The research provides data of pH and conductivity, some anions (e. g. fluoride, chloride, bromide, nitrate, phosphate and sulphate), monovalent cations (e. g sodium, ammonium and potassium), divalent cations (e. g calcium and magnesium) heavy metals (e. g. iron, copper, zinc, nickel, cobalt, cadmium and manganese) and organic compounds – from water samples of rivers of Brunei Darussalam, namely, Brunei River, Belait River, Tutong River and Temburong River. The higher values of certain parameters with respect to the acceptable standard limits for river water indicate the pollution in river water samples of the study area, make the waters unsuitable for various applications and do pose a human health hazard. The pH levels in Brunei Darussalam is quite reassuring and mostly safe. Although there are some stretches of rivers that show slightly lower levels of pH, there is no cause for any alarm as these waterways are not sources of drinking water. As for anions and cations, the only anion of significant levels detected in Brunei Rivers is chloride whereas only monovalent cation detected in significant levels, is sodium. The concentrations of chloride and sodium ions are below the standard concentrations. Brunei Rivers are still free from chloride and sodium pollution. For heavy metals, only iron is detected in Brunei Rivers. Brunei being a oil based country experiments were done to identify levels of a numbers of significant toxic organic compounds, including, toluene and benzene which have been detected in the waters of the oil mining district of Belait District but are within normal limits. The use of a photolytic cell system to achieve the photodegradation of benzene, toluene, ethylenediaminetetra-acetic acid (EDTA) and the surfactant – hexadecyltrimethyl-ammonium bromide (C19H42NBr) is reported. The system has been optimised by investigating the effects of the addition of hydrogen peroxide (H202) as an oxidant and the addition of titanium dioxide (TiO2) as a catalyst. The results show that the photolytic system can be used to achieve >99% degradation of organic contaminants. The research also includes a final chapter on management system which covers water protection, pollution control and solid waste management in Brunei. In addition to investigating various factors of the solid waste management in Brunei, the researcher has also exposed some of the weaknesses that need immediate addressing. Various measures have been suggested to make Brunei's water more efficient. Moreover, ways of preserving the high quality of Brunei's water figures in this chapter.

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Made available in DSpace on 2016-06-02T19:29:46Z (GMT). No. of bitstreams: 1 4357.pdf: 3085998 bytes, checksum: 2ad756e1438590445445284d48e7a5a0 (MD5) Previous issue date: 2012-03-12 / Financiadora de Estudos e Projetos / This study aims to characterize the hydromorphological variables that structure the ichthyofauna and see if there is difference in the estimated species richness and species richness of families and trophic groups between the rivers and streams sampled and between the headwaters of the Araguaia and Tocantins basins and different environments sampled, floodplain and regions of the head. The samples were taken from 30 watercourses, of which 12 belong to the basin of the Tocantins and Araguaia basin to 18. For analysis of the ichthyofauna were considered species richness and abundance of individuals of families and trophic groups. The variables considered were pH, conductivity, dissolved oxygen, water velocity, width, depth, light and turbidity. The results showed that the location of watercourses in the floodplain of the Araguaia River basin or in the regions of the head independent of the basin was the main factor that defines both the number of species and the similarity of the ichthyofauna. The streams included in the flood plain of the Araguaia basin that are favored by the heterogeneity of the habitat had the highest number of species. Instead, the head of watercourses, shallow, narrow and with the presence of rocks, which are characterized by reduced habitat had low values of richness of the fauna, which was structured by varying pH and conductivity. On the other hand, as the species richness of families and trophic groups no significant difference between the headwaters of the Araguaia and Tocantins river basins, however between different environments, headboard and plain, the basin of the Araguaia River, this difference was significant. Among the regions of the headwaters of the Araguaia and Tocantins river basins, both families and trophic groups are more species-rich at the points of the head of the Tocantins, because, despite their similar characteristics, the majority of the data points presented in the headwaters of the Tocantins be more conservative with respect to the presence of riparian vegetation. On the other hand, the species richness of families and trophic groups in the different environments sampled in the Araguaia basin, plain and headboard, showed that the lowland region is richer in species, which presents important feature, the heterogeneity of habitat that offers great diversity of shelter and food resources. / Este trabalho tem como objetivo caracterizar as variáveis hidrogeomorfológicas que estruturam a ictiofauna e verificar se existe diferença quanto à riqueza de espécies e a riqueza de espécies das famílias e grupos tróficos entre os rios e riachos amostrados e entre as cabeceiras das bacias Tocantins e Araguaia e a cabeceira e a planícei da bacia do Araguaia. As amostragens foram realizadas em 30 cursos d água, dos quais 12 pertencem à bacia do Tocantins e 18 à bacia do Araguaia. Para as análises da ictiofauna foram consideradas a riqueza de espécies e a abundância de indivíduos das famílias e dos grupos tróficos. As variáveis consideradas foram pH, condutividade, oxigênio dissolvido, velocidade da água, largura, profundidade, luminosidade e turbidez. Os resultados mostraram que a localização dos cursos d água na planície de inundação da bacia do rio Araguaia ou nas regiões de cabeceira independente da bacia foi o principal fator que definiu tanto o número de espécies quanto a similaridade da ictiofauna. Os cursos d água inseridos na planície de inundação da bacia do Araguaia que são favorecidos pela heterogeneidade do habitat apresentaram maior número de espécies. Ao contrário, os cursos d água de cabeceira, rasos, estreitos e com presença de rochas, que são caracterizados pela redução de habitat apresentaram baixo valores de riqueza da ictiofauna, a qual foi associada às variáveis pH e condutividade. Por outro lado, quanto à riqueza de espécies das famílias e dos grupos tróficos não existe diferença significativa entre as cabeceiras das bacias Tocantins e Araguaia, entretanto entre os diferentes ambientes, cabeceira e planície, da bacia do rio Araguaia, essa diferença foi significativa. Entre as regiões das cabeceiras das bacias Tocantins e Araguaia, tanto as famílias quanto os grupos tróficos são mais ricos em espécies nos pontos de cabeceira da bacia do Tocantins, pois, apesar de apresentarem características semelhantes, a maioria dos pontos amostrados na cabeceira do Tocantins apresentou ser mais conservada com relação à presença da vegetação ripária. Por outro lado, a riqueza de espécies das famílias e dos grupos tróficos nos diferentes ambientes amostrados na bacia do Araguaia, planície e cabeceira, mostrou que a região da planície é mais rica em espécies, a qual apresenta importante característica, a heterogeneidade do habitat, que oferece grande diversidade de abrigos e recursos alimentares.