Forests provide a multitude of ecological services and are one of Canada’s most important natural resources that support a profitable industry, especially in New Brunswick. The activities associated with harvesting and forest management have documented ecological impacts such as the increased mobilization of mercury from the land to adjacent streams. Methylated mercury bioaccumulates and biomagnifies (concentrates) through food webs and in headwater streams forestry has been shown to change its accumulation. However, not much is known about the spatial trends of mercury accumulation and biomagnification through stream food webs and how different forest management practices affect these trends. To delineate these patterns, food webs were sampled across a spatial gradient from three basins experiencing different levels of forest management intensity. At a basin scale, methylmercury concentrations were greatest in filtered water, food sources, and one invertebrate taxa in a harvested but less intensively managed basin, likely due to increased inorganic sediments and dissolved organic carbon also observed. Biomagnification was lower in this same basin, possibly from inefficient trophic transfer of methylmercury from food sources. Longitudinally this basin also showed differences in fine particulate organic matter (FPOM) and coarse particulate organic matter (CPOM) mercury compared to the other basins, likely due to similar spatial patterns in organic matter. In conclusion, mercury dynamics in stream food webs were impacted by forestry primarily in water and basal food sources at a basin scale, but spatial patterns were inconsistent. / Thesis / Master of Biological Science (MBioSci) / Forest harvesting is an essential and large part of Canada’s economy, and it is important to ensure that its impacts on freshwater systems are minimal. Forest management can increase the amount of the toxic metal mercury entering streams and this can have harmful effects in top predators, like fish, since mercury concentrates through food webs. The knowledge lacking is how different harvesting practices change the amount of mercury in these food webs and whether impacts increase as streams get larger. Of the three basins I studied, the one with harvesting but little assisted regeneration (moderately impacted) had the highest mercury levels in water, leaves, and algae. From upstream to downstream the leaves and biofilm from the moderately impacted basin accumulated less mercury compared to the least harvested basin. Additionally, mercury concentrated less through the food web of this basin. The changes in the moderately impacted basin may be caused by sediments and other materials that transport mercury into the stream and increase water and food levels, but this high mercury was not being transferred to the other organisms in the food web. In conclusion, forest management had some effects on mercury at the base of food webs at a large scale, but patterns through space were inconsistent.

Abstract ¡@¡@The present study was undertaken to understand the accumulation of PCBs in the marine environment of Taiwan. Samples including oyster drills, oysters, sediments and seawater were collected from the West coast of Taiwan and analyzed by GC/ECD and GC/MS. ¡@¡@The concentration of PCBs in sediments was 31.05¡ã406.38 pg/g dry wt with the highest one at Tong-Kung. The PCBs in cultural oysters from Tong-Kung was 3.80 pg/g wet wt. Concentrations of PCBs in wild oysters from Tai-Si, Chi-Ku, and Pu-Dai were 123.57 pg/g wet wt, 2.93 pg/g wet wt, and 2.08 pg/g wet wt, respectively. The concentrations of PCBs in snails were in the range of 78.24 to 796.96 pg/g wet wt with the highest one from Tong-Kung. A positive correlations between the concentrations of PCBs in seawater and sediment (r=0.78; p<0.01) and in oysters and snails were also observed(r=0.79; p<0.01). The bioaccumulation of PCBs from seawater to oysters was about 72 times, and the biomagnification of PCBs from oysters to snails was 10 times.

Mercury concentrations in freshwater and marine biota are an ongoing concern, even in areas remote from local point sources, such as in the Canadian Arctic and sub-Arctic. Anadromous Arctic charr, which feed in the marine environment, have lower mercury concentrations than non-anadromous Arctic charr, which feed strictly in freshwater, but the two life-history forms have rarely been studied together, and the mechanisms driving the difference are unclear. Here, data from nine pairs of closely-located anadromous and non-anadromous Arctic charr populations were used to explore the impact of biological and life-history factors on individual total mercury concentration ([THg]) across a range of latitudes (49 – 81° N) in eastern Canada. From six of these sampling locations, additional samples of lower trophic level biota (i.e., algae, invertebrates, and forage fishes) were obtained in order to investigate patterns of total mercury (THg) and methylmercury (MeHg) biomagnification in the marine and lacustrine foodwebs supporting Arctic charr. Arctic charr mean [THg] ranged from 20 to 114 ng/g wet weight (ww) in anadromous populations, and was significantly higher in non-anadromous populations (all p < 0.01), ranging from 111 to 227 ng/g ww. Within-population variations in Arctic charr [THg] were best explained by fish age, and were also positively related to fork-length and δ15N-inferred trophic level. Across all sampling sites, the relationship between Arctic charr [THg] and fish age was significant and statistically similar in both life-history types, but only the non-anadromous fish demonstrated a significant relationship with trophic level. Fork-length and site latitude did not explain significant additional variation in Arctic charr [THg] across sampling locations. Trophic magnification factors were 1.98 – 5.19 for THg and 3.02 – 6.69 for MeHg in lacustrine foodwebs, and 1.59 – 2.82 for THg and 2.72 – 5.70 for MeHg in marine foodwebs, and did not differ significantly between the two feeding habitats for either THg or MeHg. The biomagnification rate of MeHg exceeded that of THg in both habitats. Mercury concentrations at the base of the foodweb were higher in the lacustrine environment (estimated at 17 – 139 ng/g dw for THg and 5 – 42 ng/g dw for MeHg) than in the marine environment (8 – 39 ng/g dw for THg and 1 – 11 ng/g dw for MeHg). The proportion of mercury in the methylated form was related to trophic level, and the relationship was statistically similar in the lacustrine and marine habitats. There was no effect of site latitude on mercury concentrations in marine or lacustrine biota, thus the difference between feeding habitats was consistent across a range of latitudes (56 – 72°N) in eastern Canada. We conclude that a difference in prey mercury concentration, driven by differential mercury concentrations at of the base of the lacustrine and marine foodwebs, is important for explaining the difference in mercury concentration between anadromous and non-anadromous in Arctic charr.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O mercúrio é um metal pesado que vem sendo reconhecido como um poluente potencialmente perigoso no ecossistema marinho devido à sua alta toxicidade e tendência a sofrer bioacumulação nos organismos e biomagnificação através das teias tróficas, podendo ser encontrado em elevadas concentrações em predadores de topo, como os atuns. O objetivo do presente estudo foi utilizar atuns e afins (Thunnus atlanticus, Thunnus albacares, Katsuwonus pelamis, Euthynnus alletteratus, Coryphaena hippurus e Sarda sarda) como indicadores da disponibilidade de mercúrio total (HgT) nas teias tróficas oceânicas do Rio de Janeiro. Os indivíduos foram coletados no período entre Fevereiro de 2009 a Janeiro de 2010, no desembarque pesqueiro da cidade de Cabo Frio, no Estado do Rio de Janeiro, no Sudeste do Brasil. A determinação das concentrações de mercúrio total foi baseada em Malm et al. (1989) e Bastos et al. (1998). As alíquotas de músculo e fígado foram digeridas através de uma mistura de ácidos e as concentrações de mercúrio total foram determinadas por espectrofotometria a vapor frio (FIMS-400, Perkin-Elmer). A precisão e exatidão dos métodos analíticos foram determinadas utilizando os materiais certificados, DORM-3 e DOLT-4, (NRC, Canadá). Os dados foram analisados estatisticamente através do programa STATISTICS 7.0 for Windows. As concentrações de mercúrio total (HgT) encontradas nos atuns e afins variaram significativamente entre as espécies para o músculo e fígado. As menores concentrações foram registradas em Coryphaena hippurus, (0,008 mg. Kg-1 no músculo e 0,003 mg. Kg-1 no fígado), enquanto as maiores concentrações foram reportadas no músculo de Thunnus atlanticus (1,300 mg. Kg-1) e no fígado de Sarda sarda (2,495 mg. Kg-1). Foram encontradas diferenças significativas entre as concentrações de mercúrio total musculares e hepáticas para Katsuwonus pelamis, Euthynnus alletteratus e Sarda sarda, com as concentrações mais elevadas encontradas no fígado. Além disso, o tamanho e o peso dos indivíduos foram fatores importantes, sendo positivamente correlacionados com as concentrações de mercúrio total em todas as espécies, com exceção das concentrações hepáticas encontradas em Katsuwonus pelamis e Euthynnus alleteratus. Ademais, nove indivíduos mostraram altas concentrações musculares, acima de 0,5 mg.Kg-1, limite máximo estabelecido pela Organização Mundial de Saúde (OMS) em peixes predadores para consumo humano. Estes resultados são preocupantes, uma vez que podem representar potencial risco à saúde. Considerando o mercúrio um micro poluente tóxico, as elevadas concentrações encontradas nesses peixes, podem causar efeitos neles e em seus consumidores. Portanto, é importante um contínuo monitoramento de peixes para auxiliar na sua conservação e permitir identificar quais espécies podem ser consumidas e com qual frequência. / Mercury has been recognized as a global pollutant potentially dangerous in the marine environment due its high toxicity and tendency to bioaccumulate in the organisms and undergoes biomagnification through food webs, being found in high concentrations in top predators, such astuna. The objective of the present study is use tuna and tuna-related fishes (Thunnus atlanticus, Thunnus albacares, Katsuwonus pelamis, Euthynnus alletteratus, Coryphaena hippurus and Sarda sarda) as indicators of the availability of total mercury (THg) in oceanic food webs of Rio de Janeiro.The individuals were collected between February of 2009 and January of 2010, in the fishing landing of the city of Cabo Frio, in Rio de Janeiro state, Southeastern Brazil. The total mercury (THg) determination was based on Malm et al. 1989 and Bastos et al. 1998. The aliquots of muscle and liver were digested with an acid mixture and THg concentrations were determined by Cold Vapor/AAS (FIMS-400, Perkin-Elmer). The accuracy and precision were determined by using DORM-3 and DOLT-4 (NRC, Canada).The results were analyzed statically throughout the program SATISTICS 7.0 for Windows. Total mercury concentrations (THg) found in tuna and tuna-related species varied significantly among themfor muscleand the liver. The lowest concentrations were found in Coryphaena hippurus, (0.008 mg. Kg-1 in the muscle and 0,003 mg. Kg-1 in the liver) while the highest concentrations were reported in the muscle of Thunnus atlanticus (1.300 mg. Kg-1) and in the liver of Sarda sarda (2.495 mg. Kg-1). In addition, it was found significantlydifferencesbetween total mercury hepatic and muscular concentrationsfor Katsuwonus pelamis, Euthynnus alletteratus and Sarda sarda with the highest total mercury concentrations registered in the liver.Furthermore, the size and weight were important factors, being positive significantly correlated with total mercury concentrations for all species, with exception of Katsuwonus pelamis and Euthynnus alleteratus in the liver. Nine individuals showed high muscular concentrations, above 0.5 mg.Kg-1, maximum established by the World Health Organization (WHO) in fishes for human consumption. These results are of concern, since may represent potential health risk. Considering mercury as a toxic micro pollutant, the high concentrations found in these fishes, may cause effects in themselves and their consumers.Thus, its important a continuous monitoring of fishes to help its conservation and allow to identify which species can be consumed and how often.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O mercúrio é um metal pesado que vem sendo reconhecido como um poluente potencialmente perigoso no ecossistema marinho devido à sua alta toxicidade e tendência a sofrer bioacumulação nos organismos e biomagnificação através das teias tróficas, podendo ser encontrado em elevadas concentrações em predadores de topo, como os atuns. O objetivo do presente estudo foi utilizar atuns e afins (Thunnus atlanticus, Thunnus albacares, Katsuwonus pelamis, Euthynnus alletteratus, Coryphaena hippurus e Sarda sarda) como indicadores da disponibilidade de mercúrio total (HgT) nas teias tróficas oceânicas do Rio de Janeiro. Os indivíduos foram coletados no período entre Fevereiro de 2009 a Janeiro de 2010, no desembarque pesqueiro da cidade de Cabo Frio, no Estado do Rio de Janeiro, no Sudeste do Brasil. A determinação das concentrações de mercúrio total foi baseada em Malm et al. (1989) e Bastos et al. (1998). As alíquotas de músculo e fígado foram digeridas através de uma mistura de ácidos e as concentrações de mercúrio total foram determinadas por espectrofotometria a vapor frio (FIMS-400, Perkin-Elmer). A precisão e exatidão dos métodos analíticos foram determinadas utilizando os materiais certificados, DORM-3 e DOLT-4, (NRC, Canadá). Os dados foram analisados estatisticamente através do programa STATISTICS 7.0 for Windows. As concentrações de mercúrio total (HgT) encontradas nos atuns e afins variaram significativamente entre as espécies para o músculo e fígado. As menores concentrações foram registradas em Coryphaena hippurus, (0,008 mg. Kg-1 no músculo e 0,003 mg. Kg-1 no fígado), enquanto as maiores concentrações foram reportadas no músculo de Thunnus atlanticus (1,300 mg. Kg-1) e no fígado de Sarda sarda (2,495 mg. Kg-1). Foram encontradas diferenças significativas entre as concentrações de mercúrio total musculares e hepáticas para Katsuwonus pelamis, Euthynnus alletteratus e Sarda sarda, com as concentrações mais elevadas encontradas no fígado. Além disso, o tamanho e o peso dos indivíduos foram fatores importantes, sendo positivamente correlacionados com as concentrações de mercúrio total em todas as espécies, com exceção das concentrações hepáticas encontradas em Katsuwonus pelamis e Euthynnus alleteratus. Ademais, nove indivíduos mostraram altas concentrações musculares, acima de 0,5 mg.Kg-1, limite máximo estabelecido pela Organização Mundial de Saúde (OMS) em peixes predadores para consumo humano. Estes resultados são preocupantes, uma vez que podem representar potencial risco à saúde. Considerando o mercúrio um micro poluente tóxico, as elevadas concentrações encontradas nesses peixes, podem causar efeitos neles e em seus consumidores. Portanto, é importante um contínuo monitoramento de peixes para auxiliar na sua conservação e permitir identificar quais espécies podem ser consumidas e com qual frequência. / Mercury has been recognized as a global pollutant potentially dangerous in the marine environment due its high toxicity and tendency to bioaccumulate in the organisms and undergoes biomagnification through food webs, being found in high concentrations in top predators, such astuna. The objective of the present study is use tuna and tuna-related fishes (Thunnus atlanticus, Thunnus albacares, Katsuwonus pelamis, Euthynnus alletteratus, Coryphaena hippurus and Sarda sarda) as indicators of the availability of total mercury (THg) in oceanic food webs of Rio de Janeiro.The individuals were collected between February of 2009 and January of 2010, in the fishing landing of the city of Cabo Frio, in Rio de Janeiro state, Southeastern Brazil. The total mercury (THg) determination was based on Malm et al. 1989 and Bastos et al. 1998. The aliquots of muscle and liver were digested with an acid mixture and THg concentrations were determined by Cold Vapor/AAS (FIMS-400, Perkin-Elmer). The accuracy and precision were determined by using DORM-3 and DOLT-4 (NRC, Canada).The results were analyzed statically throughout the program SATISTICS 7.0 for Windows. Total mercury concentrations (THg) found in tuna and tuna-related species varied significantly among themfor muscleand the liver. The lowest concentrations were found in Coryphaena hippurus, (0.008 mg. Kg-1 in the muscle and 0,003 mg. Kg-1 in the liver) while the highest concentrations were reported in the muscle of Thunnus atlanticus (1.300 mg. Kg-1) and in the liver of Sarda sarda (2.495 mg. Kg-1). In addition, it was found significantlydifferencesbetween total mercury hepatic and muscular concentrationsfor Katsuwonus pelamis, Euthynnus alletteratus and Sarda sarda with the highest total mercury concentrations registered in the liver.Furthermore, the size and weight were important factors, being positive significantly correlated with total mercury concentrations for all species, with exception of Katsuwonus pelamis and Euthynnus alleteratus in the liver. Nine individuals showed high muscular concentrations, above 0.5 mg.Kg-1, maximum established by the World Health Organization (WHO) in fishes for human consumption. These results are of concern, since may represent potential health risk. Considering mercury as a toxic micro pollutant, the high concentrations found in these fishes, may cause effects in themselves and their consumers.Thus, its important a continuous monitoring of fishes to help its conservation and allow to identify which species can be consumed and how often.

Polycyclic aromatic compounds (PACs) are a group of chemicals encompassing thousands of different aromatic, alkyl aromatic and heterocyclic hydrocarbons (i.e.- containing N, S, or O- atoms); 16 of which have been designated as priority pollutants due to their toxicity and prevalence. Several studies have highlighted increases in the concentrations of C1-C4 alkylated PACs and heterocyclic aromatic hydrocarbons such as dibenzothiophenes in the atmosphere, water, soil and sediments, plants, wildlife and fish in the Athabasca Oil Sands Region (AOSR). Although there has been considerable research attention related to the toxic, carcinogenic and mutagenic properties of PACs, there is an increasing awareness that these chemicals may also have profound endocrine disrupting properties in wildlife. North American river otter (Lontra canadensis) are good indicators of ecosystem health due to their ecology and sensitivity to environmental pollutants. In this thesis, we first demonstrated the utility of adopting paleotoxicological frameworks in defining environmental baseline levels of PACs and likely biological effects from exposure to these complex environmental mixtures. These methods allowed us to reconstruct historical PAC deposition patterns to impacted areas while simultaneously determining likely biological effects such as endocrine disruption. Next, we showed how PACs exhibited trophic dilution in a Boreal food chain dominated by river otters. Snails, prey and predator fish, as well as river otters were collected from four main study areas in the AOSR in northeastern Alberta, Canada. Bioaccumulation factors such as biota-sediment accumulation factors (BSAF) and trophic magnification factors (TMF) were used to evaluate the partitioning behavior of PACs in the environment and subsequent risks to biota. Our results revealed localized enrichment of certain PACs and subsequent metabolism in higher order vertebrates. Finally, we successfully combined ecotoxicological and physiological analyses paired with population genetic estimates to investigate endocrine disruption and population-level responses to exposure to PACs. River otters are known for their habitual use of latrine sites. Latrine sites represent a unique opportunity for biomonitoring programs to study river otters using indirect sampling methods. In this thesis, PACs were characterized and evaluated in sediment, lower and higher trophic biota with demonstrated impacts on endocrine processes and river otter population health. Effects-based assessments such as the ones presented in this thesis are more powerful for environmental monitoring programs than stressor-based assessment methods (such as describing presence/absence or levels of contaminants) as they provide greater biological context to monitoring data. In turn, these are helpful in selecting triggers for environmental effects monitoring or adaptive management programs.

No description available.

Ett flertal vattendrag i Sverige är idag förorenade (till viss grad), däribland Dalälven. Östersjön är ett utsatt hav vad gäller näringstillförsel, där Dalälven är en bidragande del till detta. I takt med att kunskapsnivån stiger kring hur vattenkvalitén påverkar organismer och människor så kan specifika åtgärder tas fram för enskilda vattendrag, för att förbättra kvalitén. Rapporten handlar om fiskodlingar och hur dem påverkas av utsläpp från mänskliga aktiviteter, samt hur odlingen påverkar dess omgivande vattendrag. Fiskodlingar används främst för att odla fisk som livsmedel, men även fisk som är avsedd för utplantering till sjöar och hav. Utplantering av fisk görs främst för att minska trycket på den vilda fisken. Att bedriva en fiskodling innebär stort ansvar för verksamhetsutövaren, där lagar och krav som är fastställda av riksdagen måste uppfyllas. För att kontrollera lagar och krav har man regelbundna kontroller vid fiskodlingar från olika myndigheter. Större delen av dagens fiskodlingar ligger i kontakt med sjöar och hav, och kan därmed påverkas av yttre faktorer i form av mänkliga aktiviteter, men även från själva odlingen i sig. Påverkan som bygger på utsläpp från dessa kan både vara positivt och negativt för vattendraget beroende på hur förutsättningarna hos denna ser ut. Fiskodlingar kan även placeras på land, men är dock betydligt mer kostsamt i jämförelse med en odling placerad i vattendrag. Det finns vissa risker med att bedriva en fiskodling i vattendrag, med avseende på sjukdomar och rymning. Sjukdomar inom en fiskodling kan resultera i slakt, och denna kan även spridas till utomstående vattendrag. En rymning kan bidra till hybridisering och därav påverka det vilda beståndet av fisk, den kan även rubba näringsväven hos vattendraget i form av konkurrens med det vilda beståndet, men även via bioackumulation och biomagnifikation. Det finns vissa faktorer som avgör placeringen av en fiskodling, detta allt efter hur förutsättningarna ser ut och vilken fisk som odlas. Slotts Lax AB, som är en fiskodlingsverksamhet i Dalarna, har valt att odla sin fisk i vattendrag, detta främst för att minimera kostnaderna och nyttja den miljö som erbjuds, vid Dalälven och Siljan. Fisk kan även odlas på land, detta görs främst för  att minimera riskerna med rymning av fisk och spridning av sjukdomar. / Several rivers in Sweden, including Dalälven, are today contaminated  to certain degree. As the knowledge rises around how water quality affects the organisms and humans can specific measures be developed for water bodies, to improve the quality. This thesis focuses on fish farms and how they are affected by emissions from human activity, and how fish farming affects its surrounding water. Fish farms are mainly used to raise fish for human consumption, but also fish intended for planting out in lakes and seas. The planting of fish is mainly to reduce the pressure on wild fish. Conducting a fish farm involves great responsibility for the operator, where laws and requirements that are established by the parliament must be met. For that purpose the laws and requirements are regularly checked at farms from different agencies. Most of the fish farms are currently in contact with lakes and seas, and those can be affected by external factors such as human activities, but also from the culturing itself. Impact of emissions from fish farms can be both positive and negative for the watercourse, depending on the conditions of the area. Fish farms can also be placed on land, but this would be far more costly in comparison with fish farming in waterways. There are certain risks associated with conducting a fish in streams such as, diseases and fish escaping. Diseases in the fish farming can result in the slaughter, and this can also spread to outside watercourses. An escape can contribute to hybridization which therefore affect the wild population of fish, it can also disrupt the food chain of the stream in the form of competition with the wild population, but also through bioaccumulation and biomagnification. There are certain factors that determine the location of a fish farm, depending on how the conditions look likes and what kind of fish species that are being grown. Slotts Lax AB, which is a fish farming business in Dalarna, have chosen to grow their fish in streams, primarily in order to minimize costs and use the environment offered by the Dalälven River and Lake Siljan. Fish can also be grown on land, this is done primarily to minimize the risks of escape and the spread of diseases.

Os estudos realizados em diversas partes do mundo sobre a utilização de pesticidas e os impactos que estes podem causar ao ambiente são uma das ações prioritárias para o desenvolvimento da agricultura, principalmente para aqueles pesticidas que são persistentes ao meio biótico e abiótico, como o inseticida heptacloro, que apesar de seu uso restrito para tratamento de madeira, ainda é muito usado no Brasil clandestinamente para outros fins. A maioria dos estudos realizados até agora sobre biomagnificação envolve o meio terrestre e uma pequena porcentagem desses é direcionada para o meio aquático e tem sido realizada em modelos de campo. O objetivo deste projeto foi determinar a CL50 96 horas para peixes a acumulação, biomagnificação e depuração do heptacloro em um modelo de sistema aquático. Como não existe nenhuma norma que defina o efeito cumulativo através dos níveis tróficos, pretendeu-se com esta pesquisa estimar a biomagnificação e depuração do heptacloro. Este estudo foi realizado em laboratório, em um modelo dividido em compartimentos individualizados, no qual somente as algas (Pseudokirchneriella subcapitata) foram submetidas por um período de 7 dias ao heptacloro, obtendo-se uma concentração final de 0,10 x 10-5µg heptacloro/µg algas, as quais posteriormente serviram de alimento para os microcrustáceos (Daphnia magna) durante 9 dias, que ao final concentraram 0,12 x 10-5 µg heptacloro/µg organismos. Por último, os peixes (Danio rerio) foram alimentados com microcrustáceos, no período de 5 dias, alcançando uma concentração final de 0,62 x 10-8 µg heptacloro/µg organismos. Nos últimos 9 dias, durante o período de depuração, os peixes foram alimentados em dias intercalados com microcrustáceos e ração sem contaminação com o produto, atingindo uma concentração final de 0,25 x 10-8 µg heptacloro/µg organismos. Nos testes realizados com esses três organismos, observou-se que a concentração ficou maior conforme o nível dentro do modelo proposto era mais alto, comprovando assim a hipótese do poder de bioacumulação, biomagnificação e depuração do heptacloro. / The studies carried out in different parts of the world about the pesticides use and the impacts that they can cause to the environment, are one of the priority actions for the agriculture development, mainly for those pesticides that are persistents in the biotic and abiotic environment, such as the heptachlor insecticide, which is still illegally used for others purposes in Brazil, although its use is limited for the wood treatment. The majority of the studies carried out until now about biomagnification involves the terrestrial environment and a small percentage of these studies are directed for the aquatic environment, and this small percentage has been carried out in field models. The aim of this project was to determine the LC50 96 hours for fish, accumulation, biomagnifications, and depuration of heptachlor in an aquatic system model and, as there isn?t any norm that defines the cumulative effect through trophic levels, it was claimed with this research to esteem the heptachlor biomagnification and depuration. This study was carried out in a laboratory, in a model divided in single chambers, in which the algae (Pseudokirchneriella subcapitata were submitted during 7 days to the heptaclhor, getting a final concentration of 0.10 x 10-5µg heptaclhor/µg algae, which was later served as food for the microcrustaceans (Daphnia magna) were submitted during 7 days to the heptaclhor, getting a final concentration of 0.10 x 10-5Mµg heptaclhor/µg algae, which was later served as food for the microcrustaceans (Daphnia magna) were fed with microcrustaceans, in the period of 5 days, reaching a final concentration of 0.62 x 10-8 µg heptaclhor/µg organisms. In the last 9 days, during the period of depuration, the fish were fed in days intercalated with microcrustaceans and ration without contamination with the product, reaching a final concentration of 0.25 x 10-8 µg heptacloro/µg organisms. In tests carried out with these three organisms, it was observed that the concentration was bigger as higher the level inside of the considered model, thus proving the hypothesis of the bioaccumulation, biomagnification, and depuration power of heptachlor.

O consumo de peixes e frutos do mar está associado à manutenção de uma dieta saudável em função da sua proteína de elevado valor biológico, da presença de ácidos graxos poli-insaturados e de importantes nutrientes como selênio, ferro, cálcio e fósforo. No entanto, esses organismos representam uma importante fonte de elementos-traço contaminantes para os seres humanos em função da bioacumulação desses elementos que também podem biomagnificar ao longo da cadeia alimentar. Apesar da ocorrência natural de elementos-traço no meio ambiente, sua concentração nos ecossistemas costeiros tem aumentado drasticamente em função de atividades antropogênicas, fazendo com que os organismos marinhos atuem como um elo da contaminação ambiental à contaminação humana. O presente trabalho avalia a concentração de elementos-traço em diferentes tecidos de organismos marinhos sob dois aspectos: (1) o risco alimentar associado ao consumo das espécies analisadas e (2) a bioacumulação dos elementos em diferentes tecidos. Para isso foram analisadas três espécies de peixes comercializadas na cidade de Santos (SP): Sphyraena guachancho (bicuda), Priacanthus arenatus (olho de cão) e Genidens genidens (bagre) e três espécies coletadas em diferentes pontos do Sistema Estuarino de Santos (SP): Callinectes danae (siri azul), Mytella guyanensis (mexilhão) e Mugil curema (parati). O hábito alimentar foi o principal critério para seleção das espécies. O risco alimentar, calculado pelo Índice Provisório de Risco (PHI) e pelo Índice Provisório de Risco Total (PTHI), apresentou valores elevados para Sphyraena guachancho (espécie piscívora) e para peixes e siris coletados no Sistema Estuarino de Santos. A bioacumulação foi associada à espécie, tecido e tipo de elemento avaliado. A espécie piscívora apresentou elevada concentração de Ba, Hg e Ag no tecido muscular, indicando a potencial biomagnificação desses elementos ao longo da cadeia alimentar. Genidens genidens, espécie detritívora, apresentou elevada concentração de Ba, Cd e Pb na nadadeira, possivelmente associado às estratégias de detoxificação da espécie, por meio da imobilização desses contaminantes no esporão ósseo. / The consumption of fish and seafood is associated with the maintenance of a healthy diet due to its protein of high biological value, the presence of polyunsaturated fatty acids and important nutrients as selenium, iron, calcium and phosphorus. However, these organisms represent an important source of contaminant trace elements for humans due to the bioaccumulation of these elements in tissues that can also biomagnify along the food chain. Despite the natural occurrence of trace elements in the environment, its concentration in coastal ecosystems has increased dramatically as a result of anthropogenic activities, causing marine organisms to act as a link between environmental and human contamination. The present work evaluates the concentration of trace elements in different tissues of marine organisms under two aspects: (1) the food risk associated with the consumption of the species analyzed and (2) the bioaccumulation of the elements in different tissues. Three species of fish commercialized in the city of Santos (SP) were analyzed: Sphyraena guachancho (bicuda), Priacanthus arenatus (dog eye) and Genidens genidens (catfish) and three species collected at different points of the Santos Estuarine System (SP): Callinectes danae (blue crab), Mytella guyanensis (mussel) and Mugil curema (parati). The eating habit was the main criteria for selection of the species. The food risk, calculated by means of the Provisional Hazard Index (PHI) and the Provisional Total Hazard Index (PTHI), presented high values for the piscivorous species Sphyraena guachancho and for fish and crabs collected in Santos Estuarine System. The bioaccumulation was associated with the species, tissue and type of element evaluated. The piscivorous species had a high concentration of Ba, Hg and Ag in muscle tissue, indicating the potential biomagnification of these elements along the food chain. Genidens genidens, a detivorous species, presented a high concentration of Ba, Cd and Pb in the fin, possibly associated with the detoxification strategies of the species, through the immobilization of these contaminants in the bone spur.