ABSTRACT The tropical and subtropical nearshore marine environments of Queensland, Australia sustain diverse and unique marine wildlife. Continuous population growth and land-use changes along the Queensland coastline are known to exert numerous anthropogenic pressures on these marine ecosystems, including the delivery of high sediment loads. Sediments also provide a transport pathway for persistent organic pollutants (POPs) from rural and urban catchments into the marine environment. While such pollutants are known to be elevated in marine sediment and biota from nearshore areas in Queensland, their input and distribution pathways, as well as exposure and associated risks to wildlife populations are only partially understood. Mounting evidence suggests that POPs may contribute to population declines in marine wildlife species; however, limited information is available regarding the accumulation and effects of these contaminants in endangered or threatened marine turtles. This study aimed to redress some of these information gaps using a case study approach in marine turtle habitats of Moreton Bay, and other embayments in Queensland. Among persistent organic pollutants (POPs), dioxins (polychlorinated dibenzo-p-dioxins; PCDDs) and to some extent also dioxin-like PCBs (polychlorinated biphenyls; PCBs) were found to be widespread and often present at elevated (ppb) levels in surface sediments from Moreton Bay. However, while PCDD/F toxic equivalencies (TEQs) are above international (Canadian) sediment quality guidelines at numerous sites in Moreton Bay, in general TEQs across the Bay are relatively low compared to those from contaminated locations near dense industrial activities. POP contamination in surface sediments across Moreton Bay was investigated by a combination of GIS spatial mapping, geostatistical and traditional statistical modalities. High spatial variability and complex spatial distribution patterns were revealed. High resolution GIS kriging model outputs from the mid to southern Bay facilitated identification of distinct sediment contamination zones, with highest PCB and PCDD/F levels present in nearshore locations, associated with nearby river systems. While primarily governed by organic carbon, a multitude of physical, chemical and hydrological factors were identified to influence the spatial variance of PCDD/F concentrations. The main parameters governing PCDD/F spatial distribution were identified as sediment geochemistry, water depth and anthropogenic alterations of the physical environment and, together, all quantifiable explanatory variables (including hydrodynamic flushing) explained ≈75% of spatial PCDD/F variance. Together, the interaction of these parameters results in complex distribution patterns and highly variable concentrations even among neighbouring sites of 1-3 km resolution. These results suggest that prediction models of POP distributions in the nearshore marine environment may require high-resolution validation, and highlights that the design of low resolution monitoring strategies can have profound impacts on the reliability of contaminant information or any subsequent extrapolations. This knowledge and methodology can be utilised to optimise on-going and future near-shore sediment monitoring programs both locally and in other regions around the world. Using the spatial distributions of dioxin-like contaminants within sediments, this study provided an opportunity to assess field-based relationships between habitat contamination and local marine biota contamination. Detectable levels of PCDD/Fs and dioxin-like PCBs were measured in all green, hawksbill, loggerhead and flatback marine turtle tissues. POP concentrations in sediments were found to significantly correlate with those in the herbivorous green turtle from different sediment contamination zones. These findings demonstrate that sediments represent an important secondary contaminant source and lead to redistribution of POPs to the marine food chain. POP concentrations and TEQs clearly increased from sediment to turtles as well as with increasing trophic levels in marine turtle species. The results from this study demonstrate that the extent of sediment contamination within foraging habitats governs marine turtle exposure, while, trophic status and to some extent age influence contaminant exposure within a particular contamination zone. Despite the relatively low TEQ in sediments from Moreton Bay, TEQ levels in green turtle sub-populations foraging from near-shore locations and higher trophic loggerhead and flatback turtles are similar or elevated compared to those reported for other marine wildlife from Moreton Bay and elsewhere, even compared to higher trophic species from locations impacted by dense industrial activities. High bioaccumulation potential of 2,3,7,8-PCDD/F and dioxin-like PCBs compounds were estimated for green turtles using biota to sediment accumulation factors. Selective accumulation of toxicologically more potent (i.e. lower chlorinated) PCDD/Fs was observed for higher trophic marine turtles, resulting in increasing TEQs for the carnivorous species. Biomagnification was also observed for some non-2,3,7,8-substituted dioxin congeners which typically do not accumulate in most biota. These results are proposed to be due to relatively high accumulation efficiency and/or low metabolic capacity for these POP compounds in marine turtles. These findings are also hypothesised to reflect temperature dependant, greater bioavailability of hydrophobic chemicals in sub-tropical and shallow marine systems. An additional pilot study revealed that in contrast to PCDD/Fs and PCBs, levels of persistent flame retardants (polybrominated diphenyl ethers; PBDEs) were relatively low in marine turtles and other marine species (dugong, fish and shellfish) from Moreton Bay. This suggests relatively low level input of these more recent industrial products into the marine environment. However, as elevated levels of PBDEs have been reported in blood from the general population of Australia, ongoing transport from the terrestrial to the marine system and redistribution of these contaminants, similar to PCDD/F and PCBs, would be expected to occur into the future. Limited information is available regarding the sensitivity of reptiles to and effects of POPs, however, studies have shown that reptiles are sensitive to POPs albeit with uncharacterised relative potency. In the absence of robust toxicological information for reptiles or marine turtles, the potential risks associated with PCDD/F and PCB exposure of Queensland turtle populations was evaluated using toxicity for sensitive biological endpoints observed in mammals and birds. Using probabilistic methodology for marine turtles from Queensland, the body burden of up to 31% and 55% of green and loggerhead turtles, respectively, are above the threshold levels where the most sensitive physiological effects are observed in mammals and birds. While this evaluation illustrates that the contaminants investigated have the potential to impact on the health of marine turtle populations, it must be highlighted that it is compromised by the lack of species-specific (and in this case, class-specific) information, the uncertainty of which is often considered to represent a factor of at least 10. The findings of the present study indicate that exposure to POPs has the potential to adversely affect the health of Queensland’s marine turtle populations, and highlight the need for robust information on reptile specific sensitivity to these compounds.

Polychlorinated-p-dibenzo dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) (collectively termed ‘dioxins’) and polychlorinated biphenyls (PCBs) are three groups of persistent organic pollutants (POPs) ubiquitous in the environment due to their emission from numerous sources, high persistency and a propensity to be transported long distances. These compounds bioaccumulate in animal tissue, biomagnify through the food web and are toxic to humans and wildlife at relatively low concentrations. Humans may be exposed to POPs via ingestion, inhalation and dermal absorption, however, for the general population, approximately 90% of the total exposure occurs through intake of contaminated food particularly from lipid rich products, including seafood. An Australian national study highlighted that, similar to many other countries, seafood contributes a major proportion to dioxin and PCB exposure of Australians. As typical for national studies, the exposure assessment utilised contaminant concentrations in retail (sea)food and consumption information based on national dietary surveys. The risk assessment showed that the Australian population on the whole has a very low risk of exposure to dioxins through food. However, more than 80% of the Australian population lives within 50 km of the coast, where recreational, cultural and/or subsistence fishing of local seafood is prominent, potentially from areas with elevated PCDD/F and PCB concentrations. Through analysis of local seafood contamination and community seafood consumption patterns, this study assessed PCDD/F and PCB exposure for a coastal subpopulation in Moreton Bay, Queensland who consume locally caught seafood from an area with elevated PCDD/F and PCB concentrations but relatively low (background) toxic equivalency (TEQDP) in sediments, which is typical for Australian nearshore marine systems. Despite low sediment TEQDP levels, due to the dominance of octachlorodibenzo-p-dioxin (which is considered less potent compared to the most toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin), elevated TEQDP concentrations were present in local seafood. In particular higher trophic fish species and some traditional seafood were found to contain TEQDP above current EU action and maximum limits. This highlights the efficiency of species specific contaminant uptake, bioaccumulation and biomagnification processes, which can result in accumulation of higher toxic dioxin and PCB congeners in biota. In contrast, concentrations of most organochlorine pesticides and flame retardants (polybrominated diphenylehters (PBDEs)) were relatively low in seafood from Moreton Bay. For fish, uptake of highly lipophilic contaminants, such as PCDD/Fs and PCBs occurs predominantly via food (biomagnification) and respiratory processes (bioconcentration) followed by selective accumulation of the more toxic, lower chlorinated 2,3,7,8 PCDD/F congeners. This study discovered that physical contact with sediment and dermal absorption of lipophilic contaminants also represents an important exposure pathway for sediment dwelling fish, resulting in higher lipid normalised PCDD/F, PCB and TEQ levels (up to 8, 5 and 3 fold) in skin compared to muscle tissue. PCDD/F and PCB congener profiles differed between muscle and skin suggesting biomagnification and skin absorption as the respective predominant uptake pathways for these tissues. Dermal uptake was estimated to contribute up to 46% to the total TEQDP load on a lipid basis in sediment dwelling fish species, thus representing an important exposure pathway, and extending the bioavailability of sediment-sorbed pollutants to the food web. Accurate determinations of lipid content and lipid TEQDP contamination within seafood samples are critical to human exposure assessments. To ensure quality assurance, different seafood extraction methods were tested to evaluate their impact on lipid yields and contaminant concentration. While levels of PCDD/Fs and PCBs on a lipid basis did not vary across the different methods employed in this study, sample preparation is a significant determinant of lipid yield from fattier fish species. If samples were freeze dried prior to extraction, 30% higher TEQDP values (on a wet weight basis) were obtained as compared to extraction using fresh sample material. Such variance in lipid results will have a significant impact on exposure assessments and should be taken into consideration during seafood contaminant analysis. The median TEQDP concentration from local seafood was approximately 25 fold higher compared to the retail seafood analysed for the national Australian risk assessment. The seafood consumption survey results from this study further indicate that coastal subpopulations consume considerably more seafood than the general population (2 to 6 times more in the present case study). This proved to be an important driver for contaminant exposure in this subpopulation. The average monthly dioxin intake for the coastal community ranged between 34 (best case) to 107 (worst case) pg TEQ kg bw-1 month1, (95th percentile: 114 - 362 pg TEQ kg bw-1 month1), an order of magnitude higher than that estimated for the general population. The contaminant exposure via the local seafood consumption pathway alone exceeded WHO tolerable daily intake levels in 11-44% of the population. These results have important implications with respect to adequate contaminant exposure assessments of Australian and other coastal subpopulations. The study outcomes highlight the importance of considering local conditions and information on contaminant fate processes for human exposure evaluations. Local seafood consumption in coastal communities can result in high exposure to PCDD/F and PCBs, even in background contamination areas. This information would be important to consider for developing future sediment quality guidelines and with respect to exposure and associated risks for coastal communities in general.

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references. Also available in electronic format on the Internet.

Thesis (M.A.)--Catholic Theological Union at Chicago, 1996. / Vita. Includes bibliographical references (leaves 80-85).

Thesis (M. A.)--Trinity Evangelical Divinity School, Deerfield, Ill., 1997. / Abstract. Includes bibliographical references (leaves 108-114).

Thesis (M.A.)--Catholic Theological Union at Chicago, 1996. / Vita. Includes bibliographical references (leaves 80-85).

Thesis (M.A.)--Catholic Theological Union at Chicago, 1996. / Vita. Includes bibliographical references (leaves 80-85).

Due to environmental concerns, most of persistent organic pollutants (POPs) have been eliminated or reduced in production and use; however, due to their great persistency, POPs are expected still to be found in the environment long after their use has ceased. Although, in recent years, POPs have rarely been detected in river water in the United Kingdom (UK), their concentrations in fish (biota) and sediment are expected to be notable due to their lipophilicity and bioaccumulation; however, there is a lack of information and data to understand the current contamination of POPs in catchments and evaluate their potential risk to the environment and ecosystem. This thesis describes the application of mathematical modelling approaches to (i) predict the current distribution and concentration of POPs in catchments, (ii) evaluate the influence of climate change and extreme weather conditions on the fate of POPs, and (iii) provide guidelines to inform decision-making on managing the potential risks of POPs in river basins. The modelling studies have mainly focused on polychlorinated biphenyls (PCBs). The River Thames catchment was chosen as the study area. The Fugacity level III model was initially used to describe the general distribution of PCBs between different compartments; it was predicted that the greatest mass of PCBs remain in the soil, but the fish and sediments represent compartments with the highest PCB concentrations. The contamination of PCBs in Thames fish was estimated to exceed the unrestricted consumption thresholds of 5.9 μg/kg for ∑PCBs set by the U.S. Environmental Protection Agency (EPA); no current EU Environmental Quality Standards (EQS) are available for PCBs in fish. It was indicated that the PCBs in fish could be linked to PCB contamination in sediment, which was predicted to be about three times higher than the fish concentrations, but insufficient observed data of PCBs in Thames fish and sediment are available to validate the results. In order to address this limitation in observed data, fish and sediment sampling and chemical analysis were carried out for the presence of POPs. In addition to PCBs, the measured results for hexachlorobenzene (HCB) and polybrominated diphenyl ethers (PBDEs) in Thames fish and sediment were assessed. Although the observed fish- and sediment concentrations of the chemicals appear quite variable, when normalised to organic carbon the levels in sediment, they were comparable to the fish lipid normalised concentrations. Using the temperature and rainfall data forecasts in the UK Climate Projections 2009 (UKCP09), climate change scenarios were established and assessed in the fugacity modelling. The modelling results suggested a modest influence of climate change on PCB fate over the next 80 years. The most significant result was a tendency, in the Thames catchment, for climate change to enhance the evaporation of PCBs from soil to air. While the fugacity model successfully simulated the distribution and fate of PCBs, we used greatly simplified representations of climate, hydrology and biogeochemical processes of the catchment: to have a deeper understanding, a newly developed dynamic hydrobiogeochemical transport model - the Integrated Catchment Contaminants model (INCAContaminants) was applied. Using additional information about weather, river flows and water chemistry, the INCA-Contaminants model provided new insights into the behaviour of contaminants in the catchment; this led to a better representation of PCB contamination in sediment. In addition, INCA demonstrated the important impact of short-term weather variation on PCB movement through the environment. It was shown that PCBs contamination in Thames sediment was greatly disturbed by the severe flooding that occurred in early 2014. This thesis presents the application of the INCA model to assess - in addition to POPs - the behaviour of metaldehyde in the River Thames catchment. Metaldehyde is a type of pesticide used mainly to kill snails and slugs. Its application in agricultural areas within the catchment area has in recent years caused severe problems with drinking water supply. The INCA model has proved to be an effective tool for simulating the transport of metaldehyde in the catchment, predicting observed metaldehyde concentrations at multiple locations in the River Thames; this is the first time that a dynamic modelling approach has been used to predict the behaviour of metaldehyde in river basins. Modelling results showed that high concentrations of metaldehyde in the river system are a direct consequence of excessive application rates. In this thesis, a simple decision-support tool was derived from modelling results, based on variable application rates and application areas. This decision-support tool is now being used by Thames Water to help control peak concentrations of metaldehyde at key water supply locations.

学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-09-25 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2864号 ; 請求記号: 新制/工/1421 ; 整理番号: 25549 / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13393号 / 工博第2864号 / 新制||工||1421(附属図書館) / 25549 / UT51-2007-Q794 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 引原 隆士, 教授 小林 哲生, 准教授 中村 武恒 / 学位規則第4条第1項該当

p. 1-112 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-04-10T18:15:14Z No. of bitstreams: 1 Tese _ Maria Efigenia.pdf: 1177812 bytes, checksum: e7ab5f7bbee1bf8001e5519270ae0b07 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-13T20:13:39Z (GMT) No. of bitstreams: 1 Tese _ Maria Efigenia.pdf: 1177812 bytes, checksum: e7ab5f7bbee1bf8001e5519270ae0b07 (MD5) / Made available in DSpace on 2013-04-13T20:13:39Z (GMT). No. of bitstreams: 1 Tese _ Maria Efigenia.pdf: 1177812 bytes, checksum: e7ab5f7bbee1bf8001e5519270ae0b07 (MD5) Previous issue date: 2009 / Objetivo: avaliar o efeito da suplementação dietética com o antioxidante N-acetilcisteína (NAC), oferecido a crianças com diarréia persistente. Método: trata-se de um ensaio clínico, duplo-cego, randomizado, controlado com placebo no qual foram estudadas 55 crianças, de ambos os sexos, com idades entre 02 e 36 meses, atendidas em um hospital pediátrico com diagnóstico de diarréia persistente ( 14 dias de duração). Os pacientes foram distribuídos, randomicamente, em dois grupos que receberam como dieta padrão o iogurte natural integral e a suplementação dietética com 3g de N-ACC(28 crianças) ou placebo(27 crianças) duas vezes ao dia. Estas crianças foram mantidas em uma unidade metabólica, onde o peso, a ingestão dietética de soro de reidratação oral e água, assim como as perdas fecais, urinárias e por vômitos, foram mensuradas durante todo o estudo e analisadas a cada 24 horas. Foram realizadas avaliações antropométricas e bioquímicas no momento do internamento e da alta do estudo. Resultados: Ao final do período de observação, os dados mostraram que a mediana de duração da diarréia (h) e de perda fecal (ml/kg/dia) foram menores em favor do grupo teste, embora sem significância estatística. Conclusão: Este estudo demonstra que a utilização de NAC como suplemento na dieta de crianças com diarréia persistente pode proporcionar vantagem terapêutica em comparação com a alimentação convencional. / Salvador