cm-2 het `n hoër MD dosis (40 mJ.cm-2) en `n veranderde bestralingstegniek (2 x 20 mJ.cm-2) fotoherstel onderdruk, maar TK was in elke geval geheraktiveer tot `n finale konsentrasie hoër as 3 log kve.100 mL-1, selfs onder laer intensiteit lig (1.0 tot 2.0 kLux). In hierdie ondersoek het UV bestraling nie water van aanvaarbare standaarde vir varsproduk besproeiing gelewer nie, hoofsaaklik as gevolg van swak waterkwaliteit. Nietemin, op plaasvlak mag die effektiwiteit van UV bestraling verhoog word deur waterkwaliteit voor bestraling te verbeter. Die gebruik van sterker lampe, om hoër UV dosisse te produseer, mag verder bydra tot voldoende dekontaminasie, ongeag van waterkwaliteit. Hoër UV dosisse en die gebruik van kombinasie behandelinge (soos UV/Chloor en UV/Perasynsuur) moet ook verder ondersoek word om die dekontaminasie effektiwiteit, en vermoë daarvan om heraktivering na dekontaminering te onderdruk, vas te stel.

Since Pecan Creek receives sewage wastes from an obviously inadequate disposal system, it seemed possible that it could receive pathogenic bacteria. The fact that these might be present in numbers sufficient to cause epidemics, provided the proper natural vectors were present, stimulated an interest in and the pursuance of this study.

Sampling data of many surface water bodies in Broward County tend to reveal abnormal levels of bacterial concentrations for total coliform, Escherichia coli and Enterococcus. Given the presence of septic systems in geohydrologically sensitive areas throughout the County, several studies (Morin 2005 and Bocca 2007) suggested a correlation in the high bacterial densities and the septic sites. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Thesis (MPH)--University of Limpopo, 2005 / Water and sanitation inadequacy is still an environmental health challenge in several regions worldwide and a billion people lack access to safe water, while 2.4 billion people have inadequate sanitation [2]. Assessment of water quality by its chemistry includes measures of elements and molecules dissolved or suspended in water. Commonly measured chemical parameters include arsenic, cadmium, calcium, chloride, fluoride, total hardness, nitrate, and potassium [16]. Water quality can also be assessed by the presence of waterborne microorganisms from human and animals’ faecal wastes. These wastes contain a wide range of bacteria, viruses and protozoa that may be washed into drinking water supplies [21]. Three villages were selected for water quality analysis, based on their critical situation regarding access to water and sanitation: namely, Matlou, Sekuruwe and Taolome villages, situated in the Mogalakwena Local Municipality within the Waterberg district of the Limpopo Province, South Africa. A proposal was written to the Province of North Holland (PNH) and was approved for funding to start with the implementation of those projects, with 20% of each village’s budget allocated for water quality research [26]. This was a cross sectional, analytical study to investigate the chemical and microbial quality of water in Matlou, Sekuruwe and Taolome villages. The study was also conducted to explore methods used by household members to store and handle water in storage tanks. Water samples were collected and analysed according to the standard operating procedures (SOPs) of the Polokwane Municipality Wastewater Purification Plant in Ladanna, Polokwane City of South Africa. The questionnaire used was adopted from the one used for cholera outbreak in the Eastern Cape Province of South Africa. Results show that water from all sources in all the villages had increased total hardness concentration. Water from the borehole in Matlou village had increased number of total coliform bacteria. There were increased total and faecal coliform bacteria in storage tanks samples from Matlou village. Water samples from reservoirs in Sekuruwe and Taolome villages did not test positive for any microbial contamination. Water from xiv informally connected yard taps in Sekuruwe village had increased total coliform bacteria, while increased total and faecal coliforms were found in households’ storage tanks. Water samples from communal taps in Taolome village had minimal number of total coliform bacteria, while water from storage tanks had both increased total and faecal coliform bacteria. Matlou village was the only place with increased nitrate concentration at the households’ storage tanks. While all the villages had microbial contamination, Taolome village had the least number of coliform bacteria in water samples from households’ storage tanks as compared to Matlou and Sekuruwe villages. It is concluded that water from sources supplied by the municipalities are safe to be consumed by humans while water from informally connected taps and households’ storage tanks are not safe to be used without treatment. It is recommended that a health and hygiene education package be prepared for all the villages, so that handling of water from the main source into their storage tanks can be improved. Secondly, it is recommended that water in all sources be treated for total hardness and water in storage tanks in Matlou village be treated for nitrate. Thirdly, it is recommended that water be accessed everyday of the week, so that people do not use unsafe water supplies. / The Province of North Holland, Netherlands.

We explain a new method of detecting non point source fecal contamination using a PCR based method called Touchdown Polymerase Chain Reaction (TD-PCR). Using genetic markers particular to general, ruminant and human Bacteroides- Prevotella genes, we identified presence in both fresh and salt water environments. Water samples from four sites were collected at approximate 2-week intervals for a year. Samples were analyzed for total coliforms, fecal coliforms, E. coli, and the presence of general, ruminant and human Bacteroides-Prevotella markers. We compared the odds of recovering each PCR marker between sites. We investigated the relationship between rainfall and recovery of PCR markers. Finally, we compared the sensitivity of the PCR methods to standard public health methods. / Graduation date: 2003

With congressional passage of the BEACH Act in October of 2000, Coastal and Great Lakes states were mandated to assess coastal recreation waters for the application of ambient water quality standards. This research encompasses two components involved in applying the BEACH Act statues to Oregon. The first component was to select beach sites in Oregon. The second component involves applying bacterial recreational water standards to select Oregon beaches. Using the guidelines provided by the United States Environmental Protection Agency (EPA), this study develops a method to appraise Oregon marine recreational waters taking into account the following factors: use, available information, pollution threats, sanitary surveys, monitoring data, exposure considerations, economics, and development. In an effort to protect the public from swimming-associated illness attributable to microbial pollution, 24 beaches were identified in Oregon. Of these, 19 beaches were classified as tier 1, or high priority, and five sites were classified as medium priority, or tier 2. Future studies should be directed at ascertaining the beach lengths utilized by Oregon marine recreators since this is an important parameter in targeting bacterial monitoring. Ongoing monitoring of these 24 sites is warranted and new information could be used to update beach tier levels in Oregon. In the second phase of this study, bacterial monitoring data was used for comparison to recreational water quality standards. In October of 2002, the Oregon Department of Environmental Quality (ODEQ) sampled 26 beaches for enterococci and Escherichia coli (E. coli) densities. Of the water sampled from all 26 beach sites, nine exceeded s single sample maximum density of 104 enterococci colony forming units (cfu) per 100 milliLiters (mL). The Oregon beach with the highest exceedance occurred at Otter Rock's South Cove where the enterococci concentration was 4352 most probable number (MPN)/100 mL. A comparison of the 26 sampled beaches to ODEQ's estuarine E. coli standard of 406 organisms/100 mL resulted in two beaches with exceedances. Otter Rock at South Cove had the highest E. coli concentration at 1850 MPN/100 mL. Based on the limited data used in this study, should Oregon adopt the enterococci standard in lieu of the current ODEQ estuarine E. coli standard, more beaches will have exceedances of the recreational water standard. Additional bacterial monitoring is warranted to further characterize the nature and extent of the problem in Oregon. To protect the health of the marine recreating public, future Oregon marine water quality studies should delineate the "no swim" zone around creeks and model the impacts of rainfall on beach sites. / Graduation date: 2004

Few studies, and none in Oregon, have examined the presence and change of water quality parameters over time in popular natural swimming areas. This information is necessary to better understand water quality and risk of illness from either fecal contamination or cross-infection from other swimmers. The purpose of this study was to quantitatively measure bacterial and selected physical and chemical parameters, and collect background information for changes to the current state water quality criteria. Five natural swimming areas in Linn, Benton and Polk counties were chosen and sampled biweekly for physical, chemical, and bacterial parameters over a nine week period from June 28 to August 31, 1996. The results showed differences in bacterial levels over the sampling period which often varied by degrees of magnitude between sites. For example, the range in Escherichia coli levels was between 0 and 1000 colonies/100mL sample for two sites on the same sampling day. Similarly, the range in fecal coliform levels was between 5 and 500 colonies/100mL sample. The daily colony counts at each site exceeded the state standards at least 10% of the time for E. coli and 21% of the time for fecal coliform. At the most popular swimming site, Montieth Park. the fecal coliform regulatory levels were exceeded 79% of the time and E. coli levels were exceeded 42% of the time. This may be due to turbidity, high bather load, or a broken sewer line. The 30 day log mean of these values shows consistently elevated fecal coliform problems only at Montieth Park. For the other sites, the log means did not exceed the state and federal regulatory limits for fecal coliform or E. coll. This raises questions about which estimates should be used to assess public health risk. None of the other parameters in this study were correlated with bacterial counts, so it appears that none of these factors is solely responsible for elevated bacterial levels. Further testing should be done at Montieth Park to determine the cause of the elevated fecal coliform levels. Any follow-up studies should test several different indicator organisms in addition to E. coli for comparison and assessment of their relationship to public health risk. / Graduation date: 1997

Thesis (MSc Food Sc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Over the past two decades, there has been an increase in the use of water sources for irrigation, as well as an increase in Escherichia coli outbreaks linked to fresh produce. The full extent and type of E. coli contamination present in natural water sources is unknown and the contamination sources have also not been confirmed. The aim of this study was to enumerate and characterise E. coli from both irrigation water and potential contamination source sites. Total coliform and E. coli counts found in contamination source sites were as high as log 7.114 and log 6.912 MPN.100 mL-1, respectively. Total coliform and E. coli counts for irrigation sites were lower, with maximum counts of log 5.788 and log 5.768 MPN.100 mL-1, respectively. It was found that more than one third (5/14 = 35.71%) of the irrigation sites had E. coli counts exceeding the guidelines (<1 000 counts.100 mL-1) for ‘safe’ irrigation water for fresh produce (<1 000 counts.100 mL-1) as set by the Department of Water Affairs (DWA) and World Health Organisation (WHO), making the water unsuitable for the irrigation of fresh produce. Phylogenetic subgroups (A0, A1, B1, B22, B23, D1 and D2) and the MALDI Biotyper system (PCA dendrogram) were used to create a fingerprint of each E. coli isolated from the environment. These were then used to link E. coli strains from irrigation water to their most probable contamination origin. Escherichia coli population structure was found in this study, to be better suited for linking E. coli strains from irrigation water to their most likely source, than just applying the phylogenetic grouping. The MALDI Biotyper data in combination with the phylogenetic subgroup assignment was then used to group similar strains and link E. coli from irrigation water to their contamination sources by comparing population structures. Strains isolated from surface and groundwater showed similar distribution patterns, but groundwater strains showed a population structure more indicative of porcine and bovine origin, while surface water showed population characteristics which could not be used to make conclusive links between the irrigation water and suspected contamination sources. When investigating the population structures of individual sample sites, it was found that phylogenetic subgroups A0, A1 and B1 frequently made up the bulk of the E. coli population. It was also found that linking individual irrigation sites to contamination sources was successful, as irrigation site Berg-2 was found to have a similar population structure to contamination source site Plank-1 which represents human pollution from an informal settlement. This led to the conclusion that Berg-2 was being contaminated by human pollution, most probably from an informal settlement. Upon further investigation it was found that Berg-2 is downstream of an informal settlement, proving that E. coli population structure is a successful means of microbial source tracking (MST). Virulence factors of the 153 E. coli isolated during the study were identified and the potential risk associated with using the investigated irrigation water for irrigation of fresh produce, was determined. Two enteropathogenic E. coli (EPEC) strains were isolated from the irrigation water, one from the Plankenburg River water, and the other from a borehole in the Drakenstein area. The latter indicates that borehole water is not as safe as was once thought, and that there are bacterial contaminants finding their way into groundwater. The occurrence of an EPEC strain in river water shows that neither ground nor surface water is guaranteed to be safe, and that treatment of water being used for the irrigation of fresh produce should be implemented. / AFRIKAANSE OPSOMMING: Oor die afgelope twee dekades was daar nie net 'n toename in die gebruik van alternatiewe waterbronne vir besproeiing nie, maar ook 'n toename in uitbrake van Escherichia coli uitbrake wat aan vars produkte gekoppel kan word. Die tipe E. coli-besmetting wat in natuurlike waterbronne teenwoordig is, is onbekend en die besmettingsbron is ook nog nie bevestig nie. Daarom was die doel van hierdie studie om die voorkomssyfer van E. coli van beide besproeiingswater en potensiële kontaminasiebronne te bepaal, asook om die E. coli te karakteriseer. Totale kolivorme en E. coli-tellings wat in kontaminasiebronne gevind is, het ‘n maksimum van log 7,114 en log 6,912 MPN.100 mL-1 onderskeidelik bereik, terwyl die totale kolivorme en E. coli-tellings vir besproeiingswater laer was, met 'n maksimum van log 5,788 en 5,768 MPN.100 mL-1, onderskeidelik. Dit is bevind dat meer as 1/3 (5/14 = 35,71%) van die besproeiingswaterbronne meer E. coli bevat as wat toegelaat word in die riglyne vir "veilige" besproeiingswater vir vars produkte (<1 000 fekale koliforme.100 mL-1) wat deur die Departement Waterwese (DWA) en die Organisasie vir Wêreldgesondheid (WHO) aanbeveel word. Filogenetiese subgroepe (A0, A1, B1, B22, B23, D1 en D2) en die ‘MALDI Biotyper’-stelsel (PKA dendrogram) is gebruik om unieke profiele vir elke geïsoleerde E. coli te skep. Dié profiele is daarna gebruik om E. coli-stamme van besproeiingswater te koppel aan die mees waarskynlike oorsprong van kontaminasie. Daar is in hierdie studie bevind dat die E. coli-populasiestruktuur beter geskik was vir die koppeling van E. coli-stamme van besproeiingswater na hul mees waarskynlikste bron, as net die toepassing van die filogenetiese groepering. Dit was toe gevind dat E. coli wat uit oppervlak- en grondwater geïsoleer is, soortgelyke verspreidingspatrone het, maar grondwaterstamme se bevolkingstruktuur is meer aanduidend van fekale besmetting deur varke en beeste, terwyl oppervlakwater se bevolkingseienskappe nie duidelik genoeg was om ‘n gevolgtrekking oor moontlike bronne van besmetting te maak nie. Toe die populasiestruktuur van die individuele bemonsteringspunte ondersoek is, is daar bevind dat die filogenetiese subgroepe A0, A1 en B1 dikwels die meeste tot die E. coli bevolking bydra. Daar is ook bevind dat die koppeling van isolate in individuele besproeiingswaterbronne met hul mees waarskynlike bronne van kontaminasie suksesvol was. Besproeiingswater van Berg-2 het 'n soortgelyke populasiestruktuur as Plank-1 wat beskou is as ‘n kontaminasiebron. Dit het gelei tot die gevolgtrekking dat Berg-2 heel waarskynlik deur menslike besoedeling beïnvloed word, soos Plank-1, en dat daar moontlik ook ‘n informele nedersetting by Berg-2 betrokke is. Na verdere ondersoek is gevind dat Berg-2 inderdaad ook stroomaf van 'n ander informele nedersetting geleë is, wat bewys dat die E. coli-populasiestruktuur 'n suksesvolle manier is om E. coli kontaminasie te verbind met besproeiingswater. Patogeniese faktore, wat in E. coli voorkom en maagkieme veroorsaak, is vooraf getoets in elkeen van die 153 E. coli-isolate wat tydens die studie geïdentifiseer is. Twee ‘enteropathogenic’ E. coli (EPEC)-stamme is uit die besproeiingswater geïsoleer: een uit die Plankenburgrivier (Plank-3), en die ander uit 'n boorgat in die Drakenstein-gebied (Boorgat A1). Hierdie inligting dui aan dat boorgatwater nie so veilig is as wat voorheen vermoed is nie, en dat bakteriese kontaminasie wel vookom wat nie alleen die grondwater besmet nie, maar ook daarin oorleef. Die voorkoms van die EPEC-stamme in hierdie studie is ‘n aanduiding dat beide grond- en opppervlakwater ewe gevaarlik kan wees, en dat daar dus geen waarborg vir die veiligheid van die water is nie. Die behandeling van grond- en oppervlakwater, wat vir die besproeiing van vars produkte gebruik word, moet daarom ernstig oorweeg word om moontlike uitbrake van E. coli op vars produkte te verhoed.

Graduation date: 2003 / Best scan available on figures. Original figures are dark.

Thesis (DTech (Biomedical Technology))--Cape Peninsula University of Technology, 2008. / Includes bibliographies. Also available online.