Assessment of Phthalate Esters and Physiological Biomarkers in Bottlenose Dolphins (Tursiops truncatus) and Killer Whales (Orcinus orca).

There is growing concern about the potential adverse health effects of phthalates (PAEs) on human health and the environment due to their extensive use as plasticizers and additives in commercial and consumer products. In this study, we assessed PAE concentrations in serum samples from aquarium-based delphinids (Tursiops truncatus, n = 36; Orcinus orca, n = 42) from California, Florida, and Texas, USA. To better understand the physiological effects of phthalates on delphinids, we also explored potential correlations between phthalates and the biomarkers aldosterone, cortisol, corticosterone, hydrogen peroxide, and malondialdehyde while accounting for sex, age, and reproductive stage. All PAEs were detected in at least one of the individuals. ΣPAE ranges were 5.995-2743 ng·mL-1 in bottlenose dolphins and 5.372-88,675 ng·mL-1 in killer whales. Both species displayed higher mean concentrations of DEP and DEHP. PAEs were detected in newborn delphinids, indicating transference via placenta and/or lactation. Linear mixed model results indicated significant correlations between aldosterone, month, location, status, and ΣPAEs in killer whales, suggesting that aldosterone concentrations are likely affected by the cumulative effects of these variables. This study expands on the knowledge of delphinid physiological responses to PAEs and may influence management and conservation decisions on contamination discharge regulations near these species.

Metal and metalloid maternal transfer in a newborn West Indian manatee (Trichechus manatus) two years after the northeastern oil spill disaster of 2019 in Brazil.

A large-scale oil spill along the northeastern Brazilian coast in 2019-2020 severely impacted primary manatee habitats in Brazil. This study aimed to assess metal and metalloid contamination in a dead manatee calf found following this oil spill. Several elements were detected, including chromium, iron, nickel, lead, and vanadium, which are crude oil components, and thallium, a component of dispersants used to degrade and dissipate crude oil. The presence of these contaminants in the manatee calf is indicative of maternal exposure, metabolism, and newborn transference via placenta and lactation. This is the first report of mother-calf metal transfer in manatees, highlighting the species' vulnerability and potential long-term population dynamics effects, and the first report for several metals and metalloids in these animals, laying the foundation for future research efforts. These findings highlight the urgent need for continued environmental monitoring, ecotoxicological assessments, and conservation initiatives.

Assessing variation in faecal glucocorticoid concentrations in gray whales exposed to anthropogenic stressors.

Understanding how individual animals respond to stressors behaviourally and physiologically is a critical step towards quantifying long-term population consequences and informing management efforts. Glucocorticoid (GC) metabolite accumulation in various matrices provides an integrated measure of adrenal activation in baleen whales and could thus be used to investigate physiological changes following exposure to stressors. In this study, we measured GC concentrations in faecal samples of Pacific Coast Feeding Group (PCFG) gray whales (Eschrichtius robustus) collected over seven consecutive years to assess the association between GC content and metrics of exposure to sound levels and vessel traffic at different temporal scales, while controlling for contextual variables such as sex, reproductive status, age, body condition, year, time of year and location. We develop a Bayesian Generalized Additive Modelling approach that accommodates the many complexities of these data, including non-linear variation in hormone concentrations, missing covariate values, repeated samples, sampling variability and some hormone concentrations below the limit of detection. Estimated relationships showed large variability, but emerging patterns indicate a strong context-dependency of physiological variation, depending on sex, body condition and proximity to a port. Our results highlight the need to control for baseline hormone variation related to context, which otherwise can obscure the functional relationship between faecal GCs and stressor exposure. Therefore, extensive data collection to determine sources of baseline variation in well-studied populations, such as PCFG gray whales, could shed light on cetacean stress physiology and be used to extend applicability to less-well-studied taxa. GC analyses may offer greatest utility when employed as part of a suite of markers that, in aggregate, provide a multivariate measure of physiological status, better informing estimates of individuals' health and ultimately the consequences of anthropogenic stressors on populations.

Trophic Chain Organochlorine Pesticide Contamination in a Highly Productive Upwelling Area in Southeastern Brazil.

Organochlorine pesticides (OCP) are legacy anthropogenic compounds known to persist for several years in the environment. The continuous use of some OCP, such as DDT, after restrictions in developing countries are cause of concern, due to their deleterious effects to marine life and humans. Studies assessing OCP contamination in coastal environments are still scarce in South America and there is a need to understand the impacts from trophic chain accumulation of these pollutants in marine life. In this study, we have assessed OCP levels in muscle and liver and estimated the biomagnification factor in several upwelling system trophic chain members, including fish, squid, and marine mammal from Southeastern Brazil. DDT degradation product DDE was the OCP detected in the highest concentrations in Franciscana dolphins (Pontoporia blainvillei), 86.4 ng·g-1 wet weight, and fish muscle and liver. In general, higher OCP levels were found in liver than in muscle, except for croaker. Biomagnification factors (BMF) of OCP in the top predator P. blainvillei and the carnivorous cutlass fish (Trichiurus lepturus) were on average between 0.2 and 1.8. Continued OCP monitoring in this region is warranted to better understand the distribution and fate of these compounds over time, with the goal to establish strategies for the conservation of local dolphin species and to assess human health risks from local coastal region populations.

Cortisol as a Stress Indicator in Fish: Sampling Methods, Analytical Techniques, and Organic Pollutant Exposure Assessments.

Cortisol is the main glucocorticoid released during stress responses in most fish and has been employed to investigate different stressors, including organic pollutants. This review discusses shifts in cortisol concentrations and examines different matrix sampling methods (invasive vs. minimally or non-invasive) and the main analytical cortisol determination techniques (immunoassays and liquid chromatography-tandem mass spectrometry). Assessments on organic pollutant exposure in fish and associated adverse effects are also discussed. Studies in this regard may aid in identifying organic pollutant toxicological modes of action, mechanistic response, toxicokinetics, and toxicodynamics, as well as pollution sources and associated health risks in fish, ultimately aiding in the development of effective management strategies to mitigate the impacts of organic pollutants on fish populations and their associated ecosystems.

Effects of vessel traffic and ocean noise on gray whale stress hormones.

Human use of marinescapes is rapidly increasing, especially in populated nearshore regions where recreational vessel traffic can be dense. Marine animals can have a physiological response to such elevated human activity that can impact individual health and population dynamics. To understand the physiological impacts of vessel traffic on baleen whales, we investigated the adrenal stress response of gray whales (Eschrichtius robustus) to variable vessel traffic levels through an assessment of fecal glucocorticoid metabolite (fGC) concentrations. This analysis was conducted at the individual level, at multiple temporal scales (1-7 days), and accounted for factors that may confound fGC: sex, age, nutritional status, and reproductive state. Data were collected in Oregon, USA, from June to October of 2016-2018. Results indicate significant correlations between fGC, month, and vessel counts from the day prior to fecal sample collection. Furthermore, we show a significant positive correlation between vessel traffic and underwater ambient noise levels, which indicates that noise produced by vessel traffic may be a causal factor for the increased fGC. This study increases knowledge of gray whale physiological response to vessel traffic and may inform management decisions regarding regulations of vessel traffic activities and thresholds near critical whale habitats.

Spatial distribution of per- and polyfluoroalkyl substances (PFAS) in waters from Central and South Florida.

Per- and polyfluoroalkyl substances (PFAS) are notoriously persistent pollutants that are found ubiquitously present in aquatic environments. They pose a big threat to aquatic life and human health given the bioaccumulation feature and significant adverse health effects associated. In our previous study, PFAS were found in surface waters from Biscayne Bay and tap waters from the East coast of South Florida, at levels that arouse human health and ecological concerns. Considering that Florida supports millions population as well as treasured, sensitive coastal and wetland ecosystems, we have expanded the PFAS monitoring study on the occurrence, composition, spatial distribution, and potential sources encompassing tap waters from counties on the West coast of South Florida and Central Florida, and surface waters from Tampa Bay, Everglades National Park adjacent canals, Key West, including Biscayne Bay area. A total of 30 PFAS were analyzed based on solid-phase extraction (SPE) followed by liquid chromatography tandem mass spectrometry (LC-MS/MS). PFAS were detected in all tap water (N = 10) and surface water samples (N = 38) with total concentrations up to 169 ng L-1. Higher PFAS concentrations (> 60 ng L-1) are mostly observed from polluted rivers or coastal estuaries in Biscayne Bay, and sites nearby potential points sources (military airbases, wastewater facilities, airports, etc.). Our findings on current PFAS contamination levels from diverse aquatic environments provide additional information for the development of more stringent screening levels that are protective of human health and the environmental resources of Florida, which is ultimately anticipated as scientific understanding of PFAS is rapidly growing.

American oysters as bioindicators of emerging organic contaminants in Florida, United States.

Per- and polyfluoroalkyl substances (PFAS) and phthalate esters (PAEs) are emerging contaminants of higher concern due to their wide industrial and commercial use, toxicity, and potential adverse health effects. In this study, we assessed PFAS and PAEs exposure in American oysters collected in three study sites in Florida, USA. Potential physiological effects of these contaminants were assessed by collecting oyster biometric data, calculating condition indices, and assessing oxidative stress levels in these individuals. Finally, a human health risk assessment was conducted based on the concentrations found in the consumable Tampa Bay (TB) oysters. All PFAS and PAEs compounds assessed in this study were detected in at least one oyster in all study sites. Among all locations, ΣPFAS concentration range was 0.611-134.78 ng·g-1 and ΣPAEs <0.328-1021 ng·g-1. Despite the smaller size of Biscayne Bay (BB) oysters, they displayed the highest concentrations of most of the PFAS and PAEs compounds, which is likely associated with population size, and other sources in the area. Condition index (CI) III was smaller in BB oysters, likely indicating a stressed population. Even though BB oysters were the most affected individuals, Marco Island (MI) oysters displayed the highest levels of lipid peroxidation, which can also be associated with environmental factors and decreased food availability. Conversely, TB oysters exhibited the highest levels of hydrogen peroxide, likely indicating a better defense mechanism in TB oysters compared to MI oysters. The human health risk assessment for TB oysters indicated low risk from PFAS and PAEs exposure, but there is no reference dose for other compounds and the human diet is wider than only oysters. Therefore, the risk of contaminant exposure is likely higher. This study demonstrates the value of integrating data on contaminant exposure and physiological responses of bioindicator specimens to better understand how emerging contaminants are affecting marine wildlife.

Subcellular metal partitioning as a novel tool in ecotoxicological elasmobranch assessments: The case of lesser numbfish (Narcine brasiliensis) affected by the Mariana dam disaster in Southeastern Brazil.

This study comprises a novel report on subcellular metal partitioning and metallothionein (MT) metal detoxification efforts in lesser numbfish (Narcine brasiliensis) electric ray specimens, as well as the first assessment on MT contents in any ray electric organ. Individuals sampled from an area in Southeastern Brazil affected by the Mariana dam rupture disaster were assessed concerning subcellular metal partitioning and MT metal-detoxification in the liver, gonads, electric organ and muscle of both adults and embryos. Yolk was also assessed when available. Relative total and heat-stable (bioavailable) metal and metalloid comparisons between adults and embryos in different developmental stages demonstrates maternal transfer of both total and bioavailable metals and significant MT associations demonstrate the detoxification of As, Ag, Mn, Ni, Cd, Co, Cu, Se and V through this biochemical pathway. Our findings expand the lacking ecotoxicological assessments for this near-threatened species and indicates significant ecological concerns, warranting further biomonitoring efforts.

Application of an Improved Chloroform-Free Lipid Extraction Method to Staghorn Coral (Acropora cervicornis) Lipidomics Assessments.

Lipids are excellent biomarkers for assessing coral stress, although staghorn coral data (Acropora cervicornis) is lacking. Lipid extraction is the most critical step in lipidomic assessments, usually performed using carcinogenic solvents. Efficient alternative using less toxic methods, such as the BUME method using butanol and methanol as extraction solvents, have not been applied to coral lipidomics evaluations. Thus, we aimed to develop a lipidomic approach to identify important coral health biomarkers by comparing different solvent mixtures in staghorn corals. Total lipid extraction was equivalent for both tested methods, but due to its efficiency in extracting polar lipids, the BUME method was chosen. It was then applied to different coral masses (0.33-1.00 g), resulting in non-significant differences concerning number of lipid classes and compounds. Therefore, this method can be successfully applied to coral assessments in a climate change context, with the added benefit of low sample masses, lessening coral sampling impacts.

Assessment of fecal steroid and thyroid hormone metabolites in eastern North Pacific gray whales.

Baleen whale fecal samples have high potential for endocrine monitoring, which can be used as a non-invasive tool to identify the physiological response to disturbance events and describe population health and vital rates. In this study, we used commercial enzyme-linked immunosorbent assays to validate and quantify fecal steroid (progestins, androgens and glucocorticoids) and thyroid hormone metabolite concentrations in eastern North Pacific gray whales (Eschrichtius robustus) along the Oregon coast, USA, from May to October of 2016-2018. Higher mean progestin metabolite concentrations were observed in postweaning females, followed by pregnant females. Mean androgen, glucocorticoid and thyroid metabolites were higher in mature males. Progestin, glucocorticoids and thyroid fecal metabolites varied significantly by year, with positive correlations between progestin and androgen, and between glucocorticoid and thyroid metabolites. We also present two case studies of a documented injured whale and a mature male displaying reproductive competitive behavior, which provide reference points for physiologically stressed individuals and adult breeding males, respectively. Our methods and findings advance the knowledge of baleen whale physiology, can help guide future research on whale physiology and can inform population management and conservation efforts regarding minimizing the impact of anthropogenic stressors on whales.

Occurrence and tissue distribution of organochlorinated compounds and polycyclic aromatic hydrocarbons in Magellanic penguins (Spheniscus magellanicus) from the southeastern coast of Brazil.

Seabirds are suitable biomonitors for several persistent organic pollutants (POP), such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs), although scarce studies of PAHs in seabirds are available, especially in South American populations. Therefore, this study aimed to assess OCPs, PCBs and PAHs, through gas chromatography-electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS) analyses, in liver (n = 9) and muscle tissue (n = 13) from juvenile Magellanic penguins (Spheniscus magellanicus) found stranded on the coast of Rio de Janeiro, Southeastern Brazil. DDT-related compounds were the most frequently detected OCP, and 4,4'-dichlorodiphenyldichloroethylene (DDE), the main DDT metabolite found in penguin tissues. OCP concentrations in liver were two-fold higher than in muscle tissues. Compound specific ratios identified recent exposure of penguins to some OCPs as well as evidence of legacy pollution associated with industrial sources. The predominant PCB congeners were PCB 8/5, PCB 138/160 and PCB 153/132, with concentrations ranging from

Total and subcellular Ti distribution and detoxification processes in Pontoporia blainvillei and Steno bredanensis dolphins from Southeastern Brazil.

Titanium (Ti), used in many dailyuse products, such as shampoos and sunscreen filters, in the form of TiO2 nanoparticles (NPs), may elicit adverse marine biota effects. Marine mammal Ti data is scarce, and subcellular distribution and detoxification information is non-existent. Ti concentrations and metalloprotein detoxification in Pontoporia blainvillei and Steno bredanensis dolphins from Southeastern Brazil were assessed. Metallothionein (MT) concentrations were determined spectrophotometrically, total and subcellular Ti, by ICP-MS and detoxification, by HPLC-ICP-MS. Ti detoxification occurred through MT complexation. Statistical Ti-MT associations were observed in S. bredanensis liver, indicating TiO2 NPs contamination, as Ti binds to MT only as NPs. MT-Ti correlations were observed for both the coastal (P. blainvillei) and offshore (S. bredanensis) dolphins, evidencing oceanic TiO2 diffusion. Ti detoxification through binding to reduced glutathione occurred in both species. Thermostable subcellular fractions are a valuable tool for cetacean Ti detoxification assessments and should be applied to conservation efforts.

Subcellular metal distributions and metallothionein associations in rough-toothed dolphins (Steno bredanensis) from Southeastern Brazil.

Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.

Interspecific variation of essential and non-essential trace elements in sympatric seabirds.

Chemical pollution is a growing issue for ocean ecosystems, threatening especially apex predators because they bioaccumulate persistent chemical pollutants such as non-essential trace elements. The trophic position is thus a key aspect when assessing the impacts of environmental pollution in marine organisms. Here we investigate the differences in the concentrations of essential (Cu, Cr, Se, and Zn) and non-essential elements (Hg, Al, As, Cd, and Sr), in muscular and hepatic tissues of four sympatric non-migratory seabirds (namely Sula leucogaster, Larus dominicanus, Fregata magnificens, and Thalasseus acuflavidus), which were found stranded along the Brazilian coast. The observed hepatic and muscular interspecific differences in elemental concentrations indicated that these sympatric seabirds are differently exposed to persistent contaminants circulating in the food web due to differences with respect to known feeding behaviours and prey preferences. Moreover, we found a consistent co-accumulative relationship between Se and Hg molar levels in liver tissues with mean Se:Hg molar ratio above 1. This relationship supports previous studies indicating that Se, via the formation of SeHg complexes, plays an essential biochemical role in the detoxification process of methyl mercury in seabirds. Our results suggest that feeding behaviour is an important factor associated to the interspecific differences of trace element concentrations in seabirds. However, traits other than feeding preferences (e.g. age) may also play an important role in the accumulation of these elements.

Variation in mercury concentration in juvenile Magellanic penguins during their migration path along the Southwest Atlantic Ocean.

The vulnerability of seabirds related to their migratory dynamics is frequently linked to environmental problems along the migration path. In this context, Magellanic penguins (Sphenicus magellanicus) seem to be vulnerable to an extensive range of environmental disturbances during their northward migration along the Atlantic waters of South America, which include by catch, marine debris ingestion, overfishing and environmental contamination. In this study, we investigate mercury accumulation in muscle and hepatic tissues of juveniles penguins collected along the Brazilian coast during three migratory seasonal years (2006, 2008 and 2012) and three areas along a latitudinal gradient. We found significant differences in Hg levels across the years, with higher hepatic Hg levels found in tissues of penguins sampled in 2008. The higher Hg levels in samples of penguins from 2008 might be attributed to variations in body condition or Hg uptake, associated with the trophic imbalance linked to an extreme El Niño event during that year. Significant differences in Hg accumulation across the latitudinal areas were also observed. The penguins sampled at the farthest area from the breeding ground presented the higher levels of Hg and also the poorest body condition. Body condition and other traits may influence the levels of chemical pollutants and decrease the migratory success rate in the juvenile age phase, compromising population dynamics.

Assessment of trace elements, POPs, (210)Po and stable isotopes ((15)N and (13)C) in a rare filter-feeding shark: The megamouth.

With less than 60 records being reported worldwide, the megamouth (Megachasma pelagios) is today one of the least known shark species inhabiting our oceans. Therefore, information concerning the biology and ecology of this enigmatic organism is very scarce and limited to feeding behaviour and preferred habitat. The present work reports new data on the concentrations of trace elements, organic mercury, POPs and (210)Po in hepatic and muscular tissues of a specimen found stranded in the southeastern coast of Brazil. Additionally, we provide new evidence based on stable isotope analysis (δ(15)N and δ(13)C) confirming the preference for the pelagic habitat and the zooplanktivorous feeding behaviour of the megamouth. These results are consistent with the low concentrations of organic pollutant compounds and other elements measured in our samples.

Guiana dolphins (Sotalia guianensis) as marine ecosystem sentinels: ecotoxicology and emerging diseases.

Guiana dolphins (Sotalia guianensis) are small cetaceans that inhabit coastal regions down to a 50 m depth. As a coastally distributed species, they are exposed to a variety of human-induced risks that include passive fishing nets, persistent environmental pollution, and emerging diseases. As a top predatorS. guianensis occupies an important ecological niche in marine ecosystems. However, this niche also exposes this dolphin to extensive biomagnification of marine contaminants that may accumulate and be stored throughout their life of about 30 years.In this paper, we have compiled available data on the Guiana dolphin as regards its exposure to chemical pollutants, pathogenic microbes, infectious diseases, and injuries caused by interactions with passive fishing gears. Our analysis of the data shows that Guiana dolphins are particularly sensitive to environmental changes.Although the major mortal threat to dolphins results from contact with fishing other human-related activities in coastal zones also pose risks and need more attention.Such human-related risks include the presence of persistent toxicants in the marine environment, such as PCBs and PBDEs. Residues of these chemicals have been detected in Guiana dolphin's tissues at similar or higher levels that exist in cetaceans from other known polluted areas. Another risk encountered by this species is the non lethal injuries caused by fishing gear. Several incidents of this sort have occurred along the Brazilian coast with this species. When injuries are produced by interaction with fishing gear, the dorsal fin is the part of the dolphin anatomy that is more affected, commonly causing severe laceration or even total loss.The Guiana dolphins also face risks from infectious diseases. The major ones thus far identified include giardiasis, lobomycosis, toxoplasmosis, skin and skeletal lesions. Many bacterial pathogens from the family Aeromonadaceae and Vibrionaceae have been isolated from Guiana dolphins. Several helminth species have also been observed to affectS. guianensis. These results suggest a vulnerability of this species to environmental disturbances. Moreover, there is some evidence that the effects of some infectious diseases may be enhanced from stress caused by habitat impairment. For example, certain diseases and pathogenic organisms in S.guianensis may be associated with the high levels of endocrine-disruptor contaminants(e.g., PCBs; DDTs; PBDEs) that have been detected in marine waters.Although the data available on S. guianensis is growing, most of the work has been focused on a small portion of the species total area of distribution. Most studies,to date, have been carried out in the Southern region of the distribution, and in north eastern Brazil. Few studies have been conducted in the northern region of the South America or in Central America. Therefore, future studies should be conducted that address the heterogeneity of this species total distribution.The biology and ecology of the Guiana dolphin renders this species potentially useful as a sentinel species for detecting environmental changes, such as chemical and biological pollution. Research about this dolphin is encouraged as a way to assess what coastal environmental changes have occurred and to continue evaluating the health status of this vulnerable species in a changing environment.

Small cetaceans found stranded or accidentally captured in southeastern Brazil: bioindicators of essential and non-essential trace elements in the environment.

Essential (Cu, Mn, Se and Zn) and non-essential (Cd and Hg) elements were analyzed in the hepatic tissue of 22 individuals of seven different species of small cetaceans (Feresa attenuata; Orcinus orca; Pontoporia blainvillei; Sotalia guianensis; Stenella frontalis; Steno bredanensis; Tursiops truncatus) accidentally caught in fishing nets or found stranded along the northern coast of the state of Rio de Janeiro, Brazil, between 2001 and 2010. Atlantic spotted dolphin (S. frontalis) showed the highest levels of Cd (20.23µgg(-1), dry weight), while rough-toothed dolphin (S. bredanensis) showed the highest levels of Hg (825.9µgg(-1)dw) and Se (221.9µgg(-1)dw). Killer whale (O. orca) presented the highest levels of Cu (64.80µgg(-1)dw) and Zn (2220µgg(-1)dw), and Guiana dolphin (S. guianensis), the highest level of Mn (13.05µgg(-1)dw). Cu, Hg, Mn and Zn in the hepatic tissue of killer whale (O. orca), Cu, Hg, Mn, Se and Zn in the hepatic tissue of rough-toothed dolphin (S. bredanensis) and Cd and Zn in the hepatic tissue of Guiana dolphin (S. guianensis) were significantly higher when compared to other studies with these species around the world. No significant correlations were observed between element accumulation and sex, sexual maturity and body length. An analysis of the interelemental relationships in the Guiana dolphin specimens showed strong positive correlations between Cd and Se, Cu and Zn, and Hg and Se. Differences were observed in the bioaccumulation of elements between the analyzed species, probably related to each species feeding habit, and differences between different element concentrations in the different dolphin species were probably due to the preference for certain preys and their bioavailability in the environment. Thus, the bioavailability of the analyzed elements in the marine environment should also be taken in consideration. This study also presents the first data ever reported for pygmy killer whale (F. attenuata) regarding trace element concentrations in hepatic tissue.

Efeito agudo do exercício físico aeróbico sobre a pressäo arterial de hipertensos controlados submetidos a diferentes volumes de treinamento / Acute effect of aerobic physical exercise in blood pressure of controlled hypertensives submitted to different volumes of training

O presente estudo teve como objetivo analisar o efeito agudo de duas sessöes de exercício físico aeróbico de diferentes volumes, na magnitude da eventual queda pressórica observada no período pós-exercício em indivíduos hipertensos controlados, de ambos os sexos, com idade entre 35 e 65 anos, praticantes de exercícios físicos regulares. Buscou-se verificar se há hipotensäo aguda causada pele exercício físico em indivíduos hipertensos controlados e se a duraçäo da sessäo de exercício físico poderia influenciar na magnitude dessa hipotensäo. Os sujeitos (n=23) foram submetidos a uma sessäo controle e duas sessöes complementares de exercício físico dinâmico em cicloergômetro com 25 a 45 minutos de duraçäo, a 75 porcento da freqüência cardíaca máxima. Os valores da pressäo arterial sistólica (PAS), pressäo arterial diastólica (PAD) e freqüência cardíaca (FC) foram medidos no pré-exercício (após 15 minutos de repouso) e no período pós-exercício (primeiro, quinto, décimo, vigésimo e trigésimo minuto de recuperaçäo) tanto nas duas sessöes experimentais, como na sessäo controle. Os resultados obtidos convergem para uma diminuLçäo nos níveis de pressäo arterial no período de recuperaçäo nas sessöes experimentais, quando comparados às sessöes controle sem exercícios físicos. Além disso, observou-se também que a magnitude pressórica provocada pelo exercício é influenciada pela sua duraçäo, isto é, o exercício físico com duraçäo de 45 minutos proporcionou queda mais ecentuada da PAS e PAD que na sessäo de 25 minutos, quando comparados à sessäo controle. Em relaçäo à comparaçäo entre as duas sessöes experimentais, observou-se queda significativa da PAS no primeiro minuto de recuperaçäo, enquanto que a PAD näo apresentou diferença significativa em nenhum momento da recuperaçäo. A magnitude e duraçäo do efeito hipotensor do exerc1cio físico parecem ser maiores após uma sessäo de maior volume quando comparados a uma sessäo de menor volume, verificando-se a duraçäo do exercício na hipotensäo pós-exercício.(au)