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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Poluentes orgânicos persistentes na biota marinha do Arquipélago de São Pedro e São Paulo / Persistents Organic Pollutants in marine biota of the São Pedro e São Paulo Archipelago

Patrick Simões Dias 26 November 2010 (has links)
Algumas ilhas oceânicas como o Arquipélago de São Pedro e São Paulo podem ser consideradas áreas remotas e preservadas devido a sua distância do continente. Entretanto, essas regiões não estão isentas da influência de agentes antrópicos oriundos das regiões costeiras, como é o caso dos poluentes orgânicos persistentes (POPs). A presente proposta visou determinar a ocorrência e distribuição de POPs na biota marinha, do Arquipélago de São Pedro e São Paulo. As extrações das amostras foram realizadas em micro-ondas e os pesticidas organoclorados e os PCBs/PBDEs foram analisados respectivamente por cromatografia a gás com detecção por captura de elétrons e espectrometria de massas. Os compostos predominantes foram os PCBs e os DDTs que apresentaram, respectivamente, as concentrações máximas de: 127,7 e 34,37 ng g-1 para Exocoetus volitans (Peixe-voador), 98,15 e 8,89 ng g-1 para Sula leucogaster (Atobá-marrom) e 90,5 e 18,86 ng g-1 Grapsus grapsus (Aratu). Os baixos valores dos contaminantes sugerem um relativo grau de isolamento e preservação, porém a ocorrência e o perfil de distribuição dos PCBs sustenta a hipótese de que a principal fonte de contaminação em áreas remotas é o transporte atmosférico de longa distância, e demonstra a ubiquidade desses poluentes no ambiente marinho. / Some oceanic islands, such as São Pedro e São Paulo Archipelago may be considered remote areas and preserved due to its distance from the mainland. However, these areas are not exempt from the influence of anthropogenic agents from coastal regions, such as persistent organic pollutants (POPs). This proposal aimed to determine the occurrence and distribution of POPs in marine biota of São Pedro e São Paulo Archipelago. Samples extractions were performed with microwave and organochlorine pesticides and PCBs/PBDES was respectively analysed by gas chromatography with electron capture detection and mass spectrometry. The predominant compounds were PCBs and DDTs that presented, respectively, the maximum concentrations 127.7 and 34.37 ng g-1 to Exocoetus volitans (Flying fish), 98.15 and 8.89 ng g-1 to Sula leucogaster (Brown Booby) and 90.5 and 18.86 ng g-1 to Grapsus grapsus (Sally Lightfoot crab). The low levels of contaminants suggest a relative degree of isolation and preservation, but the occurrence and distribution profiles of PCBs supports the hypothesis that the main source of contamination in remote areas is long range atmospheric transport, and demonstrates the ubiquity of those pollutants in the marine environment.
82

Poluentes Orgânicos Persistentes (POPs) em toninhas (Pontoporia blainvillei; Cetacea, Pontoporiidae) acidentalmente capturadas em operações de pesca no litoral sul de São Paulo / Persistent Organic Pollutants (POPs) in franciscana (Pontoporia blainvillei; Cetacea, Pontoporiidae) accidentally caught in fishing operations in the south coast of São Paulo

Ana Paula Moreno Barbosa 06 May 2015 (has links)
Os poluentes orgânicos persistentes (POPs) são acumulados em tecidos gordurosos dos organismos vivos em concentrações relativamente altas em animais do topo da cadeia alimentar, como os golfinhos. Os objetivos deste trabalho foram avaliar a distribuição e acumulação de POPs em tecidos (gordura, fígado, rim e músculo) de toninhas (Pontoporia blainvillei) do litoral sul de São Paulo, bem como as diferenças/similaridades entre gênero e maturidade sexual e a transferência via placenta. Os valores de concentração mediana (ng g-1; peso úmido) para as 16 amostras de gordura, fígado, rim e músculo, respectivamente, foram: PCBs (987; 19,2; 5,08; 4,41); DDTs (550; 10,3; 2,67; 1,89); PBDEs (32,7; 0,230; 0,095; 0,050); Mirex (21,5; 0,457; 0,168; 0,083); HCB (15,4; <0,360; <0,360; <0,144); HCHs (<0,870; 2,20; <0,218; <0,087); Clordanas (<1,45; <0,362; <0,362; <0,145). Os machos jovens apresentaram as maiores concentrações dos POPs, seguidos pelos machos adultos, fêmeas jovens, fêmeas adultas e fetos. Foi observada transferência dos contaminantes das fêmeas gestantes para seus fetos entre 14 a 28% para PCBs e 19 a 45% para DDTs. A gordura apresentou correlação significativa com os demais tecidos estudados para acumulação dos PCBs, DDTs e PBDEs sugerindo a sua representatividade para estudos desses POPs em toninhas. / Persistent organic pollutants (POPs) are accumulated in fatty tissues of organisms in relatively high concentrations in animals in high position of the food chain such as dolphins. The aims of this study were to evaluate the distribution and accumulation of POPs in tissues (blubber, liver, kidney and muscle) of franciscana dolphin (Pontoporia blainvillei) collected on the southern coast of São Paulo as well as differences/similarities between genre and sexual maturity and the transplacental transfer. The values of median concentration (ng g-1; wet weight) for 16 samples of blubber, liver, kidney and muscle, respectively, were: PCBs (987; 19,2; 5,08; 4,41); DDTs (550; 10,3; 2,67; 1,89); PBDEs (32,7; 0,230; 0,095; 0,050); Mirex (21,5; 0,457; 0,168; 0,083); HCB (15,4; <0,360; <0,360; <0,144); HCHs (<0,870; 2,20; <0,218; <0,087); Chlordanes (<1,45; <0,362; <0,362; <0,145). POPs concentrations were higher in young males followed by adult males, young females, adult females and fetuses. Maternal transfer of POPs to the fetuses was between 14 to 28% for PCBs and 19 to 45% for DDTs. Blubber showed a significant correlation with the other tissues studied for PCBs, DDTs and PBDEs suggesting its representativeness for evaluation of these POPs in franciscana dolphin.
83

Avaliação da contaminação por hidrocarbonetos e organoclorados em diferentes compartimentos do ambiente marinho do Estado do Rio de Janeiro / Evaluation of the contamination of several compartiments of marine environment of the State of Rio de Janeiro by hidrocarbons and organochlorine

Satie Taniguchi 31 October 2001 (has links)
O ambiente marinho é o destino final de muitos contaminantes, como os PAHs, PCBs, DDTs e HCHs, que têm sido detectados em vários compartimentos do ambiente marinho, podendo trazer efeitos deletérios para o ecossistema. O objetivo deste trabalho foi a avaliação da contaminação por hidrocarbonetos alifáticos, PAHs, PCBs, DDTs e HCHs através da análise de 15 amostras de sedimento, 6 de mexilhão e 11 de fígado de peixe. Para isso, foi otimizada uma mesma metodologia para todas as matrizes bióticas. A amostragem foi feita ao longo da costa do estado do Rio de Janeiro, no período de 1996 a 1998, durante o Programa de Monitoramento do Ambiente do Meio Ambiente Marinho, promovido pela Marinha do Brasil. Os controles de qualidade analítica e confiabilidade dos dados gerados seguiram os padrões internacionais. A metodologia utilizada foi considerada satisfatória para análise dos organismos e sedimentos, de acordo com a avaliação feita através da análise de materiais de referência certificados. Os PCBs e DDTs apresentaram o fenômeno da magnificação com concentrações crescentes: sedimentos < mexilhões < peixes. Os HCHs apresentaram as maiores concentrações nos mexilhões. Os hidrocarbonetos alifáticos apresentaram concentrações similares nas três matrizes amostradas, o mesmo ocorrendo com os PAHs. As concentrações de hidrocarbonetos do petróleo indicam que as maiores introduções são próximas às áreas urbanas. Os PCBs e pesticidas também foram detectados em grande parte das amostras, mas em baixas concentrações. A fonte desses OCs para o ambiente marinho pode ser oriunda de outras regiões devido ao transporte e à deposição atmosférica. A comparação entre as matrizes mostrou a importância da análise simultânea de sedimentos e organismos em função da concentração de cada grupo de compostos e sua diferente acumulação. / The marine environment is the final recipient of many organic compounds that are widely found in seawater, sediments and organisms. The purpose of this study was the assessment of the contamination of aliphatic hydrocarbons, PAHs, PCBs, DDTs and HCHs through the analyses of 15 sediments, 6 mussels and 11 fish livers. The same methodology was optimized for biotic matrices. The sampling was performed from 1996 to 1998 along the Coast of the State of Rio de Janeiro, during the Brazilian Navy Environmental Monitoring Program. Quality assurance and quality control followed the international procedures. The methodology give satisfactory results in accord with the analyses of certified standard reference materials. Data of PCBs and DDTs from different matrices revealed increasing concentrations: sediment < mussel < fish. HCHs prevailed in mussels. Data of aliphatic hydrocarbons and PAHs were similar between sediments and organisms. Levels of petroleum hydrocarbons showed major inputs near the urban areas. PCBs and chlorinated pesticides were detected in the majority of samples but in low levels. These inputs can be attributed to long-range atmospheric transport. Comparison among the sampled matrices showed the importance of simultaneous analyses of sediments and organisms based in the concentration of each group of compounds and their different accumulations.
84

Application of polychlorinated biphenyl signatures for environmental fingerprinting

Megson, David Peter January 2014 (has links)
Polychlorinated Biphenyls (PCBs) are a group of 209 ‘man-made’ chlorinated organic compounds that were widely used in the 20th century for a variety of industrial uses. PCBs were first commercially produced in the 1929 and were manufactured until the 1980s when their use was phased out due to environmental and human health risks. However, due to their widespread use and persistence they are ubiquitous in the environment and remain a contaminant of concern. The structural properties that determine the persistence of PCBs in humans were therefore elucidated by statistical analysis of data from the National Health and Nutrition Examination Survey (NHANES). PCBs with chlorine bonding in the 2,5-and 2,3,6- positions (and 2- in di- and tri-chlorinated congeners) were rapidly biotransformed and so can be classed as episodic congeners whereas PCBs with chlorine bonding in the 2,3,4-, 2,4,5-, 3,4,5-, and 2,3,4,5- positions were more resistant to biotransformation and can therefore be classed as steady state congeners. A fundamental requirement of using PCB signatures for environmental fingerprinting is an effective analytical method capable of producing high resolution signatures from biological samples. An extraction and clean-up method was developed that was successfully applied to different biological matrices (blood and tissues). A two dimensional gas chromatography with time of flight mass spectrometry (GCxGC-ToFMS) method was designed and optimised to provide a congener specific method capable of identifying 200 out of the 209 PCBs, with detection limits in human serum in the range of 1 to 10 ng g-1 lipid. The extraction and detection methods were used to determine the source of PCB contamination and age date exposure in workers at a transformer dismantling plant. A total of 84 different PCB congeners were identified in the sera of 30 workers with concentrations of the 7 indicator PCBs ranging from 1.2 - 39 μg g-1 lipid. Analysis of PCB signatures was able to distinguish recent from prolonged exposure and also identified an additional source of inhalation exposure in a subgroup of workers. Analysis of 12 different tissue types obtained from the common guillemot (Uria aalge) suggested a high degree of perpetuation between the PCB signature in different tissue types. This shows that comparative assessments can be undertaken between animals using different tissue types and that small (1 g) samples of blood can be used as a non-lethal sampling technique. The regional provenance of 25 wrecked Leach’s storm petrels (Oceanodroma leucorhoa) was also determined using PCB signatures. Results from GCxGC-ToFMS analysis revealed distinctively different PCB signatures in birds from Canada and Europe. The findings reported in this thesis enhance our understanding of PCB signatures in the environment and show how they can be used effectively to age date and identify the source of exposure in humans and animals.
85

USE OF IN-SITU FISH POPULATIONS FOR BIOMONITORING POLYCHLORINATED BIPHENYL AND METAL POLLUTION IN MODERATELY IMPACTED FRESHWATER STREAMS

Price, David John 01 January 2007 (has links)
Water, sediments, floodplain soils, and fish from Big and Little Bayou creeks were assessed for polychlorinated biphenyls (PCBs) and metals in 1987-2005. The streams were impacted by effluents from the Paducah Gaseous Diffusion Plant (PGDP). PCBs were rarely detected in water samples. Aroclor 1248 detections in sediments and floodplains were sporadic, but 1254 and 1260 were consistent. Seasonal variations were only observed for Aroclor 1248. Detection of PCBs in floodplains indicated recent influx of contaminated sediments. Species-specific PCB residues patterns were studied for Lepomis cyanellus, L. megalotis, L. macrochirus, and Campostoma anomalum. Highest PCB concentrations were found in stoneroller minnows. PCBs decreased over time in sunfish species, but retained a baseline level. No relationships were found between sunfish age and PCB concentrations. At low PCB levels, green sunfish body burden (BB) did not correlate with lipid content. A certain PCB concentration must be exceeded before PCB BB correlates with lipid content. Stream flows differed by season, and fish PCB BB differed by season, but stream flow did not correlate with fish BB. Congener groups corresponded to Aroclor concentrations. Higher chlorinated biphenyls peaked in the spring for sport fish. PCBs remobilized in the spring resulted in higher summer BB for the stoneroller minnows, whereas sunfish eliminated PCBs by summer. This variability was due to the sunfishs ability to regulate PCBs. Metal concentrations did not display the seasonal variability evident in the PCB data. Water metals may have peaked during storm events and decreased rapidly. Water Pb increased with time, but the source could not determined. Zinc in Little Bayou creek likely originated from the PGDP. Except for Cu and Zn, stoneroller minnow metal BB decreased with time. Metal BB were used to determine bioavailable fractions. Less than half of the water column Cd, Cr, Fe, and Pb in impacted areas were bioavailable to stoneroller minnows, whereas 59% of Ag, 73% of Cu, and 64% of Zn were bioavailable. Cumulative criterion units were calculated to determine additive metal impacts, and proved useful in locating sectors with possible ecological impact. In-situ monitors proved valuable in studying PCB and metal behavior under real-world conditions.
86

Utilisation de matrices agro-alimentaires comme indicateurs de pollutions environnementales : exemple du lait

Bui, Xuan Thanh 19 December 2007 (has links) (PDF)
Le lait peut être utilisé comme indicateur de pollutions environementales car en général on est assuré de la bonne tracabilité de sa collecte. De nombreux solvants ont été utilisés pour séparer les principales phases du lait (protéines, lipides, sérum). Le mélange de solvants utilisés pour cette étude est le suivant: 1 vol de lait, 1 vol de solution NaCL à 0.9%, 2 vol d'éthanaol et 4 vol de dichlorométhane......
87

An evaluation of the distributions of polychlorinated biphenyls and organic matter in coastal sediments

Jönsson, Anders January 2004 (has links)
<p>The objective of this thesis is to improve the understanding of what processes and mechanism affects the distribution of polychlorinated biphenyls (PCBs) and organic carbon in coastal sediments. Because of the strong association of hydrophobic organic contaminants (HOCs) such as PCBs with organic matter in the aquatic environment, these two entities are naturally linked. The coastal environment is the most complex and dynamic part of the ocean when it comes to both cycling of organic matter and HOCs. This environment is characterised by the largest fluxes and most diverse sources of both entities. A wide array of methods was used to study these processes throughout this thesis. In the field sites in the Stockholm archipelago of the Baltic proper, bottom sediments and settling particulate matter were retrieved using sediment coring devices and sediment traps from morphometrically and seismically well-characterized locations. In the laboratory, the samples have been analysed for PCBs, stable carbon isotope ratios, carbon-nitrogen atom ratios as well as standard sediment properties. From the fieldwork in the Stockholm Archipelago and the following laboratory work it was concluded that the inner Stockholm archipelago has a low (≈ 4%) trapping efficiency for freshwater-derived organic carbon. The corollary is a large potential for long-range waterborne transport of OC and OC-associated nutrients and hydrophobic organic pollutants from urban Stockholm to more pristine offshore Baltic Sea ecosystems.</p><p>Theoretical work has been carried out using Geographical Information Systems (GIS) and statistical methods on a database of 4214 individual sediment samples, each with reported individual PCB congener concentrations. From this work it was concluded that the continental shelf sediments are key global inventories and ultimate sinks of PCBs. Depending on congener, 10-80% of the cumulative historical emissions to the environment are accounted for in continental shelf sediments. Further it was concluded that the many infamous and highly contaminated surface sediments of urban harbours and estuaries of contaminated rivers cannot be of importance as a secondary source to sustain the concentrations observed in remote sediments. Of the global shelf PCB inventory < 1% are in sediments near population centres while ≥ 90% is in remote areas (> 10 km from any dwellings). The remote sub-basin of the North Atlantic Ocean contains approximately half of the global shelf sediment inventory for most of the PCBs studied.</p>
88

Bacterial Challenge in Lumbricus Terrestris: A Terrestrial Invertebrate Immunotoxicity Model.

McDonald, Jennifer C. 05 1900 (has links)
A bacterial challenge assay was developed utilizing the earthworm, Lumbricus terrestris, in order to assess potential immunotoxic effects from exposure to specific polychlorinated biphenyl congeners. Earthworms were inoculated with Aeromonous hydrophila, establishing a 10-day LD50. In vitro assays for effects of PCBs on phagocytosis agreed with mammalian studies, demonstrating potent suppression of phagocytosis by the non-coplanar PCB congener 138 and no suppression by the coplanar congener 126. However, when the effects of the two PCB congeners were evaluated for suppression of resistance to a whole animal infection challenge assay, coplanar PCB 126 decreased the ability of L. terrestris to withstand infection while non-coplanar PCB 138 did not.
89

Pesticides et polyculture d'étang : de l'épandage sur le bassin versant aux résidus dans la chair de poisson / Pesticides and polyculture pond : from spreading on watershed to residues in fish flesh

Lazartigues, Angélique 15 November 2010 (has links)
Le devenir des pesticides en polyculture d’étang est peu étudié, en particulier la contamination de la chair des poissons proposés aux consommateurs. Cinq sites, correspondant chacun à un étang et à son bassin versant, ont été caractérisés. Ils s’échelonnent sur un gradient d’intensification agricole allant de 0% à 85% de la surface mise en culture. La somme des concentrations de pesticides quantifiés dans l’eau s’échelonne de 0,17 à 8,81 µg/L. La réponse biologique des poissons, évaluée par la recherche de huit biomarqueurs (EROD, CYP 3A, GST, CAT, SOD, GSH, GPx et AChE), a permis d’établir des différences entre les espèces et les sites étudiés. Une recherche ciblée de pesticides épandus sur grandes cultures, a été effectuée par une méthode multi-résidus, dans l’eau, les sédiments et la chair de poisson. L’isoproturon (valeur maximale 2,69µg/L) et le métazachlore (valeur maximale 0,54 µg/L) présentent les concentrations les plus élevées dans l’eau; la trifluraline (0,5 à 13 µg/kg PS) et l’isoproturon (0,7 à 56,4 µg/kg PS) dans les sédiments. Les profils de résidus dans la chair de poisson sont variables et seuls la trifluraline, l’isoproturon, le métazachlore et le carbendazime (valeurs maximales de 21 ; 0,75 ; 0,13 et 0,2 µg/kg PF, respectivement) sont quantifiés. Les facteurs de bioamplification et les demi-vies dans le muscle ont été évalués (10-6 < BMF < 10-3, 1j <DT50 < 40 j) pour la plupart des molécules. Au final, de nombreux facteurs, liés en particulier aux caractéristiques des sites (non maîtrisables) et aux pratiques de gestion (améliorables), influencent le profil des pesticides dans le muscle et la réponse biologique des poissons / Dam pond is connected to its watershed. Use of pesticides on watershed may lead to dissipation in the environment Transfer of registered pesticides remains poorly studied. Thus, the main objective of this work was to improve knowledge about the fate of pesticides in polyculture pond, especially contamination of fish flesh. Five sites, each site corresponding to a pond and its watershed, were characterized. They are placed on a gradient of crop proportion ranging from 0% to 85% of the watershed area. The sum of quantified molecules in water ranged from 0.17 to 8.81 µg / L. The biological response of fish, assessed by evaluation of eight biomarkers (EROD, CYP 3A, GST, CAT, SOD, GSH, GPx, and AChE), establish differences between species and sites studied. A study of 14 targeted pesticides was conducted by a multi-residues method in water, sediments and fish flesh. Isoproturon (maximum value 2.69 µg/L) and metazachlor (maximum value 0.54 µg/L) are the main contaminants in water; Trifluralin (0.5 to 13 µg/kg PS) and isoproturon (0.7 to 56.4 µg/kg PS) in sediments. Trifluralin, isoproturon, carbendazim and metazachlor (maximum values of 21, 0.75, 0.13 and 0.2 µg/kg PF, respectively) are quantified in muscle of fish. Low levels observed in fish can be explained by a low potential to bioaccumulate (measured ex-situ for some molecules, between 10-6 and 10-3). However, half-lives in the muscle may be several weeks depending, explaining the possibility to find molecules in fish flesh. Finally, many factors, particularly related to site characteristics (uncontrollable) and management practices (upgradable), influence profile of pesticides in muscle and biological responses of fish
90

Ocorrência de compostos organoclorados (pesticidas e PCBs) em mamíferos marinhos da costa de São Paulo (Brasil) e da Ilha Rei George (Antártica). / Occurrence of organochlorine compounds (pesticides and PCBs) in marine mammals from São Paulo coast (Brazil) and King George Island (Antarctica).

Yogui, Gilvan Takeshi 05 February 2002 (has links)
Os compostos organoclorados causam grande impacto na natureza devido a três características básicas: persistência ambiental, bioacumulação e alta toxicidade. Os mamíferos marinhos estão entre os organismos mais vulneráveis à toxicidade crônica desses contaminantes porque, além de concentrá-los em grande quantidade, a fêmea transfere parte de sua carga ao filhote durante a gestação e a lactação. Assim, o presente trabalho teve como objetivos otimizar uma metodologia para determinação de organoclorados (pesticidas e PCBs) em matrizes gordurosas e verificar a ocorrência dos mesmos na gordura subcutânea de mamíferos marinhos amostrados na costa de São Paulo (Brasil) e na Ilha Rei George (Antártica). No protocolo metodológico otimizado, a extração foi realizada em extrator Soxhlet (8 h) com uma mistura de n-hexano e diclorometano. A etapa de purificação foi feita através de tratamento ácido e o extrato final analisado em cromatógrafo a gás equipado com detector de captura de elétrons (GC-ECD). A performance do método foi avaliada com material de referência certificado, enquadrando-se dentro de padrões internacionais de controle de qualidade. O limite de detecção do método foi em média 2 ng g-1. As análises apontaram DDTs e PCBs como os grupos que mais causam impacto nos cetáceos da costa de São Paulo. Isso refletiu o histórico de ambos no Brasil, tanto em indústria como em agricultura e saúde pública. Em contrapartida, HCHs e HCB não apresentaram concentrações elevadas, fato que pode ser atribuído à volatilidade dos mesmos em regiões de clima tropical. Da mesma maneira, a-clordano, g-clordano e mirex não foram detectados em níveis significativos. A foca de Weddell (Leptonychotes weddelli), habitante do continente antártico, evidenciou as menores cargas de contaminante entre os animais estudados. As toninhas (Pontoporia blainvillei) e o golfinho-nariz-de-garrafa (Tursiops truncatus) também apresentaram baixos níveis de organoclorados. Os botos-cinza (Sotalia fluviatilis) revelaram concentrações de DDT iguais ou superiores a cetáceos da Índia, país onde esse pesticida ainda não está proibido. Já o golfinho-de-dentes-rugosos (Steno bredanensis) mostrou a maior contaminação entre os animais analisados, comparável a espécies estudadas em águas costeiras de países desenvolvidos (onde os organoclorados foram muito utilizados). / Organochlorine compounds cause strong impact on the nature, as a consequence of three basic characteristics: environmental persistence, bioaccumulation, and high toxicity. The marine mammals are one of the most vulnerable organisms to the chronic toxicity of these contaminants. Besides the high concentration in the body, the female transfers part of her load to the offspring during gestation and lactation. The aim of this study was (1) the optimization of a methodology for determining chlorinated hydrocarbons (pesticides and PCBs) in fatty biological matrices and (2) the analysis of organochlorines in marine mammals blubber sampled along São Paulo coast (Brazil) and King George Island (Antarctica). According to the optimized methodology, the extraction was carried out in Soxhlet apparatus (8 h) with a mixture of n-hexane and dichloromethane. The clean-up was carried out with acid treatment and the resulting extract injected into gas chromatography coupled to electron capture detector (GC-ECD). The method performance was evaluated with certified reference material and fitted for international standards of control quality. The mean method detection limit was 2 ng g-1. DDTs and PCBs were the most concentrated organochlorines in the cetaceans from São Paulo coast. These findings reflected their past usage in Brazil by industry, agriculture, and public health. On the other hand, both HCHs and HCB were not found in high concentration likely due to their volatility in tropical climate areas. Mirex, a-chlordane and g-chlordane were not detected in elevated levels. The Weddell seal (Leptonychotes weddelli), from Antarctic continent, presented the smallest load among the studied animals. As the same way, the franciscanas (Pontoporia blainvillei) and the bottlenose dolphin (Tursiops truncatus) presented low organochlorine levels. The marine tucuxi (Sotalia fluviatilis) showed equal or higher DDT concentration than Indian cetaceans where that pesticide is still in use. The rough-toothed dolphin (Steno bredanensis) revealed the greatest contamination among the analyzed animals, comparable to species studied in the coastal waters of developed countries (where organochlorines were extensively used).

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