TY - THES TI - Green Roof, Nature-based Solutions, Biodiversity, Sustainability, Macao SAR, China AU - Lei, Man Sao A3 - Gonçalves, David A3 - Calheiros, Cristina AB - According to the United Nations (UN) World Urbanization Prospects 2018, cities are growing in both size and number, posing challenges for sustainable development. With urbanization, the increase of impermeabilization and landscape fragmentation urges for territorial planning and resources management. To promote resilient and resourceful cites, strategic planning where nature-based solutions (NBS) are included into the built environment, counteracting the negative effects of urbanization through the provision of ecosystem services, should be considered. Green roofs (GR) are an example of NBS that provide a panoply of ecosystem services at the level of the building and city, besides contributing for climate change mitigation and adaptation. This NBS can be included in the urban planning agenda in the new building or as a retrofit solution in the existing built environment. Macao SAR (here mentioned as Macao) is the second more densely populated city in the world, according to the UN Department of Economic and Social Affairs Population Division. The present study aims to assess the inclusion of GR in Macao and assess the ecosystem services that they may provide in a holistic approach aligned with the city’s sustainable development. For this purpose, an extensive GR implemented in Taipa Island of Macao was monitored in terms of associated biodiversity and carbon cycle assessment. Further on, it was carried out a comparison between this GR and a conventional roof (CR) in terms of surface thermal buffering. The results of this study have shown to be very promising in terms of the applicability of GR in Macao and on the relevant ecosystem services that they can provide. First, data loggers were installed in the GR and CR to assess the impact on temperature mitigation. The GR had a significant effect in decreasing and buffering temperature at the surface, with temperatures of 35.6 ºC in the GR substrate comparing with temperatures of 57.7 ºC in the CR surface. The results show that GR can be a cost-efficiency strategy to reduce heating of buildings and their associated environmental and economic costs with cooling. Second, the biodiversity of plants and animals was assessed using a combination of methods. It was observed a high level of biodiversity under a low maintenance and low disturbance of GR vegetation, with 23 species of plants and 34 species of animals identified. This shows that GR can contribute to increase biodiversity in cities. Third, an experiment was run with leaf litter bags to investigate the role of macrofauna (e.g., insects) in the decomposition of organic matter. With macrofauna activity, the decomposition rate increased 17 % when compared to decomposition rates without macrofauna, suggesting that the animals harboured in GR, in particular insects, play a key role in organic matter decomposition and thus on the carbon cycle in cities. This work is, to our knowledge, the first empirical GR study in Macao. The results support the application of GR in Macao for temperature mitigation, biodiversity increase and carbon sequestration, promoting the integration of this NBS in the future urban planning and policy of the city. More generally, the work supports the use of GR as an important NBS to mitigate the impact of climate change in urban settings CN - D-SC 2023 LEI,MAN CY - Macau DA - 2023/// PY - 2023 DP - Library Catalog (Koha) SP - 142 PB - University of Saint Joseph UR - https://library-opac.usj.edu.mo/cgi-bin/koha/opac-detail.pl?biblionumber=216031 KW - Biodiversity KW - China KW - Green Roof KW - Macao SAR KW - Nature-based Solutions KW - Sustainability ER - TY - THES TI - ISOLATION AND CHARACTERISATION OF PLASTIC POLYETHYLENE TEREPHTHALATE (PET) DEGRADING AND POLYHYDROXYALKANOATES (PHAs) PRODUCING BACTERIA FROM SOIL AND WATER AU - Saidu, Muhammad Bashir A3 - Gonçalves, David A3 - Castro, Paula M. L. A3 - Moreira, Irina Sousa A3 - University of Saint Joseph AB - The demand for plastic has led to enormous plastic waste in the environment, which persist and negatively impact the ecosystems. Polyethylene terephthalate (PET) is one of the most common thermoplastic polymers available on the market. The concerns about plastic waste generated an interest in strategies to enhance its biodegradation and finding alternative polymers. In this work was investigated the possibility of using bacteria to degrade PET and to produce bioplastics (Polyhydroxyalkanoates, PHAs). Finally, the integration of the two processes was tested. Overall, the work aimed to investigate the potential to recycle PET into bioplastic using bacteria. The potential of bacterial consortia from various environmental samples to degrade PET granules in liquid matrix was investigated. . The results revealed maximum PET granules degradation of 1.1 % by one of the tested consortia. PET degradation intermediate terephthalic acid (TPA) was not detected at the end of 55 days. Fourier-transform infrared spectroscopy (FTIR) results showed major spectral peak shifts and bends on PET chemical structure compared to non-inoculated control. The biodegradation of PET films buried in the soil (A), with mangrove plants (B), and bioaugmented with a bacterial consortium (C) was also investigated. The experiments were conducted for 270 days at ambient conditions. The results revealed no difference between treatments in the degradation, with a maximum weight loss of 0.118 % in the bioaugmented treatment. Nevertheless, Scanning Electron Microscope (SEM) and FTIR results indicated significant surface changes, spectral peak shifts, and stretches in PET chemical structures. Bacterial consortia isolated from the soil of the experimental treatments were assessed for degradation of PET monomers, TPA and monoethylene glycol (MEG), and intermediate Bis(2-hydroxyethyl) terephthalate (BHET). The consortia were inoculated in flasks containing minimal media with 1000 mg/L TPA or BHET or1113 mg/L MEG as the sole carbon source. Results showed complete degradation of TPA and significant degradation of BHET (96.09%), and MEG (83.65%) by the consortia. In the second part of the study, bacteria were isolated from various environmental samples and screened for PHA production using Sudan Black B staining on colonies and smeared glass slides. Transmission Electron Microscope images were captured to confirm the intracellular PHA inclusions. A total of 35 isolates were screened for PHA, and 22 showed positive staining. The isolate showing higher levels of PHA synthesis (EC2-30-3) was identified based on 16S rRNA gene sequence as Bacillus sp. and selected for PET monomers degradation and fermentation cultures for PHA production. It was cultured in minimal (Moreira et al., 2013) media with 1000 mg/L TPA and 1113 mg/L MEG as the carbon source for eight days. The isolate grew better in media containing MEG, which was selected as a substrate model for PHA fermentation. To integrate PET monomers biodegradation and production of PHA, the isolate was cultured in 0.2 % MEG. A control with 0.2 % of glucose was prepared, and the cultures were incubated for 96 hours. Bacillus sp. EC2-30-3 showed higher PHA accumulation in media supplied with MEG (40.31%) than glucose (25.53%). This is the first report showing that Bacillus sp. uses PET monomer as carbon source to produce a biopolymer. FTIR results of the extracted PHA identified its functional units as C–H, CH3, C=O, and C–O groups. The absorption bands obtained are closely related to the structure of PHB. The study thus confirmed the ability of the isolated bacteria to degrade PET monomers and produce biopolymers. The results of this work open the possibility for upscaling the use of bacteria to mitigate the impact of PET on the environment while producing environmentally friendly bioplastics CN - D-SC 2023 SAI,MUH CY - Macau DA - 2023/// PY - 2023 DP - Library Catalog (Koha) SP - 134 PB - University of Saint Joseph UR - https://library-opac.usj.edu.mo/cgi-bin/koha/opac-detail.pl?biblionumber=220134 KW - Biodiversity KW - China KW - Green Roof KW - Macao SAR KW - Nature-based Solutions KW - Sustainability KW - Thesis and Dissertations PhD in Science (D-SC) KW - University of Saint Joseph ER - TY - THES TI - SURVIVAL, MORPHOLOGY AND REPRODUCTION OF ENHALUS ACOROIDES (L.f.) ROYLE IN THE BOLINAO-ANDA REEF SYSTEM, NW PHILIPPINES: EFFECTS OF VARYING LIGHT CONDITIONS AU - Tagulao, Karen Araño A3 - Chan Shek Kiu A3 - Rollon, Rene A3 - University of Saint Joseph AB - Seagrasses play a critical role in coastal ecosystems worldwide, providing various ecosystem services based on their region and genus. In Southeast Asia, where seagrass biodiversity and extents are at their highest, the livelihoods and food security of many coastal communities depend on these plants. Despite their ecological and economic importance, seagrasses face global threats from human activities such as pollution and land use changes. Enhalus acoroides, a widely distributed seagrass species in the tropical Indo-Pacific region, is particularly valuable for coastal management and conservation efforts due to its size and provision of various ecosystem services. Although previous research has indicated that it is less sensitive to environmental changes than other tropical seagrass species, recent reports highlight its vulnerability to siltation and eutrophication. This dissertation aimed to examine how Enhalus responds and adapts to changes in light availability, taking into account both morphological adaptation and phenotypic plasticity. Field surveys, reciprocal transplantation field experiments, and investigations of sexual reproductive effort were conducted in the Bolinao-Anda Reef system (NW Philippines) to evaluate the impact of long-term environmental changes on Enhalus populations. The findings of this study revealed that Enhalus has the capacity to adapt its traits and survive changes in depth, light gradients, and different habitat types. This is evidenced by larger shoots in low-light environments, which is apparently a response to the reduction in light availability, as evidenced in both in situ and experimental setups. Larger leaf surface area in light-reduced setups also had higher concentration of chlorophylls a and b pigments. Transplants from light-reduced environments, although morphologically large, appeared more vulnerable (with low survival values) to environmental changes associated with translocation. Being morphologically large is therefore likely a stress response to light reduction, allocating more energy on light harvesting than sexual reproduction. Reciprocal transplantation experiments indicated a high survival rate, suggesting the potential of Enhalus for use in rehabilitation. However, despite having wider plasticity to adapt to light-limitation, they can be wiped out when threshold is reached. This thesis underscores the need for further research on Enhalus' response to stressors, genetic variation, and adaptive capacity to address conservation and management challenges CN - M-SC 2023 TAG,KAR CY - Macau DA - 2023/// PY - 2023 DP - Library Catalog (Koha) SP - 171 PB - University of Saint Joseph ST - SURVIVAL, MORPHOLOGY AND REPRODUCTION OF ENHALUS ACOROIDES (L.f.) ROYLE IN THE BOLINAO-ANDA REEF SYSTEM, NW PHILIPPINES UR - https://library-opac.usj.edu.mo/cgi-bin/koha/opac-detail.pl?biblionumber=216034 KW - Enhalus acoroides KW - Thesis and Dissertations PhD in Science (D-SC) KW - University of Saint Joseph KW - light availability KW - phenotypic plasticity KW - seagrass KW - transplantation ER - TY - THES TI - Neuronal Mechanisms of Behavioural Plasticity in the Peacock Blenny Salaria Pavo AU - Vieira, Pedro Cachapa A3 - Gonçalves, David AB - "Adult neurogenesis, i.e., the production of new neurons in the adult brain, has been studied intensively in the past years, both in humans and in animal models, as the understanding of this process can have major clinical implications. The study of neurogenesis in fish has been receiving more attention as, unlike mammals, they possess remarkably high levels of adult neurogenesis and a high capability for neuronal regeneration and replacement where neuronal death has occurred. Less is known, however, on the importance of adult neurogenesis for behavioural plasticity, i.e., for the capacity to change behaviour according to context. As a product of the brain, behaviour relies on functional neuronal networks and it may be expected that more permanent changes in behavioural states imply structural reorganization of neuronal circuits, with the integration of new neurons. Interestingly, the high level of brain plasticity of fish is paralleled by a high degree of behavioural plasticity, with many examples of species that change, either reversibly or irreversibly, their behavioural phenotype during their lifetime, as illustrated by species with functional sex-change and alternative reproductive phenotypes. Flexibility in behaviour may thus require a reorganization of neuronal networks underlying these behaviours with recruitment of new neurons. In this thesis, the link between brain and behavioural plasticity was studied in a small marine fish that inhabits the Mediterranean and adjacent Atlantic coasts, the peacock blenny Salaria pavo. In this species, males adopt nests in rock crevices and attract females into the nest for egg laying, with the male taking care of the eggs until hatching. In some populations, a scarcity of nest sites drives smaller and young males to adopt an alternative reproductive tactic to reproduce. These “sneaker” males mimic the females’ morphology and reproductive behaviour in order to illude the larger nesting males and parasitically fertilize eggs during mating events. Sneaker males later transition into the nesting male phenotype, and this major behavioural transformation in the same animal, first courting males and afterwards courting females, may imply significant reorganization of brain areas associated with reproductive behaviour. During the study, a brain atlas for the species was developed and the main cell proliferation regions, i.e. niches of stem cells birth that may differentiate into cells of the nervous system, characterized. Proliferative areas were observed throughout the whole brain and paralleled the pattern described for other teleosts. Proliferative cells were abundant namely in areas like the olfactory bulbs (granular and glomerular), the anterior subdivision of the dorsomedial telencephalon (DMa), the dorsal and ventral part of the ventral subdivision of the dorsomedial telencephalon (DMvd and DMvv), the dorsal part of the dorsal subdivision of the dorsomedial telencephalon (DMdd), the posterior subdivision of the dorsolateral telencephalon (DLp), the posterior zone of the dorsal telencephalic area (DP), the preoptic area (POA), the dorsal, supracommissural and ventral nucleus of the ventral telencephalic area (Vd, Vs and Vv), the optic tectum and its periventricular grey zone (TeO and PGZ), the ventral zone of the periventricular hypothalamus (Hv), the cerebellum, mainly the molecular layer (CCeM) and the caudal lobe (LCa). A study of the brain nuclei activated during female courtship events using immediate early-genes suggested that some of the areas of the social behaviour network (SBN), a set of brain nuclei underlying the expression of social behaviour across vertebrates, are implicated in female courtship, in particular nuclei in the ventral telencephalic regions. This was followed by an experiment to investigate the possible link between cell proliferation and male tactic switch. Nest availability was manipulated to allow a fraction of sneaker males to adopt a nest and start the transition to nesting males. Ten days after the experiment, some of the smaller males had indeed started switching into nesting males, adopting a nest and starting to develop male secondary sexual characters. The pattern of brain proliferation was studied in these fish to try to confirm that the irreversible behavioural transition would be associated with the reorganization of brain nuclei, assuming that cell proliferation relates to neurogenesis and structural reorganization. Transitional males had elevated cell proliferation levels, as compared to males that remained sneakers, in the dorsolateral anterior and posterior telencephalic regions, thought to be homologous to the hippocampus in mammals. Cell proliferation levels were generally elevated in ventral and ventromedial telencephalic nuclei in both sneakers and transitional males, as compared with nesting males and females, areas considered to be homologous to nuclei of the amygdaloid complex of mammals. There was large variation in proliferation levels within transitional males, and in particular one male more advanced in the transition had higher numbers of BrdU-positive cells than the others. This suggests that a longer time-window for detecting the peak in brain cell proliferation associated with tactic transition in some fish may have been needed. Overall, the study supports the hypothesis that behavioural transition in males of this species is paralleled by an increase in cell proliferation in nuclei potentially relevant for the expression of reproductive behaviours, and establishes the peacock blenny as a new relevant model for the study of neuronal plasticity in vertebrates." CN - D-SC 2023 VIE,PED CY - Macau DA - 2023/// PY - 2023 DP - Library Catalog (Koha) SP - 144 LA - eng PB - University of Saint Joseph UR - https://library-opac.usj.edu.mo/cgi-bin/koha/opac-detail.pl?biblionumber=207866 KW - Behavioural Plasticity KW - Neurogenesis KW - Peacock Blenny KW - Phenotypic Plasticity KW - Teleost Fish KW - Thesis and Dissertations PhD in Science (D-SC) KW - University of Saint Joseph ER - TY - THES TI - COP21 COMPLIANCE AND SUSTAINABLE DEVELOPMENT THROUGH INTEGRATED SOLID WASTE MANAGEMENT: IMPLEMENTATION PERSPECTIVES OF THE CIRCULAR ECONOMY IN THE PEARL RIVER DELTA AREA AU - Li, Warren Man Ho A3 - Gassner, Franz AB - The global living standard improved significantly in the last decades and China moved 800 million people out of poverty since 1980. However, production and consumption in their current forms are unsustainable in matters of resource and energy use and involved emissions with their significant ecological impact. The global human community committed itself in the COP21 Agreement of Paris 2015 to reduce Green House Gas (GHG) emissions based on National Determined Contributions (NDCs) in order to limit the increase of global average temperature below 2°C or better 1.5°C above pre industrial levels. This commitment entails a comprehensive transformation of the current social and economic system in view of decoupling economic growth from both resource extraction and GHG emissions, in view of fostering a resource sensitive and CO2 neutral Circular Economy (CE) based on Sustainable Development (SD). China submitted its first Intended Nationally Determined Contributions (INDCs) in 2015 with policies and measures affecting 15 major areas. In 2020, President Xi Jinping announced the commitment to peak China’s carbon dioxide emissions before 2030 and achieving carbon neutrality before 2060. Proper and Integrated Resource and Waste Management is central on the way to achieve the transformation into a CE. The State Council of the People’s Republic of China (PRC) released its plan “生活垃圾分类制度实施方案” to promote source separation of household waste on March 30, 2017 aiming at the recycling rate for household waste to reach 35% by 2020 for the selected cities. The first China’s Mandatory Waste Source Separation Law “廣州 市生活垃圾分類管理條例” was enforced by the city of Guangzhou on July 1st, 2018. One of the key strategic plans in China is the development of the Greater Bay Area (GBA) with its comprehensive development plan released on February 18, 2019. Following the INDCs by China, parts of the GBA Development Plan emphasize that the development of the CE systems and the implementation of extended producer responsibility (EPR), are effective principles to provide financial incentives in view of reducing embedded emissions in material and processes. The present research studied, analysed, and compared the MSW treatment strategies, rules, regulations, and retrievable data, which lead to MSW source separation and the reverse logistic of separated waste among 4 selected cities Guangzhou, Zhuhai, and the 2 S.A.R.s of Hong Kong and Macao. The experience and comparison from Guangzhou and Hong Kong revealed that a Top-down approach in environmental policy decision making is more efficient and is able to implement necessary policies faster. However, the experiences from Guangzhou and Zhuhai indicate, that also a more participatory implementation process is crucial, as it enables the involved stakeholders to express their experiences and opinions properly, which can lead to a higher level of policy feasibility and acceptance and a smoother operation accompanied with a higher effectiveness. For the two SARs, to achieve the objective to increase the recycling rate, the local Government must seek approval from China’s Central Government to allow locally generated recyclable material, in their original form, to enter mainland China for further treatment and to be turned into secondary raw material. Without such a proper support by a reverse resource logistic from the mainland, the CE schemes, such as the Mandatory Waste Source Separation, Producer Responsibility Scheme (PRS), Waste Charging Scheme, are not able to be implemented effectively. The current approach of the Local Government purchasing of recycling and exportation services of recyclable materials from private companies, and the sole reliance on existing market forces to handle, process, and export recyclable material out of the S.A.R.s cannot ensure a reliable and continuous operation in view of mitigating involved emissions. By way of a comparative analyses, the present investigation works out and distils suggestions for best practices of implementing the CE to comply with targets of emission reductions CN - D-SC 2022 LI,WAR CY - Macau DA - 2022/// PY - 2022 DP - Library Catalog (Koha) SP - 257 LA - eng PB - University of Saint Joseph ST - COP21 COMPLIANCE AND SUSTAINABLE DEVELOPMENT THROUGH INTEGRATED SOLID WASTE MANAGEMENT UR - https://library-opac.usj.edu.mo/cgi-bin/koha/opac-detail.pl?biblionumber=204548 KW - Circular Economy (CE) KW - Sustainable Development Goals (SDGs) KW - Thesis and Dissertations PhD in Science (D-SC) KW - University of Saint Joseph KW - Waste Hierarchy KW - Zeroand- Low-Waste-Systems ER - TY - THES TI - Behavioural and endocrine impact of artificial selection for winning in the siamese fighting fish AU - Ramos, Andreia Maria Cerejo AU - Gonçalves, David A3 - University of Saint Joseph AB - Aggression clearly has an adaptive value as it is necessary to secure resources for survival, growth, and reproduction. The Siamese fighting fish, Betta splendens, have endured a prolonged process of artificial selection for winning paired-fight contests across Southeast Asia, resulting in strains of short-fin aggressive “fighters”. Across centuries, Thai breeders have been selecting these strains by discarding loser batches and allowing winner batches to breed, claiming that they are significantly more aggressive than wild-types. This natural experiment provides a powerful context to investigate the biological basis of aggressive behaviour in fish, the topic of this thesis. To study aggression, it is important to validate and standardize behavioural assays appropriate for the species under study. Further, different aggression-eliciting stimuli, such as live opponents, 3D models, video playback, or mirror images, may elicit non-equivalent behavioural and physiological responses. For B. splendens, in particular, quantifying aggression from live fights is not ethically acceptable as the high levels of aggression of this species usually result in injuries or even death of the opponent. In Chapter II, it was shown that mirror images elicit very similar aggressive displays and endocrine responses to an interacting opponent behind a transparent partition, validating the use of this test to measure aggression in this model species. Further, it was shown that circulating levels of both androgens (11-ketotestosterone and testosterone) and corticosteroids (cortisol) increased in response to the aggression challenge, even in the absence of conflict resolution, questioning the role of these hormones during present and future aggressive contests. Using the previously validated mirror assay and also tests with live conspecifics, we assessed the impact of selection for winning by comparing, in Chapter III, male and female aggressive behaviour of lab-raised fighter and wild-type strains. The hypothesis that selection for male winners enhanced aggressive displays was confirmed, suggesting that the duration and frequency of threat and attack behaviour correlates with winning probability. However, females of the fighter strain, which are not selected for fights, were also more aggressive than wild-type females. This suggests that male and female aggression share common genetic pathways and physiological mechanisms and raises the possibility that selection for alleles that favour male aggression may have promoted intersexual genetic conflict in this species. After confirming the expected differences in aggressive behaviour between fighter and wild-type fish, the following question was whether endocrine systems, in particular those previously shown to respond to aggression, could have been targeted by the selection process. From previous studies in fish and other vertebrates, it was hypothesised that selection for winners could have increased constitutive levels of androgens or led to an enhanced androgen response to a social challenge. However, in chapter IV, it was shown that levels of 11-ketotestosterone and its response to aggression was similar in males of both strains, questioning the role of androgens in the modulation of aggression in B. splendens. On the contrary, constitutive levels of cortisol and the response of this hormone to an aggression challenge were higher in wild-type compared with fighter fish, supporting previous findings that associated high aggression with a blunted cortisol response. Overall, results from Chapter IV suggest that selection for winning had a stronger impact on the hypothalamus-pituitary-interrenal axis than in the hypothalamus-pituitary-gonadal axis. My results support the assumption of the “Challenge Hypothesis” proposed by John Wingfield and collaborators in 1990 to explain the relationship between androgens and aggression, according to which androgen levels above a reproductive baseline are a consequence of the frequency and intensity of social interactions, in particular of male-male agonistic encounters. It is becoming clear that androgens increase rapidly after an aggressive contest, independently of fight outcome. However, the function of this increase remains unclear as the frequency of aggressive displays was unrelated with post-fight androgen levels and constitutive levels of androgens, and androgen responsiveness, were similar between fighter and wild-type males. Results obtained for cortisol agree with a “corticosteroid-mediated dominance hypothesis” whereby low baseline levels and a blunted response of corticosteroids would be associated with a dominant status and high aggression. The work advances our knowledge about the endocrine regulation of aggressive behaviour in B. splendens and opens several testable hypotheses about the role of androgens and corticosteroids in the regulation of fish aggressive behaviour CN - D-SC 2021 RAM,AND CY - Macau DA - 2021/// PY - 2021 DP - Library Catalog (Koha) SP - 167 LA - eng PB - University of Saint Joseph KW - Thesis and Dissertations PhD in Science (D-SC) KW - University of Saint Joseph ER - TY - THES TI - The Roles of the Mangroves on the Bioaccumulation and Citogenotoxic Effects of Heavy Metals and Pesticides in the Food Web of a Tropical System AU - Gonzalez, Lucia Ivorra A3 - Chen, Shek Kiu A3 - Cardoso, Patrícia Gonçalves Marques AB - Mangroves are a unique group of plants, which offer a great variety of goods and services to the ecosystem and to the society. Regrettably, they have been globally threatened by urbanization and industrialization, among others, triggering overexploitation of the world’s mangrove forests despite their ecological and economic importance. As a result, mangroves are often under pollution stress as sinks or receivers for numerous man-made pollutants such as pesticides, which are the main focus of this thesis. One of the most widely applied chemicals in the word are the organochlorine pesticides (OCPs) that even after their supposedly worldwide ban between 1950s-1990s, they can still be detected in the environment. Numerous studies have been done in phytoremediation of pollutants by mangroves, but little attention has been given to the role of mangroves in the remediation of OCPs. For this reason, part of this thesis will focus on the occurrence and distribution of OCPs in intertidal tropical and sub-tropical areas around the world with and without mangroves. As a first goal (I), we evaluate —in a theoretical way— if the presence of mangroves affects or modifies the levels of OCPs in the surrounding environment. For this purpose, data from different matrices, such as water, sediment, benthic fauna and plants were included and discussed in this work. Moreover, and considering Macao’s location, we also quantified OCPs from surface waters of this region from areas with and without mangroves and included in this task. Besides this theoretical approach, this thesis also included some laboratoy and field work specifically focused on dicofol and 4,4’-dichlorobenzophenone (4,4’-DCBP, its main metabolite). Dicofol is an OCP strongly related to dichlorodiphenyltrichloroethane (DDT), which has been extensively used in China and more specifically, in the Pearl River Delta (PRD), a region under anthropogenic pressure. However, due to dicofol’s instability (i.e., sensitive to low pH, light exposure and high temperature), we expected to quantify 4,4′-DCBP (which is also common to DDT) as the main form present in the environment. As a second goal (II), we conducted a monitoring study in surface waters from Macao and Hong Kong, to evaluate the contamination status and water quality of these regions. Concentrations of 4,4’-DCBP, nutrients and physicochemical parameters were measured during transition and wet season, and at high and low tide. In addition, since the toxicity of this metabolite was totally unknown, we assessed it via two biological models: Daphnia magna and Artemia salina. Since 4,4’-DCBP was detected and quantified in both regions (2.8-30.0 ng/L), this thesis also includes experimental work focused on the assimilation and depuration pattern by a marine organism. For that purpose and as a final goal (III), we selected the common edible bivalve Meretrix as a model to evaluate the dynamics of accumulation and depuration of the pesticide dicofol. The Vietnamese clams were exposed during 15 days under two different concentrations of dicofol, and decontaminated for the same period of time. Quantification of 4,4’-DCBP was done during both phases (uptake and depuration) and at different sampling times. In summary, all these different works helped us to conclude that: I.1) As expected, vegetated areas with mangroves presented lower concentrations of OCPs for all the matrices, and also better quality in terms of pesticide pollution for water and sediments. Results obtained from Macao’s waters also revealed the same pattern, with mangroves areas having lower levels of contamination. Although the gathered data presented methodological variability (i.e. different quantification methods, extraction protocols, equipment used), the same pattern was observed among matrices, showing how robust and solid the results herein obtained are. II.1). Hong Kong presented higher concentrations of 4,4’-DCBP than Macao, which may be due to the use of dicofol as a pesticide and the use of antifouling-paint for ships. Moreover, concentrations of 4,4’-DCBP during wet season were below limits of quantification, demonstrating a seasonal pattern and a dilution effect due to higher river discharges during this period. II.2). Both regions showed possible eutrophication problems due to the high nutrient concentrations. These levels presented also a seasonal variability, with dissolved inorganic nitrogen and total dissolved solids higher during transition; and dissolved inorganic phosphorous, total suspended solids and chlorophyll a higher during wet season. II.3). Toxicity of 4,4’-DCBP was lower than the parent compound dicofol, and the levels quantified indicated a low environmental risk. However, it is important to pay attention to this compound since interaction with other contaminants could enhance their toxicity, or processes such as biomagnification or bioaccumulation could make low concentrations a threat for the environment. III.1). Different concentrations of dicofol presented different uptake and depuration kinetics. Animals exposed to higher concentrations (500 ng/L), had levels above limits of quantification (LOQ) after 24h exposure, unlike the ones exposed to lower concentrations (50 ng/L), which had levels