No description available.

Master of Science / Department of Biological & Agricultural Engineering / Naiqian Zhang / Four permittivity probes have been developed and tested to measure contaminants in water and in biodiesel fuel. An impedance meter was also used to measure the same contaminants. The pollutants measured in water were nitrate salts (potassium nitrate, calcium nitrate, and ammonium nitrate) and atrazine. The contaminants measured in biodiesel were water, glycerol, and glyceride. Each sensor measured the gain and phase of a sample with a known concentration of one of these pollutants. The resulting signals were analyzed using stepwise regression, partial least squares regression, artificial neural network, and wavelet transformation followed by stepwise regression to predict the concentration of the contaminant using changes in the gain and phase data measured by the sensor. The same methods were used to predict the molecular weight of the nitrate salts. The reliability of the probes and the regression methods were compared using the coefficient of determination and the root mean square error. The frequencies selected using stepwise regression were studied to determine if any frequencies were more useful than others in detecting the contaminants. The results showed that the probes were able to predict the concentration and the molecular weight of nitrates in water very accurately, with R2-values as high as 1.00 for the training data and 0.999 for the validation data for both concentration predictions and molecular weight predictions. The atrazine measurements were somewhat promising, the training R2-values were as high as 1.00 in some cases, but there were many low validation values, often below 0.400. The results for the biodiesel tests were also good; the highest training R2-value was 1.00 and the highest validation R2-value was 0.966.

A study was conducted in two sites: one at an electricity storage facility belonging to the Swaziland Electricity Board (SEB) and the other at a facility that belongs to its treated pole supplier, the Thonkwane wood creosote treatment plant. The drainage system of these sites leads to surface waters in rivers. This is a cause of concern since creosote contains polycyclic aromatic hydrocarbons (PAHs), which are listed as priority pollutants by the US Environmental Protection Agency. They have toxic, mutagenic and carcinogenic effects and as a result they pose a threat to human life and the environment. No previous studies have been done on PAHs in Swaziland. The main objective of this study was to determine the impact of the SEB storage facility and the creosote treatment plant by investigating the extent of PAHs in surrounding environments (soil, sediments and surface waters). Preliminary studies were undertaken on the storage facility and the creosote treatment plant. No PAHs were detected from the pole storage facility; therefore the creosote wood treatment facility was selected as the ideal site at which to conduct the research. Soil samples were collected from depths 15 cm and 60 cm at points around the creosote plant, including effluent discharge points. The samples were extracted by solid-phase micro extraction (SPME) and analysed by GC/MS. The GC/MS, incorporating a solid phase micro extraction step, provided detection limits ranging from 0.12 μg/g to 20.08 μg/g. The pollution patterns in the study site were assessed using cluster analysis and principal component analysis. Most of the 16 US EPA-listed priority pollutants were detected from the creosote wood treatment facility. PAHs such as anthracene, fluorene, naphthalene and fluoranthene were dominant in all the sampling sites. The compounds occurred in very high concentrations (0.64, 0.46, 0.27 and 0.26 mg/kg respectively). These compounds are found in pure creosote as determined in the sample taken from the Thonkwane creosote tank site. The highest concentration of PAHs was observed in the soil samples taken next to the road site. The concentrations of the identified PAHs were above the acceptable minimal level allowed in soil by the US EPA and Swaziland Environment Authority (SEA). The levels of the PAHs are also above the recommended US EPA limit in soil, which is 0.1 mg/kg. The results indicated that significant soil pollution was taking place in some of the sampling sites. The top layer (0, 15 cm) contained many PAHs at high levels whilst the 60 cm layer had a lower number of PAHs which were also in low concentrations. This provided an indication that there is no downward movement of PAHs from the surface layer to underground layers. The potential exists for contamination of surface waters when there is runoff from the project area. This is a cause of concern, since both the creosote treatment plant and areas outside the facility are contaminated. Therefore, the site has to be cleaned up, preferably by using a phytoremediation technique. / Environmental Sciences / M. Sc. (Environmental Science)

Bacterial water pollution is a significant problem because it is associated with reduction in the ‘quality’ of water systems with a potential impact on human health. Faecal indicator bacteria (FIB) are usually used to monitor the quality of water, and to indicate the presence of pathogens in water bodies. However, enumeration alone does not enable identification of the precise origin of these pathogens. This study aimed to monitor the quality of bathing water and associated fresh water in and out of the ‘bathing season’ in the UK, and to evaluate the use of microbial source tracking (MST) such as the host-specific based polymerase chain reaction (PCR) and quantitative PCR (qPCR) to recognize human and other animal sources of faecal pollution. The culture-dependent EU method of estimating FIB in water and sediment samples was performed on beach in the South Sands, Kingsbridge estuary, Devon, UK- a previously ‘problematic’ site. FIB were present at significant levels in the sediments, especially mud, as well as fresh water from the stream and pond flowing onto South Sands beach. However, the quality of bathing water was deemed to be ‘good’ and met with the EU bathing water directive 2006. Using MST it was possible to successfully classify the nature of the source from which the bacteria came. PCR was applied to detect the Bacteroides species 16S rRNA genetic markers from human sewage and animal faeces. All water and sediment samples displayed positive results with a general Bacteroides marker indicating the presence of Bacteroides species. Host-specific PCR showed the human Bacteroides genetic marker only in the sediment of the stream. However, limitations in the ‘types’ of probes available and in the persistence of these markers were identified. Thus, novel dog-specific Bacteroides conventional PCR and qPCR primer sets were developed to amplify a section of the 16S rRNA gene unique to the Bacteroides genetic marker from domestic dog faeces, and these were successfully used to quantify those markers in water samples at a ‘dog permitted’ and ‘dog banned’ beach (Bigbury-on-Sea, Devon, UK). Generic, human and dog Bacteroides PCR primer sets were also used to evaluate the persistence of Bacteroides genetic markers in controlled microcosms of water and sediment at differing salinities (< 0.5 and 34 psu) and temperature (10 and 17 ºC). The rates of decline were found did not differ significantly over 14 and 16 days for the water and sediment microcosms, respectively. Beach sediments which were studied in this project may act as a reservoir for adhesive FIB, and this was confirmed using fluorescence in situ hybridisation (FISH). The similarity in the persistence of these Bacteroides 16S rRNA genetic markers in environmental water and sediment suggests that viable but non-culturable (VBNC) Bacteroides spp. do not persist in the natural environment for long. Therefore, 16S rRNA genetic markers can be of value as additional faecal indicators of bathing water pollution and in source tracking. Thus, in this study MST methods were successfully used and in future applications, dog-specific primer sets can be added to the suite of host-specific Bacteroides genetic markers available to identify the source(s) of problem bacteria found on failing beaches.

Mine abandonment and the discharge of contaminated mine water is recognised globally as a major source of surface water and groundwater pollution. Contamination generally arises from the oxidation of sulphide minerals, principally pyrite, by the mining process, and the subsequent chemical reactions can lead to the discharge of mineralised, often acidic, iron, and sulphate rich waters. In many historically mined river catchments, mine water discharge is the main cause of poor water quality. Within the UK, managing the legacy of abandoned mines is one of the principal challenges presented by modern environmental legislation, particularly the EU Water Framework Directive, a challenge that is exacerbated by the diverse and widespread nature of historical mining. The impact and hazard associated with abandoned mining in one of the UK’s most intensively mined regions, the Almond River Catchment, Scotland, was examined via: 1) a detailed GIS mapping and investigation of historical mining processes in the catchment, 2) mine site discharge sampling, 3) detailed site investigations, 4) geochemical modelling of four mine waste sites and 5) analysis of temporal and spatial river water quality in the catchment. The results are then brought together to produce a catchment scale mine water hazard map. Mapping has identified over 300 mine sites in the catchment including coal, oil shale and ironstone mine wastes and flooded coal and oil shale mines. The historical development of oil shale retort methods has been shown to have an impact on potential hazard. Sampling of discharge waters from the different mining activities, in conjunction with detailed mineralogical analysis and geochemical modelling at the four mine waste sites has characterised the main hazards. Ironstone and pyrite bearing coal mine wastes discharge waters with highly elevated Fe and sulphate concentrations, up to 160mgl-1 and 1900mgl-1 respectively, due to extensive pyrite oxidation and acid generating salt dissolution (principally jarosite). Coal mine wastes show variable mineralogy, due to the diverse nature of coal bearing strata, and discharge waters with variable chemistry. Oil Shale mine wastes are generally depleted in pyrite due to historic processing and discharge low sulphate waters with moderately elevated Fe concentrations, up to 5mgl-1. Flooded coal mines discharge sulphate dominant alkaline waters, due to the availability of carbonate minerals in the mine complex, with elevated Fe concentrations, up to 50mgl-1, while flooded oil shale mines discharge waters with moderately elevated Fe concentrations, up to 4mgl-1, due to lower pyrite content in mine strata and reduced availability of oxygen related to mine abandonment age. Once in the surface water environment iron and sulphate display significant concentration-flow dependence: iron increases at high flows due to the re-suspension of river bed iron precipitates (Fe(OH)3); sulphate concentrations decrease with increased flow as a result of dilution. Further examination of iron and sulphate loading at low flows indicates a close correlation of iron and sulphate with mined areas; cumulative low flow load calculations indicate that coal and oil shale mining regions contribute 0.21 and 0.31 g/s of iron, respectively, to the main Almond tributary. Decreases in iron loading on river sections demonstrate the deposition and diffuse storage of iron within the river channel. This river bed iron is re-suspended with increased flow resulting in significant transport of diffuse iron downstream with load values of up to 50 g/s iron. Based on this hazard classification, a catchment scale mine water hazard map has been developed. The map allows the prioritisation of actions for future mine water management.

No description available.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management